fuchsia.sys2

An interface for resolving a URL to a component.

This interface is implemented by components that provide support for loading components with a particular URL scheme. For example, the Fuchsia package component resolver exposes a service with this interface to resolve component URLs using the "fuchsia-pkg://" scheme.

To use a resolver to resolve URLs within your realm, register it in your realm's manifest. (TODO: explain in more detail)

Note: The component manager is the only intended direct client of this interface.

Resolve

Resolves a component with the given URL.

component_url is the unescaped URL of the component to resolve.

If successful, returns information about the component that was resolved.

On failure, returns a ResolverError error.

Request

Name	Type
`component_url`	`string`

Response

Name	Type
`result`	`ComponentResolver_Resolve_Result`

CrashIntrospect

When a thread from a component using the ELF runner crashes, the thread koid along with other information is stored. This protocol can be used to retrieve that stored information.

FindComponentByThreadKoid

Given a thread koid, returns the information that was stored when the ELF runner observed a crash from that thread.

The information for a crash is deleted when it is accessed or when 10 minutes have passed, whichever comes first.

If there is no information available on the given thread koid, zx::Status::NOT_FOUND is returned.

Request

Name	Type
`thread_koid`	`zx/koid`

Response

Name	Type
`result`	`CrashIntrospect_FindComponentByThreadKoid_Result`

EventSource

Defined in fuchsia.sys2/events.fidl

Subscribe to events in component manager.

Subscribes to the events of the provided EventTypes.

Returns a EventStreamSync which can be used to expect the registered types.

Errors:

RESOURCE_UNAVAILABLE when the component hasn't been granted the capability to subscribe to some event in the requested events.

Request

Name	Type
`events`	`vector<EventSubscription>[2]`
`stream`	`EventStream`

Response

Name	Type
`result`	`EventSource_Subscribe_Result`

TakeStaticEventStream

Returns the server end of a static EventStream of the provided path if it exists. If this stream is discarded afterward then all sync events on the channel will be immediately canceled. Errors:

RESOURCE_UNAVAILABLE when an event stream at the requested path is unavailable or has already been taken.

Request

Name	Type
`path`	`string[4096]`

Response

Name	Type
`result`	`EventSource_TakeStaticEventStream_Result`

EventStream

Defined in fuchsia.sys2/events.fidl

Listener for events on the component hierarchy. The server won't wait for the client to handle the request before sending more events.

OnEvent

Request

Name	Type
`event`	`Event`

Handler

Defined in fuchsia.sys2/events.fidl

Every Event supports this basic handler to allow resumption.

Resume

Resumes/unblocks from an event.

Request

<EMPTY>

Response

<EMPTY>

LifecycleController

Defined in fuchsia.sys2/lifecycle_controller.fidl

A protocol exposed in a component's hub to allow component tools to resolve, bind, stop component manifests.

Bind

Binds to the component designated by the provided relative moniker relative to the component to which the protocol is scoped.

The function returns once the component is successfully bound, or the operation fails.

Request

Name	Type
`moniker`	`string[4096]`

Response

Name	Type
`result`	`LifecycleController_Bind_Result`

CreateChild

Creates a child component instance dynamically. This method is equivalent to fuchsia.sys2/Realm.CreateChild. See its documentation for more details.

parent_moniker is the moniker of the component that owns the collection in which the child will be created, relative to the component to which the protocol is scoped.

Request

Name	Type
`parent_moniker`	`string[4096]`
`collection`	`CollectionRef`
`decl`	`ChildDecl`
`args`	`CreateChildArgs`

Response

Name	Type
`result`	`LifecycleController_CreateChild_Result`

DestroyChild

Destroys a dynamically-created component instance. This method is equivalent to fuchsia.sys2/Realm.DestroyChild. See its documentation for more details.

parent_moniker is the moniker of the component that owns the collection in which the child will be destroyed, relative to the component to which the protocol is scoped.

Request

Name	Type
`parent_moniker`	`string[4096]`
`child`	`ChildRef`

Response

Name	Type
`result`	`LifecycleController_DestroyChild_Result`

Resolve

Resolves the component designated by the provided relative moniker relative to the component to which the protocol is scoped.

The function returns once the component successfully resolves, or the operation fails.

Request

Name	Type
`moniker`	`string[4096]`

Response

Name	Type
`result`	`LifecycleController_Resolve_Result`

Stop

Stops the component designated by the provided relative moniker relative to the component to which the protocol is scoped.

The function returns once the component successfully stops, or the operation fails.

Request

Name	Type
`moniker`	`string[4096]`
`is_recursive`	`bool`

Response

Name	Type
`result`	`LifecycleController_Stop_Result`

Realm

Defined in fuchsia.sys2/realm.fidl

A protocol used by a component instance to manage its own realm, such as for binding to its children.

Requests to this protocol are processed in the order they are received. Clients that wish to send requests in parallel should open multiple connections.

The component framework provides this service to components that use fuchsia.sys2.Realm.

DEPRECATED - Use the SDK version of this protocol, fuchsia.component.Realm

CreateChild

Creates a child component instance dynamically. When this function returns successfully, the instance exists, but it may not be running.

The environment of the child instance is determined by the environment of the collection. decl must not set environment.

Errors:

INVALID_ARGUMENTS: collection is not a valid reference or child is not a valid declaration.
COLLECTION_NOT_FOUND: collection does not exist.
INSTANCE_ALREADY_EXISTS: decl.name already exists in collection.
INSTANCE_CANNOT_RESOLVE: child's component declaration failed to resolve in a SingleRun collection.
NO_SPACE: Could not allocate storage for the new instance.
INSTANCE_DIED: This realm no longer exists.

Request

Name	Type
`collection`	`CollectionRef`
`decl`	`ChildDecl`
`args`	`CreateChildArgs`

Response

Name	Type
`result`	`Realm_CreateChild_Result`

DestroyChild

Destroys a dynamically-created component instance. When this function returns, the instance is destroyed and has stopped running. However, cleanup of the component's resources (such as its isolated storage) may happen in the background after this function returns.

Errors:

INVALID_ARGUMENTS: child is not a valid reference or does not refer to a dynamic instance.
INSTANCE_NOT_FOUND: child does not exist.
COLLECTION_NOT_FOUND: collection does not exist.
INSTANCE_DIED: This realm no longer exists.

Request

Name	Type
`child`	`ChildRef`

Response

Name	Type
`result`	`Realm_DestroyChild_Result`

ListChildren

Returns an iterator that lists all instances in a collection.

NOTE: The results are not guaranteed to be consistent. Instances may be created or destroyed while the iterator is live, but those changes won't be observed by the iterator after this method returns.

Errors:

INVALID_ARGUMENTS: collection is not a valid reference or iter does not have ZX_RIGHT_WAIT.
COLLECTION_NOT_FOUND: collection does not exist.
INSTANCE_DIED: This realm no longer exists.
If iter does not have standard channel rights, this function may return ACCESS_DENIED or component manager may close iter.

Request

Name	Type
`collection`	`CollectionRef`
`iter`	`request<ChildIterator>`

Response

Name	Type
`result`	`Realm_ListChildren_Result`

OpenExposedDir

Opens the exposed directory of a child component instance. When this function successfully returns, exposed_dir is bound to a directory that contains the capabilities which the child exposed to its realm via ComponentDecl.exposes (specified via "expose" declarations in the component's manifest). The child component will not start as a result of this call. Instead, starting will occur iff the parent binds to one of the capabilities contained within exposed_dir.

exposed_dir is open as long as child exists.

Errors:

INVALID_ARGUMENTS: child is not a valid child reference.
INSTANCE_NOT_FOUND: child does not exist.
INSTANCE_CANNOT_RESOLVE: child's component declaration failed to resolve.
INSTANCE_DIED: This realm no longer exists.

Request

Name	Type
`child`	`ChildRef`
`exposed_dir`	`request<fuchsia.io/Directory>`

Response

Name	Type
`result`	`Realm_OpenExposedDir_Result`

StorageAdmin

DeleteComponentStorage

Deletes the contents of the storage for this component. Does not delete the component's subdirectory itself from the backing directory.

Request

Name	Type
`relative_moniker`	`string[4096]`

Response

Name	Type
`result`	`StorageAdmin_DeleteComponentStorage_Result`

ListStorageInRealm

Lists the descendant components under the specified realm that use the storage capability. Returns INSTANCE_NOT_FOUND if the realm does not exist, and INVALID_ARGS if |relative_moniker| is malformed.

Request

Name	Type
`relative_moniker`	`string[4096]`
`iterator`	`request<StorageIterator>`

Response

Name	Type
`result`	`StorageAdmin_ListStorageInRealm_Result`

OpenComponentStorage

Opens the isolated directory for the given component. The open request will provision the storage if it hasn't been already.

Request

Name	Type
`relative_moniker`	`string[4096]`
`flags`	`uint32`
`mode`	`uint32`
`object`	`request<fuchsia.io/Node>`

OpenComponentStorageById

Opens the isolated directory for the given storage ID. The open request will provision the storage if it hasn't been already.

Request

Name	Type
`id`	`string[32]`
`object`	`request<fuchsia.io/Node>`

Response

Name	Type
`result`	`StorageAdmin_OpenComponentStorageById_Result`

StorageIterator

An iterator protocol for returning a set of components using a storage capability. See |StorageAdmin.ListStorageInRealm| for more information.

Retrieve the next set of components using the storage capability. The returned monikers are relative to the component that declares the storage capability. Returns an empty vector after all components have been returned.

Request

<EMPTY>

Response

Name	Type
`relative_monikers`	`vector<string>`

SystemController

Defined in fuchsia.sys2/system_controller.fidl

An interface implemented by ComponentManager that requests the ComponentManager stop all components and exit.

Shutdown

Stop all components, return an empty result, close this protocol's channel, and exit ComponentManager. If this is the root ComponentManager is exited we expect the system will reboot.

Request

<EMPTY>

Response

<EMPTY>

WorkScheduler

Framework service: API for scheduling and canceling work. Each component instance can access work items that it has scheduled (but not others' scheduled work items). Work items are scheduled roughly at the specified time and frequency; the service implementation may specify its notion of roughly, and may provide a configuration API to tune this notion.

Each scheduled work item is identified by a client-provided WorkId. Each scheduled work item has a WorkId that is unique with respect to scheduled work items belonging to the same component instance.

CancelWork

Cancel the scheduled work item specified by work_id.

Request

Name	Type
`work_id`	`WorkId`

Response

Name	Type
`result`	`WorkScheduler_CancelWork_Result`

ScheduleWork

Schedule a new work item identified by work_id. The work item is to be scheduled roughly at the time corresponding to work_request.start. When work_request.period is specified, reschedule work roughly every work_request.period until the the work item is canceled.

Request

Name	Type
`work_id`	`WorkId`
`work_request`	`WorkRequest`

Response

Name	Type
`result`	`WorkScheduler_ScheduleWork_Result`

WorkSchedulerControl

Framework service: Administrative API for controlling parameters of the WorkScheduler framework service. So long as there are work items with deadlines in the next batch_period, the WorkScheduler will sleep for batch_period, then wake up and immediately dispatch a batch of work items: all those with past deadlines. It will repeat this process until no work items would be scheduled in the next batch_period, at which point it will go to sleep until the next deadline. This strategy ensures that each work item is dispatched approximately within batch_period of its deadline.

GetBatchPeriod

Get the current period between WorkScheduler attempts to dispatch a batch of work. batch_period is a non-negative 64-bit integer in the range [0, 2^63-1], representing a number of nanoseconds between dispatching batches of work.

Request

<EMPTY>

Response

Name	Type
`result`	`WorkSchedulerControl_GetBatchPeriod_Result`

SetBatchPeriod

Set the current period between WorkScheduler attempts to batch and dispatch a batch of work. batch_period is a non-negative 64-bit integer in the range [0, 2^63-1], representing a number of nanoseconds between dispatching batches of work.

Request

Name	Type
`batch_period`	`zx/duration`

Response

Name	Type
`result`	`WorkSchedulerControl_SetBatchPeriod_Result`

Worker

Component-exposed service: Work scheduler connects to this service to invoke scheduled work item callbacks. The service implementation is responsible for invoking the code that corresponds to the scheduled work item identified by work_id.

Note: The intent of exposing this service is to expose it to the WorkScheduler service provider (i.e., the framework) and no one else.

DoWork

Request

Name	Type
`work_id`	`WorkId`

Response

Name	Type
`result`	`Worker_DoWork_Result`

STRUCTS

CapabilityRef

A reference to a capability declared in this component.

Field	Type	Description	Default
`name`	`string[100]`		No default

ChildRef

A reference to one of the component's child instances.

Field	Type	Description	Default
`name`	`fuchsia.component/name`	The name assigned to the child by its parent. If `collection` is set, `name` is scoped to `collection` and the child is a dynamic instance. Required.	No default
`collection`	`fuchsia.component/name`	The collection `name` belongs to. If omitted, `name` references a static instance. This field must be omitted if the `ChildRef` is being used in a component declaration. Optional.	No default

CollectionRef

A reference to one of the component's collections.

Field	Type	Description	Default
`name`	`fuchsia.component/name`		No default

ComponentResolver_Resolve_Response resource

Field	Type	Description	Default
`component`	`Component`		No default

CrashIntrospect_FindComponentByThreadKoid_Response

Field	Type	Description	Default
`info`	`ComponentCrashInfo`		No default

DebugRef

A reference to the environment's debug capabilities.

<EMPTY>

EventSource_Subscribe_Response

Defined in fuchsia.sys2/events.fidl

<EMPTY>

EventSource_TakeStaticEventStream_Response resource

Defined in fuchsia.sys2/events.fidl

Field	Type	Description	Default
`server_end`	`request<EventStream>`		No default

FrameworkRef

A reference to the component framework itself.

<EMPTY>

LifecycleController_Bind_Response

Defined in fuchsia.sys2/lifecycle_controller.fidl

<EMPTY>

LifecycleController_CreateChild_Response

Defined in fuchsia.sys2/lifecycle_controller.fidl

<EMPTY>

LifecycleController_DestroyChild_Response

Defined in fuchsia.sys2/lifecycle_controller.fidl

<EMPTY>

LifecycleController_Resolve_Response

Defined in fuchsia.sys2/lifecycle_controller.fidl

<EMPTY>

LifecycleController_Stop_Response

Defined in fuchsia.sys2/lifecycle_controller.fidl

<EMPTY>

ParentRef

A reference to a component's parent instance.

<EMPTY>

Realm_CreateChild_Response

Defined in fuchsia.sys2/realm.fidl

<EMPTY>

Realm_DestroyChild_Response

Defined in fuchsia.sys2/realm.fidl

<EMPTY>

Realm_ListChildren_Response

Defined in fuchsia.sys2/realm.fidl

<EMPTY>

Realm_OpenExposedDir_Response

Defined in fuchsia.sys2/realm.fidl

<EMPTY>

SelfRef

A reference to the component itself.

<EMPTY>

StorageAdmin_DeleteComponentStorage_Response

<EMPTY>

StorageAdmin_ListStorageInRealm_Response

<EMPTY>

StorageAdmin_OpenComponentStorageById_Response

<EMPTY>

WorkSchedulerControl_GetBatchPeriod_Response

Field	Type	Description	Default
`batch_period`	`zx/duration`		No default

WorkSchedulerControl_SetBatchPeriod_Response

<EMPTY>

WorkScheduler_CancelWork_Response

<EMPTY>

WorkScheduler_ScheduleWork_Response

<EMPTY>

Worker_DoWork_Response

<EMPTY>

ENUMS

AllowedOffers strict

Type: uint32

Defined in fuchsia.sys2/collection_decl.fidl

The kinds of offers that can target the children in a collection.

Name Value Description

STATIC_ONLY

1

Only static offers may target components in the collection. "Static offers" are the offers in the ComponentDecl that target the collection itself.

This is the default behavior.

STATIC_AND_DYNAMIC

2

Both static offers and dynamic offers may target components in the collection. "Static offers" are the offers in the ComponentDecl that target the collection itself. "Dynamic offers" are additional offers that are passed to CreateChild at runtime.

DependencyType strict

Type: uint32

Defined in fuchsia.sys2/offer_decl.fidl

Describes the type of dependency implied by the capability.

Name	Value	Description
`STRONG`	`1`	A strong dependency which may be required by components that use it.
`WEAK`	`2`	A weak dependency which is allowed to form a cycle. Components that use a weak dependency must support the dependency being unavailable at arbitrary times.
`WEAK_FOR_MIGRATION`	`3`	A weak dependency specifically used to mark cyclic dependencies from migrated v1 components.

Durability strict

Type: uint32

Defined in fuchsia.sys2/collection_decl.fidl

The durability of component instances created in a collection.

Name	Value	Description
`PERSISTENT`	`1`	An instance exists until either it or its parent is destroyed.
`TRANSIENT`	`2`	An instance exists until either its parent instance is stopped or it is explicitly destroyed.
`SINGLE_RUN`	`3`	An instance is started upon creation and is immediately destroyed when it stops.

EnvironmentExtends strict

Type: uint32

Specifies how a declared environment's initial set of properties are assigned.

Name	Value	Description
`NONE`	`0`	The environment has no initial set of properties.
`REALM`	`1`	The environment's initial set of properties are inherited from its realm. Inherited properties include any fields defined in `EnvironmentDecl`.

EventMode strict

Type: uint32

Defined in fuchsia.sys2/events.fidl

Describes the consumption mode of an event.

Name	Value	Description
`ASYNC`	`0`	The event source dispatches the event and doesn't wait for the listener to handle it.
`SYNC`	`1`	The event source awaits the listener to notify it that it's done handling the event.

EventType strict

Type: uint32

Defined in fuchsia.sys2/events.fidl

These EventTypes are used for the EventStream protocol. They are FIDL versions of the EventType enum in hooks.rs and have the same meaning.

Name	Value	Description
`CAPABILITY_REQUESTED`	`1`	A capability provided by this component has been requested. The event payload carries the request channel.
`CAPABILITY_ROUTED`	`2`	A capability is being requested by a component and its routing has also been determined. The event propagation system is used to supply the capability being requested.
`PURGED`	`3`	An instance was purged successfully. The instance is stopped and no longer exists in the parent's realm.
`DIRECTORY_READY`	`4`	A directory exposed to the framework by a component is available.
`DISCOVERED`	`5`	A component instance was discovered. This is the first stage in the lifecycle of components. Dispatched for dynamic children when they're created, for static children when their parent is resolved, and for the root when the component manager starts.
`DESTROYED`	`6`	Destruction of an instance has begun. The instance is guranteed to be shut down at this point. The instance still exists in the parent's realm but will soon be removed. The instance is considered destroyed when this event is received. TODO(fxbug.dev/39417): Ensure the instance is stopped before this event.
`RESOLVED`	`7`	An instance's declaration was resolved successfully for the first time.
`STARTED`	`8`	This instance has started, according to component manager. However, if this is an executable component, the runner has further work to do to launch the component.
`STOPPED`	`9`	An instance was stopped successfully. This event must occur before Purged.
`RUNNING`	`10`	If requested, this event is dispatched on subscription and indicates that the instance has already started and is still running.

OnTerminate strict

Type: uint32

Defined in fuchsia.sys2/child_decl.fidl

Describes the action to take if this component instance terminates unexpectedly.

Name	Value	Description
`NONE`	`0`	No action, the default
`REBOOT`	`1`	Trigger a graceful system reboot if the component terminates for any reason. This is a specialized feature gated by Component Framework security policy.

ResolverError strict

Type: uint32

The possible error conditions returned by ComponentResolver.

Name	Value	Description
`INTERNAL`	`1`	An unexpected error occurred.
`IO`	`2`	A general IO error occurred.
`INVALID_ARGS`	`3`	The component URL was malformed.
`NOT_SUPPORTED`	`4`	The repository specified in the URL is unsupported.
`MANIFEST_NOT_FOUND`	`5`	The component manifest was not found.
`PACKAGE_NOT_FOUND`	`6`	The component's package was not found.
`NO_SPACE`	`7`	Insufficient space on device to store component's package.
`RESOURCE_UNAVAILABLE`	`8`	The component is temporarily unavailable.

StartupMode strict

Type: uint32

Defined in fuchsia.sys2/child_decl.fidl

Describes under what conditions the component may be started.

Name	Value	Description
`LAZY`	`0`	Start component instance only when another instance binds to it.
`EAGER`	`1`	Start component instance as soon as parent starts. This mode is only supported for statically declared children -- a dynamic instance may only be started by binding to it.

StorageId strict

Type: uint32

Declares which identifier to use to key a component's isolated storage directory.

Name	Value	Description
`STATIC_INSTANCE_ID`	`1`	Isolated storage directories are keyed using a component's instance ID specified in the component ID index. Components which are not listed in the index cannot use or open this storage capability.
`STATIC_INSTANCE_ID_OR_MONIKER`	`2`	Isolated storage directories are keyed using a component's instance ID if one is specified in the component ID index. Otherwise, a component's relative moniker from the storage capability is used to key its isolated storage directory.

TABLES

CapabilityRequestedError

Defined in fuchsia.sys2/events.fidl

Error payload for CapabilityRequested events

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	The name of the capability being requested.

CapabilityRequestedPayload resource

Defined in fuchsia.sys2/events.fidl

Payload for CapabilityRequested events

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	The name of the capability.
2	`capability`	`handle<channel>`	A handle to the server end of the channel to host capability.

CapabilityRoutedError

Defined in fuchsia.sys2/events.fidl

Error payload for CapabilityRouted events

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	Name of the capability being requested.

CapabilityRoutedPayload resource

Defined in fuchsia.sys2/events.fidl

Payload for CapabilityRouted events

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	Name of capability being requested.

ChildDecl

Defined in fuchsia.sys2/child_decl.fidl

Statically declares a child component instance.

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	The name assigned to the child by its parent. Must be non-empty, unique among all siblings, and contain only the following characters: [a-z0-9-_.].
2	`url`	`fuchsia.url/Url`	The child component's URL. Must be non-empty and a well-formed URL.
3	`startup`	`StartupMode`	The startup mode for the component instance.
4	`environment`	`fuchsia.component/name`	The environment assigned to this child. Must be non-empty, reference an environment defined in the containing `ComponentDecl`, and contain only the following characters: [a-z0-9-_.].
5	`on_terminate`	`OnTerminate`	The action to take if this component instance terminates unexpectedly. May be unset, in which case defaults to `NONE`.

CollectionDecl

Defined in fuchsia.sys2/collection_decl.fidl

Statically declares a component instance collection.

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	The name of the collection. Instances created in the collection are scoped to this name.
2	`durability`	`Durability`	The durability of instances in the collection.
4	`allowed_offers`	`AllowedOffers`	The kinds of offers that can target the child instances in this collection. The default value is `STATIC_ONLY`. Only components using the `dynamic_offers` restricted feature may set this field.
3	`environment`	`fuchsia.component/name`	The environment assigned to child instances in this collection. Must be non-empty, reference an environment defined in the containing `ComponentDecl`, and contain only the following characters: [a-z0-9-_.].

Component resource

Defined in fuchsia.sys2/component.fidl

A component is a unit of executable software.

This object provides the component's declaration, access to its package's content, and relevant metadata.

Ordinal Field Type Description

resolved_url

string

The resolved URL of the component. This is the canonical URL obtained by the component resolver after following redirects and resolving relative paths.

decl

fuchsia.mem/Data

Binary representation of the component's declaration (fuchsia.sys2.ComponentDecl). This information is typically obtained from the component's manifest or generated by the component resolver.

package

Package

The package that contains the component. By convention, the component's package is mapped to "/pkg" in its namespace at runtime.

This is null if the component is not represented as a package. In that case, it is the runner's responsibility to load the component's resource from the resolved_url. This mechanism is used for web applications.

Most runners, including but not limited to the builtin ELF runner, require the package's directory connection to have OPEN_RIGHT_EXECUTABLE rights in order to run the resolved component.

ComponentCrashInfo

Information stored when a thread crashes.

Ordinal	Field	Type	Description
1	`url`	`string[4096]`
2	`moniker`	`string[4096]`

ComponentDecl

Defined in fuchsia.sys2/component_decl.fidl

A component declaration.

This information is typically encoded in the component manifest (.cm file) if it has one or may be generated at runtime by a component resolver for those that don't.

Ordinal	Field	Type	Description
1	`program`	`ProgramDecl`	Information about the program to run when the component is executed. Omitted for non-executable components.
2	`uses`	`vector<UseDecl>`	List of capabilities used by the component. These consist of capabilities offered to the component that are installed in its incoming namespace. The used capabilities must be unique and non-overlapping.
3	`exposes`	`vector<ExposeDecl>`	List of capabilities exposed by the component. These consist of capabilities that are made visible to the parent. The parent may `offer` these capabilities to its children, but not `use` them. The exposed capabilities must be unique and non-overlapping.
4	`offers`	`vector<OfferDecl>`	List of capabilities offered to the component's children. These consist of capabilities that the given children may `use`, which may come from a child, the parent, or the component's own outgoing namespace. The offered capabilities must be unique and non-overlapping.
5	`capabilities`	`vector<CapabilityDecl>`	List of capabilities defined by the component.
6	`children`	`vector<ChildDecl>`	The component's statically instantiated children. The children must have unique names.
7	`collections`	`vector<CollectionDecl>`	The component's collections. The collections must have unique names.
8	`environments`	`vector<EnvironmentDecl>`	List of environments created by this component. Environments are assigned to children and control aspects of a child component's runtime.
9	`facets`	`fuchsia.data/Dictionary`	Additional metadata about the component.

CreateChildArgs resource

Defined in fuchsia.sys2/realm.fidl

Ordinal Field Type Description

numbered_handles

vector<fuchsia.process/HandleInfo>[128]

The numbered handles to pass to the component instance.

Only PA_FD and PA_USER* handles are valid arguments, and inclusion of any other handles will result in an error. This argument is only supported for components in a collection with SingleRun durability.

If the runner for the component does not support the numbered handles it is expected to close the handles.

dynamic_offers

vector<OfferDecl>[128]

Dynamic offers that will target the component instance.

Including OfferDecls in this vector will cause additional capabilities to be offered to the newly created child, beyond the OfferDecls in the parent's ComponentDecl that target the collection.

Any kind of offer (e.g., protocol, directory) can be used as a dynamic offer. Any source that would be valid for a static offer is also valid for a dynamic offer. Additionally, unlike static offers, dynamic offers can use a "sibling" dynamic child component as a source by setting the source to a ChildRef that sets the collection field.

Dynamic offers always target the newly created child component. As a result, OfferDecls in dynamic_offers must not set the target field, as its value is implied.

If either the source (that is, the component named in the source field of the OfferDecl) or the target of a dynamic offer is destroyed, the offer itself is destroyed simultaneously.

In order to set this field to a non-empty value, the collection in which the child component is being created must specify ComponentDecl.allowed_offers = STATIC_AND_DYNAMIC.

TODO(fxbug.dev/81109): Implementation is in progress.

DebugProtocolRegistration

Registers a protocol in the environment as a debug capability. This makes it available to any component in the environment that uses it with source == debug.

To learn more about protocols, see: https://fuchsia.dev/fuchsia-src/glossary#protocol

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `parent`, `self`, or `child`.
2	`source_name`	`fuchsia.component/name`	Name identifying the protocol being offered.
3	`target_name`	`fuchsia.component/name`	The name by which the capability is being offered.

DestroyedError

Defined in fuchsia.sys2/events.fidl

Error payload for Destroyed events.

Ordinal	Field	Type	Description

DestroyedPayload

Defined in fuchsia.sys2/events.fidl

Payload for Destroyed events.

Ordinal	Field	Type	Description

DirectoryDecl

Declares a directory capability backed by this component.

To learn more about directories, see: https://fuchsia.dev/fuchsia-src/glossary#directory

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	The name of this directory.
2	`source_path`	`string[1024]`	The path to the directory in the component's outgoing directory.
3	`rights`	`fuchsia.io2/Rights`	The maximum rights that can be set by a component using this directory.

DirectoryReadyError

Defined in fuchsia.sys2/events.fidl

Error payload for DirectoryReady events

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	The name of the capability.

DirectoryReadyPayload resource

Defined in fuchsia.sys2/events.fidl

Payload for DirectoryReady events

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	The name of the capability.
2	`node`	`fuchsia.io/Node`	Channel to the directory capability.

DiscoveredError

Defined in fuchsia.sys2/events.fidl

Error payload for Discovered events.

Ordinal	Field	Type	Description

DiscoveredPayload

Defined in fuchsia.sys2/events.fidl

Payload for Discovered events.

Ordinal	Field	Type	Description

EnvironmentDecl

Declares an environment which configures a realm.

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	The name of this environment.
2	`extends`	`EnvironmentExtends`	Specifies how the initial state of this environment is constructed.
3	`runners`	`vector<RunnerRegistration>`	List of runners available in this environment. This list determines the total set of runners that are available for any component in the environment to use.
4	`resolvers`	`vector<ResolverRegistration>`	List of component resolvers and the URL schemes they are registered to resolve. These registrations determine how components are resolved in the realm. If the component URL scheme does not match any of these resolvers, URL resolution is delegated to the parent environment, if this environment `extends` from `REALM`.
5	`debug_capabilities`	`vector<DebugRegistration>`	Expose capabilties to debug section when component manager allows it. These capabilities are accessible to any component in the environment with a `use` declaration with `source == debug`. Only capabilities intended to support development should be declared here, and they are only allowed if explicitly included in the component manager allowlist.
6	`stop_timeout_ms`	`uint32`	The duration in milliseconds that the component will have to stop before it is killed.

Event resource

Defined in fuchsia.sys2/events.fidl

Contains all information about a single event

Ordinal	Field	Type	Description
1	`header`	`EventHeader`	Information about the component for which this event was generated.
2	`event_result`	`EventResult`	Optional payload for some event types
3	`handler`	`Handler`	Handler for resuming from event This will be absent if this is an async event.

EventDecl

Declares an event capability which component instances may subscribe to. This type cannot be used in fuchsia.sys2.ComponentDecl. It is only used for the framework's built-in capabilities declared in fuchsia.component.internal.Config.

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	The name of this event. Must be non-empty, unique among built-in capabilities.

EventError

Defined in fuchsia.sys2/events.fidl

Corresponds to an error that occurred during a state transition.

Ordinal	Field	Type	Description
1	`description`	`string[100]`	A string describing the error that occurred. TODO(fxbug.dev/49792): We should be sending structured errors, and not simply strings. This is a placeholder pending further internal component manager refactors.
2	`error_payload`	`EventErrorPayload`	The error payload of the event if any.

EventHeader

Defined in fuchsia.sys2/events.fidl

A head providing metadata about a target component instance.

Ordinal	Field	Type	Description
1	`event_type`	`EventType`	Event type corresponding to the event
2	`moniker`	`string[4096]`	Relative moniker identifying the component instance. Relative to the scope of the event.
3	`component_url`	`fuchsia.url/Url`	URL used to resolve the component.
4	`timestamp`	`zx/time`	Time when the event occurred.

EventSubscription

Defined in fuchsia.sys2/events.fidl

Indicates the event name to subscribe to with a given event mode.

Ordinal	Field	Type	Description
1	`event_name`	`fuchsia.component/name`
2	`mode`	`EventMode`	The event mode with which to subscribe to the event names above.

ExposeDirectoryDecl

Defined in fuchsia.sys2/expose_decl.fidl

Declares a directory exposed to a component's containing realm, such as a directory exposed by the component or one of its children at runtime.

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `self` or `child`.
2	`source_name`	`fuchsia.component/name`	Name identifying the directory, by which it was presented to this component.
3	`target`	`Ref`	The destination to which the directory is exposed: either the component's realm or the framework.
4	`target_name`	`fuchsia.component/name`	The name by which the capability is being exposed.
5	`rights`	`fuchsia.io2/Rights`	The maximum rights that can be set by a component using this directory, required iff `source == self`.
6	`subdir`	`string[1024]`	The subdirectory of this directory to expose instead of the root. Optional.

ExposeProtocolDecl

Defined in fuchsia.sys2/expose_decl.fidl

Declares a protocol exposed to a component's containing realm, such as a protocol exposed by the component or one of its children at runtime.

To learn more about protocols, see: https://fuchsia.dev/fuchsia-src/glossary#protocol

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `self` or `child`.
2	`source_name`	`fuchsia.component/name`	Name identifying the protocol, by which it was presented to this component.
3	`target`	`Ref`	The destination to which the protocol is exposed: either the component's realm or the framework.
4	`target_name`	`fuchsia.component/name`	The name by which the capability is being exposed.

ExposeResolverDecl

Defined in fuchsia.sys2/expose_decl.fidl

Declares a resolver exposed to a component's containing realm, such as a resolver exposed by the component or one of its children at runtime.

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `self` or `child`.
2	`source_name`	`fuchsia.component/name`	The name of the resolver, by which it was presented to this component.
3	`target`	`Ref`	The destination to which the resolver is exposed: either the component's realm or the framework.
4	`target_name`	`fuchsia.component/name`	The name by which the capability is being exposed.

ExposeRunnerDecl

Defined in fuchsia.sys2/expose_decl.fidl

Declares a runner exposed to a component's containing realm, such as a runner exposed by the component or one of its children at runtime.

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `self` or `child`.
2	`source_name`	`fuchsia.component/name`	The name of the runner, by which it was presented to this component.
3	`target`	`Ref`	The destination to which the runner is exposed: either the component's realm or the framework.
4	`target_name`	`fuchsia.component/name`	The name by which the capability is being exposed.

ExposeServiceDecl

Defined in fuchsia.sys2/expose_decl.fidl

Declares a service exposed to a component's containing realm, such as a service exposed by the component or one of its children at runtime.

To learn more about services, see: https://fuchsia.dev/fuchsia-src/glossary#service

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `self` or `child`.
2	`source_name`	`fuchsia.component/name`	Name identifying the service, by which it was presented to this component.
3	`target`	`Ref`	The destination to which the service is exposed: either the component's realm or the framework.
4	`target_name`	`fuchsia.component/name`	The name by which the capability is being exposed.

OfferDirectoryDecl

Defined in fuchsia.sys2/offer_decl.fidl

Declares a directory offered by a component to one of its children, which may have been offered by the component's containing realm, the component itself, or one of its other children.

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `parent`, `self`, or `child`.
2	`source_name`	`fuchsia.component/name`	Name identifying the directory being offered.
3	`target`	`Ref`	Reference to the target of the capability. Must be `child` or `collection`.
4	`target_name`	`fuchsia.component/name`	The name by which the capability is being offered.
5	`rights`	`fuchsia.io2/Rights`	The maximum rights that can be set by a component using this directory, required iff `source == self`.
6	`subdir`	`string[1024]`	The subdirectory of this directory to offer instead of the root. Optional.
7	`dependency_type`	`DependencyType`	The dependency type this offer represents. A component which recieves a weak offer must support the offered capability being unavailable at any point.

OfferEventDecl

Defined in fuchsia.sys2/offer_decl.fidl

Declares an event offered by a component.

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the event. Must be `parent`.
2	`source_name`	`fuchsia.component/name`	Name of the event being offered.
3	`target`	`Ref`	Reference to the target of the event. Must be `child` or `collection`.
4	`target_name`	`fuchsia.component/name`	Name under which the event is being offered.
5	`mode`	`EventMode`	The mode offered for the event.
6	`filter`	`fuchsia.data/Dictionary`	Filter for the event. The structure of the filter depends on the event type. May be absent for some events.

OfferProtocolDecl

Defined in fuchsia.sys2/offer_decl.fidl

Declares a protocol offered by a component to one of its children, which may have been offered by the component's containing realm, the component itself, or one of its other children.

To learn more about protocols, see: https://fuchsia.dev/fuchsia-src/glossary#protocol

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `parent`, `self`, or `child`.
2	`source_name`	`fuchsia.component/name`	Name identifying the protocol being offered.
3	`target`	`Ref`	Reference to the target. Must be `child` or `collection`.
4	`target_name`	`fuchsia.component/name`	The name by which the capability is being offered.
5	`dependency_type`	`DependencyType`	The dependency type this offer represents. A component which recieves a weak offer must support the offered capability being unavailable at any point.

OfferResolverDecl

Defined in fuchsia.sys2/offer_decl.fidl

Declares a resolver capability offered by a component to one of its children, which may have been offered by the component's containing realm, the component itself, or one of its other children.

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `parent`, `self`, or `child`.
2	`source_name`	`fuchsia.component/name`	Name of the resolver being offered.
3	`target`	`Ref`	Reference to the target of the capability. Must be `child` or `collection`.
4	`target_name`	`fuchsia.component/name`	Name under which the capability is being offered.

OfferRunnerDecl

Defined in fuchsia.sys2/offer_decl.fidl

Declares a runner offered by a component to one of its children, which may have been offered by the component's containing realm, the component itself, or one of its other children.

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `parent`, `self`, or `child`.
2	`source_name`	`fuchsia.component/name`	Name of the runner being offered.
3	`target`	`Ref`	Reference to the target of the capability. Must be `child` or `collection`.
4	`target_name`	`fuchsia.component/name`	Name under which the capability is being offered.

OfferServiceDecl

Defined in fuchsia.sys2/offer_decl.fidl

Declares a service offered by a component to one of its children, which may have been offered by the component's containing realm, the component itself, or one of its other children.

To learn more about services, see: https://fuchsia.dev/fuchsia-src/glossary#service

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `parent`, `self`, or `child`.
2	`source_name`	`fuchsia.component/name`	Name identifying the service being offered.
3	`target`	`Ref`	Reference to the target. Must be `child` or `collection`.
4	`target_name`	`fuchsia.component/name`	The name under which the capability is being offered.

OfferStorageDecl

Defined in fuchsia.sys2/offer_decl.fidl

Declares a storage capability offered by a component to one of its children, such as meta storage offered by the component's containing realm or cache storage offered by the component itself.

Ordinal	Field	Type	Description
1	`source_name`	`fuchsia.component/name`	The name of the storage capability being offered
2	`source`	`Ref`	The source of the storage capability. Must be `parent` or `storage`.
3	`target`	`Ref`	Reference to the target of the capability. Must be `child` or `collection`.
4	`target_name`	`fuchsia.component/name`	The name the storage capability is being offered as

Package resource

Defined in fuchsia.sys2/package.fidl

A package is a signed collection of immutable files.

This object provides access to a package's content and relevant metadata.

Ordinal	Field	Type	Description
1	`package_url`	`string`	The URL of the package itself.
2	`package_dir`	`fuchsia.io/Directory`	The package's content directory.

ProgramDecl

Defined in fuchsia.sys2/program_decl.fidl

A program declaration.

This declaration is set by executable components to designate the runner to use and pass runner-specific program information to it.

To learn more about runners, see: https://fuchsia.dev/fuchsia-src/glossary#runner

Ordinal Field Type Description

runner

fuchsia.component/name

The name of the runner to use to run the component. Must match a RunnerRegistration in the component's environment.

This may be absent if a UseRunnerDecl is set instead.

info

fuchsia.data/Dictionary

Information about the program to run when the component is executed. The component manager provides the contents of this dictionary to the runner when executing this program.

For instance, this might contain a path to the program's executable image, or program arguments.

ProtocolDecl

Declares a protocol capability backed by this component.

To learn more about protocols, see: https://fuchsia.dev/fuchsia-src/glossary#protocol

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	The name of this protocol.
2	`source_path`	`string[1024]`	The path to the protocol in the component's outgoing directory.

PurgedError

Defined in fuchsia.sys2/events.fidl

Error payload for Purged events.

Ordinal	Field	Type	Description

PurgedPayload

Defined in fuchsia.sys2/events.fidl

Payload for Purged events.

Ordinal	Field	Type	Description

ResolvedError

Defined in fuchsia.sys2/events.fidl

Error payload for Resolved events.

Ordinal	Field	Type	Description

ResolvedPayload

Defined in fuchsia.sys2/events.fidl

Payload for Resolved events.

Ordinal	Field	Type	Description

ResolverDecl

Declares a resolver which is responsible for resolving component URLs to actual components. See fuchsia.sys2.ComponentResolver for the protocol resolvers are expected to implement.

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	The name of this resolver. Must be non-empty, unique among resolvers declared in the same `ComponentDecl`.
2	`source_path`	`string[1024]`	The path to the resolver protocol in the component's outgoing directory

ResolverRegistration

A mapping of URL scheme to resolver name.

Ordinal	Field	Type	Description
1	`resolver`	`fuchsia.component/name`	The name of the resolver.
2	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `parent`, `self`, or `child`.
3	`scheme`	`fuchsia.component/url_scheme`	The URL scheme the resolver is registered to handle. Only one resolver may be registered to a particular URL scheme. The URL scheme must start with a lowercase ASCII letter (a-z), and may contain lowercase ASCII letters, digits, `+`, `-`, and `.`.

RunnerDecl

Declares a runner capability backed by a service.

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	The name of this runner. Must be non-empty, unique among runners declared in the same `ComponentDecl`.
2	`source_path`	`string[1024]`	The path to the runner protocol in the component's outgoing directory.

RunnerRegistration

A repository of the runners available in an environment.

Ordinal	Field	Type	Description
1	`source_name`	`fuchsia.component/name`	The name of the runner capability as it's exposed to, offered, or defined by this component.
2	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `parent`, `self`, or `child`.
3	`target_name`	`fuchsia.component/name`	The name by which the runner is made available in this environment.

RunningError

Defined in fuchsia.sys2/events.fidl

Error payload for Running events.

Ordinal	Field	Type	Description
1	`started_timestamp`	`zx/time`	Time when the component started.

RunningPayload

Defined in fuchsia.sys2/events.fidl

Payload for Running events.

Ordinal	Field	Type	Description
1	`started_timestamp`	`zx/time`	Time when the component started.

ServiceDecl

Declares a service capability backed by this component.

To learn more about services, see: https://fuchsia.dev/fuchsia-src/glossary#service

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	The name of this service.
2	`source_path`	`string[1024]`	The path to the service in the component's outgoing directory.

StartedError

Defined in fuchsia.sys2/events.fidl

Error payload for Started events.

Ordinal	Field	Type	Description

StartedPayload

Defined in fuchsia.sys2/events.fidl

Payload for Started events.

Ordinal	Field	Type	Description

StoppedError

Defined in fuchsia.sys2/events.fidl

Error payload for Stopped events.

Ordinal	Field	Type	Description

StoppedPayload

Defined in fuchsia.sys2/events.fidl

Payload for Stopped events.

Ordinal	Field	Type	Description
1	`status`	`zx/status`	The epitaph set on the fuchsia.component.runner/ComponentController protocol channel. This is the exit status of the component. The possible status values and their meaning are described in the definition of the ComponentController protocol.

StorageDecl

Declares a storage capability backed by a directory from which data, cache, or meta storage can be offered.

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	The name of this storage
2	`source`	`Ref`	The provider of the backing directory capability relative to the component itself. Must be `parent`, `self`, or `child`.
3	`backing_dir`	`fuchsia.component/name`	The name of the directory capability from `source` that backs the storage.
4	`subdir`	`string[1024]`	The subdirectory of the source directory that will back the storage
5	`storage_id`	`StorageId`	This enum determines how to key a component's isolated storage directory. Each option corresponds to a different key'ing strategy. This field is required.

UseDirectoryDecl

Defined in fuchsia.sys2/use_decl.fidl

Declares a directory used by a component, which was offered to it.

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the directory relative to the component itself. Must be `parent` or `framework`.
2	`source_name`	`fuchsia.component/name`	Name identifying the directory, by which it was presented to this component.
3	`target_path`	`string[1024]`	The path where the capability should be installed in the component's namespace. Must be an absolute path starting with /.
4	`rights`	`fuchsia.io2/Rights`	The rights required by the component to use this directory.
5	`subdir`	`string[1024]`	The subdirectory of this directory to use instead of the root. Optional.
6	`dependency_type`	`DependencyType`	The dependency type this use represents. A component which offers a capability to a child from itself and uses a capability from the same child, must mark the dependency as `weak`. A `weak` dependency implies that the capability may become unavailable at any point. Taking a strong dependency on a child's capability will cause this the child to shut down before its parent. When using a weak dependency, the parent shuts down before the child.

UseEventDecl

Defined in fuchsia.sys2/use_decl.fidl

Declares an event used by a component, which was offered to it.

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the event. Must be \|realm\| or \|framework\|.
2	`source_name`	`fuchsia.component/name`	Name identifying the event which was presented to this component.
3	`target_name`	`fuchsia.component/name`	The name which the component will use to refer to this event.
4	`filter`	`fuchsia.data/Dictionary`	Filter for the event. The structure of the filter depends on the event type. May be absent for some events.
5	`mode`	`EventMode`	The mode that the event can use.
6	`dependency_type`	`DependencyType`	The dependency type this use represents. A component which offers a capability to a child from itself and uses a capability from the same child, must mark the dependency as `weak`. A `weak` dependency implies that the capability may become unavailable at any point. Taking a strong dependency on a child's capability will cause this the child to shut down before its parent. When using a weak dependency, the parent shuts down before the child.

UseEventStreamDecl

Defined in fuchsia.sys2/use_decl.fidl

Declares a static EventStream used by a component.

Ordinal	Field	Type	Description
1	`name`	`fuchsia.component/name`	The name of the event stream.
2	`subscriptions`	`vector<EventSubscription>[100]`	The set of events to which this EventStream is subscribed. Note: This vector must be non-empty.

UseProtocolDecl

Defined in fuchsia.sys2/use_decl.fidl

Declares a protocol used by a component, which was offered to it.

A protocol is a service with a single instance, provided by a single FIDL protocol.

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the protocol relative to the component itself. Must be `parent`, `framework`, `debug` or `capability`.
2	`source_name`	`fuchsia.component/name`	Name identifying the protocol, by which it was presented to this component.
3	`target_path`	`string[1024]`	The path where the capability should be installed in the component's namespace. Must be an absolute path starting with /.
4	`dependency_type`	`DependencyType`	The dependency type this use represents. A component which offers a capability to a child from itself and uses a capability from the same child, must mark the dependency as `weak`. A `weak` dependency implies that the capability may become unavailable at any point. Taking a strong dependency on a child's capability will cause this the child to shut down before its parent. When using a weak dependency, the parent shuts down before the child.

UseServiceDecl

Defined in fuchsia.sys2/use_decl.fidl

Declares a service used by a component, which was offered to it.

To learn more about services, see: https://fuchsia.dev/fuchsia-src/glossary#service

Ordinal	Field	Type	Description
1	`source`	`Ref`	The provider of the service relative to the component itself. Must be `parent` or `framework`.
2	`source_name`	`fuchsia.component/name`	Name identifying the service, by which it was presented to this component.
3	`target_path`	`string[1024]`	The path where the capability should be installed in the component's namespace. Must be an absolute path starting with /.
4	`dependency_type`	`DependencyType`	The dependency type this use represents. A component which offers a capability to a child from itself and uses a capability from the same child, must mark the dependency as `weak`. A `weak` dependency implies that the capability may become unavailable at any point. Taking a strong dependency on a child's capability will cause this the child to shut down before its parent. When using a weak dependency, the parent shuts down before the child.

UseStorageDecl

Defined in fuchsia.sys2/use_decl.fidl

Declares storage used by a component, which was offered to it.

Ordinal Field Type Description

source_name

fuchsia.component/name

Name identifying the storage, by which it was presented to this component.

target_path

string[1024]

The path where the capability should be installed in the component's namespace.

Must be an absolute path starting with /.

WorkRequest

Parameters for a new piece of work to be scheduled.

Ordinal	Field	Type	Description
1	`start`	`Start`	Time when corresponding work item should be first scheduled.
2	`period`	`zx/duration`	Delay between repeated schedulings of corresponding work item. This is left unspecified for one-shot work that should not repeat. Repeating work items are rescheduled indefinitely until it is canceled.

UNIONS

CapabilityDecl flexible

Declares a capability defined by this component.

Ordinal
Variant	Type	Description
1	`service`	`ServiceDecl`
2	`protocol`	`ProtocolDecl`
3	`directory`	`DirectoryDecl`
4	`storage`	`StorageDecl`
5	`runner`	`RunnerDecl`
6	`resolver`	`ResolverDecl`
7	`event`	`EventDecl`

ComponentResolver_Resolve_Result strict resource

Ordinal
Variant	Type	Description
1	`response`	`ComponentResolver_Resolve_Response`
2	`err`	`ResolverError`

CrashIntrospect_FindComponentByThreadKoid_Result strict

Ordinal
Variant	Type	Description
1	`response`	`CrashIntrospect_FindComponentByThreadKoid_Response`
2	`err`	`fuchsia.component/Error`

DebugRegistration flexible

Declares a capability registered in the debug section of an environment.

Ordinal
Variant	Type	Description
1	`protocol`	`DebugProtocolRegistration`

EventErrorPayload flexible

Defined in fuchsia.sys2/events.fidl

Encapsulates additional data for some event errors.

Ordinal
Variant	Type	Description
1	`capability_requested`	`CapabilityRequestedError`	Payload for CapabilityRequested events
2	`capability_routed`	`CapabilityRoutedError`	Payload for CapabilityRouted events
3	`purged`	`PurgedError`	Payload for Purged events.
4	`directory_ready`	`DirectoryReadyError`	Payload for DirectoryReady events
5	`discovered`	`DiscoveredError`	Payload for Discovered events.
6	`destroyed`	`DestroyedError`	Payload for Destroyed events.
7	`resolved`	`ResolvedError`	Payload for Resolved events
8	`running`	`RunningError`	Payload for Running events
9	`started`	`StartedError`	Payload for Started events
10	`stopped`	`StoppedError`	Payload for Stopped events

EventPayload flexible resource

Defined in fuchsia.sys2/events.fidl

Encapsulates additional data/protocols for some event types.

Ordinal
Variant	Type	Description
1	`capability_requested`	`CapabilityRequestedPayload`	Payload for CapabilityRequested events
2	`capability_routed`	`CapabilityRoutedPayload`	Payload for CapabilityRouted events
3	`purged`	`PurgedPayload`	Payload for Purged events.
4	`directory_ready`	`DirectoryReadyPayload`	Payload for DirectoryReady events
5	`discovered`	`DiscoveredPayload`	Payload for Discovered events.
6	`destroyed`	`DestroyedPayload`	Payload for Destroyed events.
7	`resolved`	`ResolvedPayload`	Payload for Resolved events
8	`running`	`RunningPayload`	Payload for Running events
9	`started`	`StartedPayload`	Payload for Started events
10	`stopped`	`StoppedPayload`	Payload for Stopped events

EventResult flexible resource

Defined in fuchsia.sys2/events.fidl

Describes the result of a state transition.

Ordinal
Variant	Type	Description
1	`payload`	`EventPayload`	The payload of the event if the state transition described by the event succeeds.
2	`error`	`EventError`	The error that caused the state transition described by the event to fail.

EventSource_Subscribe_Result strict

Defined in fuchsia.sys2/events.fidl

Ordinal
Variant	Type	Description
1	`response`	`EventSource_Subscribe_Response`
2	`err`	`fuchsia.component/Error`

EventSource_TakeStaticEventStream_Result strict resource

Defined in fuchsia.sys2/events.fidl

Ordinal
Variant	Type	Description
1	`response`	`EventSource_TakeStaticEventStream_Response`
2	`err`	`fuchsia.component/Error`

ExposeDecl flexible

Defined in fuchsia.sys2/expose_decl.fidl

Declares a capability exposed to either a component's containing realm or to the framework. For example, a legacy service exposed by the component at runtime.

Ordinal
Variant	Type	Description
1	`service`	`ExposeServiceDecl`
2	`protocol`	`ExposeProtocolDecl`
3	`directory`	`ExposeDirectoryDecl`
4	`runner`	`ExposeRunnerDecl`
5	`resolver`	`ExposeResolverDecl`

LifecycleController_Bind_Result strict

Defined in fuchsia.sys2/lifecycle_controller.fidl

Ordinal
Variant	Type	Description
1	`response`	`LifecycleController_Bind_Response`
2	`err`	`fuchsia.component/Error`

LifecycleController_CreateChild_Result strict

Defined in fuchsia.sys2/lifecycle_controller.fidl

Ordinal
Variant	Type	Description
1	`response`	`LifecycleController_CreateChild_Response`
2	`err`	`fuchsia.component/Error`

LifecycleController_DestroyChild_Result strict

Defined in fuchsia.sys2/lifecycle_controller.fidl

Ordinal
Variant	Type	Description
1	`response`	`LifecycleController_DestroyChild_Response`
2	`err`	`fuchsia.component/Error`

LifecycleController_Resolve_Result strict

Defined in fuchsia.sys2/lifecycle_controller.fidl

Ordinal
Variant	Type	Description
1	`response`	`LifecycleController_Resolve_Response`
2	`err`	`fuchsia.component/Error`

LifecycleController_Stop_Result strict

Defined in fuchsia.sys2/lifecycle_controller.fidl

Ordinal
Variant	Type	Description
1	`response`	`LifecycleController_Stop_Response`
2	`err`	`fuchsia.component/Error`

OfferDecl flexible

Defined in fuchsia.sys2/offer_decl.fidl

Declares a capability offered by a component to one of its children, which may have been offered by the component's containing realm, the component itself, or one of its other children.

Ordinal
Variant	Type	Description
1	`service`	`OfferServiceDecl`
2	`protocol`	`OfferProtocolDecl`
3	`directory`	`OfferDirectoryDecl`
4	`storage`	`OfferStorageDecl`
5	`runner`	`OfferRunnerDecl`
6	`resolver`	`OfferResolverDecl`
7	`event`	`OfferEventDecl`

Realm_CreateChild_Result strict

Defined in fuchsia.sys2/realm.fidl

Ordinal
Variant	Type	Description
1	`response`	`Realm_CreateChild_Response`
2	`err`	`fuchsia.component/Error`

Realm_DestroyChild_Result strict

Defined in fuchsia.sys2/realm.fidl

Ordinal
Variant	Type	Description
1	`response`	`Realm_DestroyChild_Response`
2	`err`	`fuchsia.component/Error`

Realm_ListChildren_Result strict

Defined in fuchsia.sys2/realm.fidl

Ordinal
Variant	Type	Description
1	`response`	`Realm_ListChildren_Response`
2	`err`	`fuchsia.component/Error`

Realm_OpenExposedDir_Result strict

Defined in fuchsia.sys2/realm.fidl

Ordinal
Variant	Type	Description
1	`response`	`Realm_OpenExposedDir_Response`
2	`err`	`fuchsia.component/Error`

Ref flexible

A reference to a capability source or destination relative to this component.

Ordinal
Variant	Type	Description
1	`parent`	`ParentRef`
2	`self`	`SelfRef`
3	`child`	`ChildRef`
4	`collection`	`CollectionRef`
5	`framework`	`FrameworkRef`
6	`capability`	`CapabilityRef`
7	`debug`	`DebugRef`

Start flexible

Different ways to specify when to schedule a work item for the first time.

Ordinal
Variant	Type	Description
1	`delay`	`zx/duration`	A non-negative delay to wait before scheduling work.
2	`monotonic_time`	`zx/time`	A fixed point in time to start scheduling work, interpreted like `ZX_CLOCK_MONOTONIC`: number of nanoseconds since the system was powered on.

StorageAdmin_DeleteComponentStorage_Result strict

Ordinal
Variant	Type	Description
1	`response`	`StorageAdmin_DeleteComponentStorage_Response`
2	`err`	`fuchsia.component/Error`

StorageAdmin_ListStorageInRealm_Result strict

Ordinal
Variant	Type	Description
1	`response`	`StorageAdmin_ListStorageInRealm_Response`
2	`err`	`fuchsia.component/Error`

StorageAdmin_OpenComponentStorageById_Result strict

Ordinal
Variant	Type	Description
1	`response`	`StorageAdmin_OpenComponentStorageById_Response`
2	`err`	`fuchsia.component/Error`

UseDecl flexible

Defined in fuchsia.sys2/use_decl.fidl

Declares a capability used by a component, which was offered to it.

Ordinal
Variant	Type	Description
1	`service`	`UseServiceDecl`
2	`protocol`	`UseProtocolDecl`
3	`directory`	`UseDirectoryDecl`
4	`storage`	`UseStorageDecl`
5	`event`	`UseEventDecl`
6	`event_stream`	`UseEventStreamDecl`

WorkSchedulerControl_GetBatchPeriod_Result strict

Ordinal
Variant	Type	Description
1	`response`	`WorkSchedulerControl_GetBatchPeriod_Response`
2	`err`	`fuchsia.component/Error`

WorkSchedulerControl_SetBatchPeriod_Result strict

Ordinal
Variant	Type	Description
1	`response`	`WorkSchedulerControl_SetBatchPeriod_Response`
2	`err`	`fuchsia.component/Error`

WorkScheduler_CancelWork_Result strict

Ordinal
Variant	Type	Description
1	`response`	`WorkScheduler_CancelWork_Response`
2	`err`	`fuchsia.component/Error`

WorkScheduler_ScheduleWork_Result strict

Ordinal
Variant	Type	Description
1	`response`	`WorkScheduler_ScheduleWork_Response`
2	`err`	`fuchsia.component/Error`

Worker_DoWork_Result strict