fuchsia.sys2

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

Name	Type

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

ChildRef

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

Name	Type	Description	Default
`name`	`fuchsia.component/child_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/collection_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.

Name	Type	Description	Default
`name`	`fuchsia.component/collection_name`		No default

Entry

Defined in fuchsia.sys2/object.fidl

A key/value pair in an Object.

Name	Type	Description	Default
`key`	`string`		No default
`value`	`Value?`		No default

EventSource_Subscribe_Response

Defined in fuchsia.sys2/events.fidl

Name	Type	Description	Default

FrameworkRef

A reference to the component framework itself.

Name	Type	Description	Default

Object

Defined in fuchsia.sys2/object.fidl

An object is a sequence of key/value pairs. Keys must be unique and sorted in lexicographically increasing order.

Name	Type	Description	Default
`entries`	`vector<Entry>`		No default

RealmRef

A reference to a component’s containing realm, i.e. the parent component.

Name	Type	Description	Default

Realm_BindChild_Response

Defined in fuchsia.sys2/realm.fidl

Name	Type	Description	Default

Realm_CreateChild_Response

Defined in fuchsia.sys2/realm.fidl

Name	Type	Description	Default

Realm_DestroyChild_Response

Defined in fuchsia.sys2/realm.fidl

Name	Type	Description	Default

Realm_ListChildren_Response

Defined in fuchsia.sys2/realm.fidl

Name	Type	Description	Default

SelfRef

A reference to the component itself.

Name	Type	Description	Default

StorageRef

A reference to one of the component's storage sections.

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

Vector

Defined in fuchsia.sys2/object.fidl

A vector is a sequence of values.

Name	Type	Description	Default
`values`	`vector<Value>`		No default

WorkSchedulerControl_GetBatchPeriod_Response

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

WorkSchedulerControl_SetBatchPeriod_Response

Name	Type	Description	Default

WorkScheduler_CancelWork_Response

Name	Type	Description	Default

WorkScheduler_ScheduleWork_Response

Name	Type	Description	Default

Worker_DoWork_Response

Name	Type	Description	Default

ENUMS

DependencyType

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_FOR_MIGRATION`	`2`	A weak dependency specifically used to mark cyclic dependencies of migrated components. Components that use a weak dependency must support the dependency being unavailable at arbitrary times.

Durability

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.

EnvironmentExtends

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`.

EventType

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_READY`	`1`	A capability exposed to the framework by a component is available.
`CAPABILITY_REQUESTED`	`2`	A capability provided by this component has been requested. The event payload carries the request channel.
`CAPABILITY_ROUTED`	`3`	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.
`DESTROYED`	`4`	An instance was destroyed successfully. The instance is stopped and no longer exists in the parent's realm.
`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.
`MARKED_FOR_DESTRUCTION`	`6`	Destruction of an instance has begun. The instance may/may not be stopped by this point. The instance still exists in the parent's realm but will soon be removed. TODO(fxb/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 Destroyed.
`RUNNING`	`10`	If requested, this event is dispatched on subscription and indicates that the instance has already started and is still running.

StartupMode

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.

StorageType

Type: uint32

Defined in fuchsia.sys2/storage_decl.fidl

The type of storage offered by this component.

Name	Value	Description
`DATA`	`1`	General data storage.
`CACHE`	`2`	Cache storage that may be deleted at any time by the system.
`META`	`3`	Meta storage that will be used by component manager to persist metadata and other information about the component

TABLES

AboveRootCapability

Defined in fuchsia.sys2/events.fidl

Describes a capability provided by component manager at the realm above the root.

Ordinal	Name	Type	Description

CapabilityReadyError

Defined in fuchsia.sys2/events.fidl

Error payload for CapabilityReady events

Ordinal	Name	Type	Description
1	`path`	`string[1024]`	The path of the capability.

CapabilityReadyPayload

Defined in fuchsia.sys2/events.fidl

Payload for CapabilityReady events

Ordinal	Name	Type	Description
1	`path`	`string[1024]`	The path of the capability.
2	`node`	`fuchsia.io/Node`	Channel to the node exposed by the event source at `path`.

CapabilityRequestedError

Defined in fuchsia.sys2/events.fidl

Error payload for CapabilityRequested events

Ordinal	Name	Type	Description
1	`path`	`string[50]`	Identifier of capability being requested. For a path-based capability, this is the path. For a runner capability, this is the name.

CapabilityRequestedPayload

Defined in fuchsia.sys2/events.fidl

Payload for CapabilityRequested events

Ordinal	Name	Type	Description
1	`path`	`string[1024]`	The path 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	Name	Type	Description
1	`capability_id`	`string[50]`	Identifier of capability being requested. For a path-based capability, this is the path. For a runner capability, this is the name.

CapabilityRoutedPayload

Defined in fuchsia.sys2/events.fidl

Payload for CapabilityRouted events

Ordinal	Name	Type	Description
1	`routing_protocol`	`RoutingProtocol`	Allows setting a capability provider for CapabilityRouted events This will not be available with an async event.
2	`capability_id`	`string[50]`	Identifier of capability being requested. For a path-based capability, this is the path. For a runner capability, this is the name.
3	`source`	`CapabilitySource`	Source of the capability that needs to be routed.

ChildDecl

Defined in fuchsia.sys2/child_decl.fidl

Statically declares a child component instance.

Ordinal	Name	Type	Description
1	`name`	`fuchsia.component/child_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/environment_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-_.].

CollectionDecl

Defined in fuchsia.sys2/collection_decl.fidl

Statically declares a component instance collection.

Ordinal Name Type Description

name

fuchsia.component/collection_name

The name of the collection. Instances created in the collection are scoped to this name.

durability

Durability

The durability of instances in the collection.

environment

fuchsia.component/environment_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

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 Name 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

ComponentDecl

The component's declaration. 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.

ComponentCapability

Defined in fuchsia.sys2/events.fidl

Describes a capability provided by a component

Ordinal	Name	Type	Description
1	`source_moniker`	`string[4096]`	The moniker of the instance that is providing this capability.

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	Name	Type	Description
1	`program`	`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 component runner when executing the program. Each component runner can freely define the contents of this dictionary as needed. The system's default runner understands the following entries: "binary": string The path of the executable relative to the root of the package. Typically an ELF binary. "args": vector of strings The command-line arguments to provide to the executable at runtime. "env": dictionary of strings The environment variables to provide to the executable at runtime. Other runners may define different entries.
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 containing realm. 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 containing realm, or the component's own outgoing namespace. The offered capabilities must be unique and non-overlapping.
5	`facets`	`Object`	Additional metadata about 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	`storage`	`vector<StorageDecl>`	List of storage capabilities created by this component. Storage capabilities can be offered to children.
9	`runners`	`vector<RunnerDecl>`	List of runner capabilities created by this component. Runner capabilities can be exposed to the parent's realm or offered to children.
10	`environments`	`vector<EnvironmentDecl>`	List of environments created by this component. Environments are assigned to children and control aspects of a child component's runtime.
11	`resolvers`	`vector<ResolverDecl>`	List of resolver capabilities created by this component. A component can: "expose" a resolver capability to its realm, "offer" a resolver capability to its children, register a resolver in an environment. A component cannot "use" a resolver capability directly. Component manager uses a resolver capability on behalf of a component when that component's environment contains the resolver capability.

ComponentDescriptor

Defined in fuchsia.sys2/events.fidl

A descriptor providing metadata about a target component instance.

Ordinal	Name	Type	Description
1	`moniker`	`string[4096]`	Relative moniker identifying the component instance. Relative to the scope of the event.
2	`component_url`	`fuchsia.url/Url`	URL used to resolve the component.

EnvironmentDecl

Declares an environment which configures a realm.

Ordinal	Name	Type	Description
1	`name`	`fuchsia.component/environment_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	`stop_timeout_ms`	`uint32`	The duration in milliseconds that the component will have to stop before it is killed.

Event

Defined in fuchsia.sys2/events.fidl

Contains all information about a single event

Ordinal	Name	Type	Description
1	`event_type`	`EventType`	Event type corresponding to the event
2	`descriptor`	`ComponentDescriptor`	Information about the component for which this event was generated.
3	`handler`	`Handler`	Handler for resuming from event This will be absent if this is an async event.
4	`event_result`	`EventResult`	Optional payload for some event types
5	`timestamp`	`zx/time`	Time when the event occurred.

EventError

Defined in fuchsia.sys2/events.fidl

Corresponds to an error that occurred during a state transition.

Ordinal	Name	Type	Description
1	`description`	`string[100]`	A string describing the error that occurred. TODO(fxb/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.

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	Name	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `self` or `child`.
2	`source_path`	`string[1024]`	Path 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_path`	`string[1024]`	The path by which the capability is being exposed. Must be an absolute path starting with /.
5	`rights`	`fuchsia.io2/Rights`	The rights to expose this directory with, 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 legacy service exposed to a component's containing realm, such as a legacy service exposed by the component or one of its children at runtime.

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

Ordinal	Name	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `self` or `child`.
2	`source_path`	`string[1024]`	Path identifying the legacy service, by which it was presented to this component.
3	`target`	`Ref`	The destination to which the legacy service is exposed: either the component's realm or the framework.
4	`target_path`	`string[1024]`	The path by which the capability is being exposed. Must be an absolute path starting with /.

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	Name	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/resolver_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/resolver_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	Name	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/runner_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/runner_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	Name	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `self` or `child`.
2	`source_path`	`string[1024]`	Path identifying the service, by which it was presented to this component. Must be an absolute path starting with /.
3	`target`	`Ref`	The destination to which the service is exposed: either the component's realm or the framework.
4	`target_path`	`string[1024]`	The path by which the capability is being exposed. Must be an absolute path starting with /.

FrameworkCapability

Defined in fuchsia.sys2/events.fidl

Describes a capability provided by the framework, scoped to a realm.

Ordinal	Name	Type	Description
1	`scope_moniker`	`string[4096]`	The moniker of the instance that this capability is scoped to.

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	Name	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `realm`, `self`, or `child`.
2	`source_path`	`string[1024]`	Path identifying the directory being offered.
3	`target`	`Ref`	Reference to the target of the capability. Must be `child` or `collection`.
4	`target_path`	`string[1024]`	The path under which the capability is being offered. Must be an absolute path starting with /.
5	`rights`	`fuchsia.io2/Rights`	The rights this directory should be offered with, 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	Name	Type	Description
1	`source`	`Ref`	The provider of the event. Must be `realm`.
2	`source_name`	`fuchsia.component/event_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/resolver_name`	Name under which the event is being offered.
5	`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 legacy 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.

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

Ordinal	Name	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `realm`, `self`, or `child`.
2	`source_path`	`string[1024]`	Path identifying the legacy service being offered.
3	`target`	`Ref`	Reference to the target. Must be `child` or `collection`.
4	`target_path`	`string[1024]`	The path under which the capability is being offered. Must be an absolute path starting with /.
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	Name	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `realm`, `self`, or `child`.
2	`source_name`	`fuchsia.component/resolver_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/resolver_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	Name	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `realm`, `self`, or `child`.
2	`source_name`	`fuchsia.component/runner_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/runner_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	Name	Type	Description
1	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `realm`, `self`, or `child`.
2	`source_path`	`string[1024]`	Path identifying the service being offered. Must be an absolute path starting with /.
3	`target`	`Ref`	Reference to the target. Must be `child` or `collection`.
4	`target_path`	`string[1024]`	The path under which the capability is being offered. Must be an absolute path starting with /.

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	Name	Type	Description
1	`type`	`StorageType`	The type of storage being offered.
2	`source`	`Ref`	The source of the storage capability. Must be `realm` or `storage`.
3	`target`	`Ref`	Reference to the target of the capability. Must be `child` or `collection`.

Package

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

ResolverDecl

Defined in fuchsia.sys2/resolver_decl.fidl

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	Name	Type	Description
1	`name`	`fuchsia.component/resolver_name`	The name of this resolver. Must be non-empty, unique among resolvers declared in the same `ComponentDecl`, and contain only the following characters: [a-z0-9-_.].
2	`source_path`	`string[1024]`	The path of the capability in the declaring component's namespace.

ResolverRegistration

A mapping of URL scheme to resolver name.

Ordinal	Name	Type	Description
1	`resolver`	`fuchsia.component/resolver_name`	The name of the resolver.
2	`source`	`Ref`	The provider of the capability relative to the component itself. Must be `realm`, `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

Defined in fuchsia.sys2/runner_decl.fidl

Declares a runner capability backed by a service.

Ordinal	Name	Type	Description
1	`name`	`fuchsia.component/runner_name`	The name of this runner.
2	`source`	`Ref`	The provider of the underlying service relative to the component itself. Must be `realm`, `self`, or `child`.
3	`source_path`	`string[1024]`	The path of the capability within the specified source.

RunnerRegistration

A repository of the runners available in an environment.

Ordinal	Name	Type	Description
1	`source_name`	`fuchsia.component/runner_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 `realm`, `self`, or `child`.
3	`target_name`	`fuchsia.component/runner_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	Name	Type	Description
1	`started_timestamp`	`zx/time`	Time when the component started.

RunningPayload

Defined in fuchsia.sys2/events.fidl

Payload for Running events.

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

StorageDecl

Defined in fuchsia.sys2/storage_decl.fidl

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

Ordinal	Name	Type	Description
1	`name`	`string[100]`	The name of this storage
2	`source`	`Ref`	The provider of the underlying directory capability relative to the component itself. Must be `realm`, `self`, or `child`.
3	`source_path`	`string[1024]`	The incoming path to the directory capability. If "source == SELF", this is a path in the component's outgoing directory. Otherwise, it is the path by which the capability was presented to the component.

UseDirectoryDecl

Defined in fuchsia.sys2/use_decl.fidl

Declares a directory used by a component, which was offered to the component's environment.

Ordinal	Name	Type	Description
1	`source`	`Ref`	The provider of the directory relative to the component itself. Must be `realm` or `framework`.
2	`source_path`	`string[1024]`	Path 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.

UseEventDecl

Defined in fuchsia.sys2/use_decl.fidl

Declares an event used by a component.

Ordinal	Name	Type	Description
1	`source`	`Ref`	The provider of the event. Must be \|realm\| or \|framework\|.
2	`source_name`	`fuchsia.component/event_name`	Name identifying the event which was presented to this component.
3	`target_name`	`fuchsia.component/event_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.

UseEventStreamDecl

Defined in fuchsia.sys2/use_decl.fidl

Declares a static EventStream used by a component.

Ordinal Name Type Description

target_path

string[1024]

The path where the EventStream protocol will be served.

Must be an absolute path starting with /.

events

vector<string>[100]

The set of event names to which this EventStream is subscribed. Note: This vector must be non-empty.

UseProtocolDecl

Defined in fuchsia.sys2/use_decl.fidl

Declares a legacy service used by a component, which was offered to the component's environment.

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

Ordinal Name Type Description

source

Ref

The provider of the legacy service relative to the component itself. Must be realm or framework.

source_path

string[1024]

Path identifying the legacy service, 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 /.

UseRunnerDecl

Defined in fuchsia.sys2/use_decl.fidl

Declares a runner used by a component, which was offered to the component's environment.

Ordinal	Name	Type	Description
1	`source_name`	`fuchsia.component/runner_name`	The name of the runner, as it was presented to this component by the realm.

UseServiceDecl

Defined in fuchsia.sys2/use_decl.fidl

Declares a service used by a component, which was offered to the component's environment.

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

Ordinal Name Type Description

source

Ref

The provider of the service relative to the component itself. Must be realm or framework.

source_path

string[1024]

Path identifying the service, by which it was presented to this component.

Must be an absolute path starting with /.

target_path

string[1024]

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

Must be an absolute path starting with /.

UseStorageDecl

Defined in fuchsia.sys2/use_decl.fidl

Declares storage used by a component, which was offered to the component's environment.

Ordinal Name Type Description

type

StorageType

Type of storage used by the component.

target_path

string[1024]

The path where the capability should be installed in the component's namespace. Must not be set if type is META.

Must be an absolute path starting with /.

WorkRequest

Parameters for a new piece of work to be scheduled.

Ordinal	Name	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

CapabilitySource

Defined in fuchsia.sys2/events.fidl

Describes the source of a routed capability.

Name	Type	Description
`component`	`ComponentCapability`	The capability is provided by another component.
`framework`	`FrameworkCapability`	The capability is provided by the framework and is scoped to a realm.
`above_root`	`AboveRootCapability`	The capability is provided by realm above the root, which is component manager itself.

EventErrorPayload

Defined in fuchsia.sys2/events.fidl

Encapsulates additional data for some event errors.

Name	Type	Description
`capability_ready`	`CapabilityReadyError`	Payload for CapabilityReady events
`capability_requested`	`CapabilityRequestedError`	Payload for CapabilityRequested events
`capability_routed`	`CapabilityRoutedError`	Payload for CapabilityRouted events
`running`	`RunningError`	Payload for Running events

EventPayload

Defined in fuchsia.sys2/events.fidl

Encapsulates additional data/protocols for some event types.

Name	Type	Description
`capability_ready`	`CapabilityReadyPayload`	Payload for CapabilityReady events
`capability_requested`	`CapabilityRequestedPayload`	Payload for CapabilityRequested events
`capability_routed`	`CapabilityRoutedPayload`	Payload for CapabilityRouted events
`running`	`RunningPayload`	Payload for Running events

EventResult

Defined in fuchsia.sys2/events.fidl

Describes the result of a state transition.

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

EventSource_Subscribe_Result

Defined in fuchsia.sys2/events.fidl

Name	Type	Description
`response`	`EventSource_Subscribe_Response`
`err`	`fuchsia.component/Error`

ExposeDecl

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.

Name	Type	Description
`service`	`ExposeServiceDecl`
`protocol`	`ExposeProtocolDecl`
`directory`	`ExposeDirectoryDecl`
`runner`	`ExposeRunnerDecl`
`resolver`	`ExposeResolverDecl`

OfferDecl

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.

Name	Type	Description
`service`	`OfferServiceDecl`
`protocol`	`OfferProtocolDecl`
`directory`	`OfferDirectoryDecl`
`storage`	`OfferStorageDecl`
`runner`	`OfferRunnerDecl`
`resolver`	`OfferResolverDecl`
`event`	`OfferEventDecl`

Realm_BindChild_Result

Defined in fuchsia.sys2/realm.fidl

Name	Type	Description
`response`	`Realm_BindChild_Response`
`err`	`fuchsia.component/Error`

Realm_CreateChild_Result

Defined in fuchsia.sys2/realm.fidl

Name	Type	Description
`response`	`Realm_CreateChild_Response`
`err`	`fuchsia.component/Error`

Realm_DestroyChild_Result

Defined in fuchsia.sys2/realm.fidl

Name	Type	Description
`response`	`Realm_DestroyChild_Response`
`err`	`fuchsia.component/Error`

Realm_ListChildren_Result

Defined in fuchsia.sys2/realm.fidl

Name	Type	Description
`response`	`Realm_ListChildren_Response`
`err`	`fuchsia.component/Error`

Ref

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

Name	Type	Description
`realm`	`RealmRef`
`self`	`SelfRef`
`child`	`ChildRef`
`collection`	`CollectionRef`
`storage`	`StorageRef`
`framework`	`FrameworkRef`

Start

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

Name	Type	Description
`delay`	`zx/duration`	A non-negative delay to wait before scheduling work.
`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.

UseDecl

Defined in fuchsia.sys2/use_decl.fidl

Declares a capability used by a component, which was offered to the component's environment.

Name	Type	Description
`service`	`UseServiceDecl`
`protocol`	`UseProtocolDecl`
`directory`	`UseDirectoryDecl`
`storage`	`UseStorageDecl`
`runner`	`UseRunnerDecl`
`event`	`UseEventDecl`
`event_stream`	`UseEventStreamDecl`

Value

Defined in fuchsia.sys2/object.fidl

A value is a boolean, integer, float, string, vector, or object.

Name	Type	Description
`bit`	`bool`
`inum`	`int64`
`fnum`	`float64`
`str`	`string`
`vec`	`Vector`
`obj`	`Object`

WorkSchedulerControl_GetBatchPeriod_Result

Name	Type	Description
`response`	`WorkSchedulerControl_GetBatchPeriod_Response`
`err`	`fuchsia.component/Error`

WorkSchedulerControl_SetBatchPeriod_Result

Name	Type	Description
`response`	`WorkSchedulerControl_SetBatchPeriod_Response`
`err`	`fuchsia.component/Error`

WorkScheduler_CancelWork_Result

Name	Type	Description
`response`	`WorkScheduler_CancelWork_Response`
`err`	`fuchsia.component/Error`

WorkScheduler_ScheduleWork_Result

Name	Type	Description
`response`	`WorkScheduler_ScheduleWork_Response`
`err`	`fuchsia.component/Error`

Worker_DoWork_Result