fuchsia.component.decl

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.

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.

Name used in the source instance.

Name used in the target instance.

STATIC_ONLY

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

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.

REQUIRED

The capability must be available. Failure to route the capability is an error.

OPTIONAL

Inside a use declaration: the component can function if it fails to obtain the capability.

Inside an offer/expose declaration: the capability may not be available in some system configurations. As a corollary, the target component must not have a required dependency on the capability.

SAME_AS_TARGET

If the target of the corresponding offer or expose declaration requires the capability, then the behavior is equivalent to required. If the target has an optional dependency on the capability, then the behavior is equivalent to optional. This is useful for container components that would like to change their routing availability based on ones inside.

This value is not allowed inside a use declaration.

TRANSITIONAL

The source may omit the route completely without even having to route from void.

TRANSITIONAL is used for soft transitions that introduce new capabilities.

BOOL

UINT8

UINT16

UINT32

UINT64

INT8

INT16

INT32

INT64

STRING

VECTOR

STRONG

A strong dependency which may be required by components that use it.

WEAK

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

A weak dependency specifically used to mark cyclic dependencies from migrated v1 components.

TRANSIENT

An instance exists until either its parent instance is stopped or it is explicitly destroyed.

SINGLE_RUN

An instance is started upon creation and is immediately destroyed when it stops.

NONE

The environment has no initial set of properties.

REALM

The environment's initial set of properties are inherited from its realm. Inherited properties include any fields defined in EnvironmentDecl.

NONE

No action, the default

REBOOT

Trigger a graceful system reboot if the component terminates for any reason. This is a specialized feature gated by Component Framework security policy.

LAZY

Start component instance only when another instance binds to it.

EAGER

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.

STATIC_INSTANCE_ID

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

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.

1

(Required) 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

(Required) The child component's URL.

Must be non-empty and a well-formed URL.

3

(Required) The startup mode for the component instance.

Must be set.

4

(Optional) The environment assigned to this child.

May be unset, in which case the child will inherit the parent component's environment. If set, the name must reference an environment defined in the ComponentDecl and it must contain only the following characters: [a-z0-9-_.].

5

(Optional, defaults to NONE) The action to take if this component instance terminates unexpectedly.

6

Configuration overrides to apply to the child's base configuration.

For a configuration field to be overridden it must be marked as mutable by parent.

Parents must pass ConfigOverride values which match the child's declared schema types exactly.

1

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

2

(Required) The durability of instances in the collection.

3

(Optional) The environment assigned to child instances in this collection.

May be unset, in which case children in this collection will inherit the parent component's environment. If set, the name must reference an environment defined in the ComponentDecl and it must contain only the following characters: [a-z0-9-_.].

4

(Optional, defaults to STATIC_ONLY) The kinds of offers that can target the child instances in this collection.

Only components using the dynamic_offers restricted feature may set this field.

5

(Optional, defaults to false) Whether child instances in this collection can have names longer than the default length limit of 100.

Only components using the allow_long_names restricted feature may set this field.

6

(Optional) Whether the data in isolated storage used by dynamic child instances and their descendants will persist after the instances are destroyed. New dynamic instances inherit the previous instances' data stores.

This setting can be overridden by a lower-level collection that is a descendant of a collection that enables/disables this setting.

This setting applies to all storage capabilities consumed by the collection components and their descendants.

The default is the value inherited from an ancestral collection if set, otherwise false.

1

(Optional) Information about the program to run when the component is executed. Omitted for non-executable components.

2

(Optional) 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

(Optional) 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

(Optional) 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

(Optional) List of capabilities defined by the component.

6

(Optional) The component's statically instantiated children. The children must have unique names.

7

(Optional) The component's collections. The collections must have unique names.

8

(Optional) List of environments created by this component. Environments are assigned to children and control aspects of a child component's runtime.

9

(Optional) Additional metadata about the component.

10

(Optional) The schema of the component's configuration interface.

1

(Required) The identifier for this config field. This key will be used to match overrides.

2

(Required) The type of config values. Config values are verified against this layout at build time and run time.

3

Allowed sources for runtime overrides of this field's value.

1

2

1

(Required) Ordered fields of the component's configuration interface.

2

(Required) Checksum over the config declaration.

3

(Required) Strategy used to resolve config values.

1

1

The concrete values for the component's configuration.

2

A SHA-256 checksum of the configuration schema. Must match the checksum in the component manifest and config parser library used to resolve the final configuration.

1

(Required) The provider of the capability relative to the component itself. Must be parent, self, or child.

2

(Required) Name identifying the protocol being offered.

3

(Required) The name by which the capability is being offered.

1

(Required) The name of this directory.

2

(Required) The path to the directory in the component's outgoing directory.

3

(Required) The maximum rights that can be set by a component using this directory.

1

(Required) The name of this environment.

2

(Required) Specifies how the initial state of this environment is constructed.

3

(Optional) 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

(Optional) 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

(Optional) Expose capabilities 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

(Optional) The duration in milliseconds that the component will have to stop before it is killed. Required if this environment extends from NONE.

1

(Required) The name of this event stream.

Must be unique among built-in capabilities.

1

(Required) The event names to subscribe to.

1

(Required) The provider of the capability relative to the component itself. Must be self or child, or void. If set to void, then the target must expose, offer, or use the capability with OPTIONAL or TRANSITIONAL availability.

2

(Required) Name identifying the directory, by which it was presented to this component.

3

(Required) The destination to which the directory is exposed: either the component's realm or the framework.

4

(Required) The name by which the capability is being exposed.

5

(Optional) The maximum rights that can be set by a component using this directory. If unset, the rights are inherited from source.

6

(Optional) The subdirectory of this directory to expose instead of the root.

7

(Optional, defaults to REQUIRED) The availability of this capability. See Availability.

1

(Required) The provider of the capability relative to the component itself. Must be self or child, or void. If set to void, then the target must expose, offer, or use the capability with OPTIONAL or TRANSITIONAL availability.

2

(Required) Name identifying the protocol, by which it was presented to this component.

3

(Required) The destination to which the protocol is exposed: either the component's realm or the framework.

4

(Required) The name by which the capability is being exposed.

5

(Optional, defaults to REQUIRED) The availability of this capability. See Availability.

1

(Required) The provider of the capability relative to the component itself. Must be self or child.

2

(Required) The name of the resolver, by which it was presented to this component.

3

(Required) The destination to which the resolver is exposed

4

(Required) The name by which the capability is being exposed.

1

(Required) The provider of the capability relative to the component itself. Must be self or child.

2

(Required) The name of the runner, by which it was presented to this component.

3

(Required) The destination to which the runner is exposed: either the component's realm or the framework.

4

(Required) The name by which the capability is being exposed.

1

(Required) The provider of the capability relative to the component itself. Must be self or child, or void. If set to void, then the target must expose, offer, or use the capability with OPTIONAL or TRANSITIONAL availability.

2

(Required) Name identifying the service, by which it was presented to this component.

3

(Required) The destination to which the service is exposed: either the component's realm or the framework.

4

(Required) The name by which the capability is being exposed.

5

(Optional, defaults to REQUIRED) The availability of this capability. See Availability.

1

(Required) The provider of the capability relative to the component itself. Must be parent, self, child, framework, or void. If set to void, then the target must offer or use the capability with OPTIONAL or TRANSITIONAL availability.

2

(Required) Name identifying the directory being offered.

3

(Required) Reference to the target of the capability. Must be child or collection.

4

(Required) The name by which the capability is being offered.

5

(Optional) The maximum rights that can be set by a component using this directory. IF unset, the rights are inherited from source.

6

(Optional) The subdirectory of this directory to offer instead of the root. Optional.

7

(Required) The dependency type this offer represents. A component which receives a weak offer must support the offered capability being unavailable at any point.

8

(Optional, defaults to REQUIRED) The availability of this capability. If set to required, the target may use or offer the capability with either required or optional availability. If set to optional, the target must use or offer the capability with optional availability. The same_as_target value causes this offer's availability to match the availability set in the target.

1

(Required) The provider of the capability relative to the component itself. Must be parent, framework, child, or void. If set to void, then the target must offer or use the capability with OPTIONAL or TRANSITIONAL availability.

2

(Required) Name of the event being offered.

3

(Optional) When an event is offered from framework, the scope is required and allows one to define the child (or array of children) which the event is about. When the event is offered from parent, the scope can be used to downscope the event to a certain child scope, otherwise the event will carry the scope coming from the parent.

4

(Required) The destination to which the event stream is offered.

5

(Required) Name under which the event stream is being offered.

6

(Optional) Filter for the event stream. Only present for DirectoryReady events and CapabilityRequested events

7

(Optional, defaults to REQUIRED) The availability of this capability. If set to required, the target may use or offer the capability with either required or optional availability. If set to optional, the target must use or offer the capability with optional availability. The same_as_target value causes this offer's availability to match the availability set in the target.

1

(Required) The provider of the capability relative to the component itself. Must be parent, self, child, framework, or void. If set to void, then the target must offer or use the capability with OPTIONAL or TRANSITIONAL availability.

2

(Required) Name identifying the protocol being offered.

3

(Required) Reference to the target. Must be child or collection.

4

(Required) The name by which the capability is being offered.

5

(Required) The dependency type this offer represents. A component which receives a weak offer must support the offered capability being unavailable at any point.

6

(Optional, defaults to REQUIRED) The availability of this capability. If set to required, the target may use or offer the capability with either required or optional availability. If set to optional, the target must use or offer the capability with optional availability. The same_as_target value causes this offer's availability to match the availability set in the target.

1

(Required) The provider of the capability relative to the component itself. Must be parent, self, or child.

2

(Required) Name of the resolver being offered.

3

(Required) Reference to the target of the capability. Must be child or collection.

4

(Required) Name under which the capability is being offered.

1

(Required) The provider of the capability relative to the component itself. Must be parent, self, or child.

2

(Required) Name of the runner being offered.

3

(Required) Reference to the target of the capability. Must be child or collection.

4

(Required) Name under which the capability is being offered.

1

(Required) The provider of the capability relative to the component itself. Must be parent, self, child, or void. If set to void, then the target must offer or use the capability with OPTIONAL or TRANSITIONAL availability.

2

(Required) Name identifying the service being offered.

3

(Required) Reference to the target. Must be child or collection.

4

(Required) The name under which the capability is being offered.

5

(Optional) The list of allow listed instances to be offered. Instances of the service not in this list will not be accessible by the target component. If this is not set that means all instances from the source service are offered.

6

(Optional) List of renamed service instances.

7

(Optional, defaults to REQUIRED) The availability of this capability. If set to required, the target may use or offer the capability with either required or optional availability. If set to optional, the target must use or offer the capability with optional availability. The same_as_target value causes this offer's availability to match the availability set in the target.

1

(Required) The name of the storage capability being offered

2

(Required) The provider of the capability relative to the component itself. Must be parent, storage, or void. If set to void, then the target must offer or use the capability with OPTIONAL or TRANSITIONAL availability.

3

(Required) Reference to the target of the capability. Must be child or collection.

4

(Required) The name the storage capability is being offered as

5

(Optional, defaults to REQUIRED) The availability of this capability. If set to required, the target may use or offer the capability with either required or optional availability. If set to optional, the target must use or offer the capability with optional availability. The same_as_target value causes this offer's availability to match the availability set in the target.

1

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

2

(Required) 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.

• The keys represent namespaced properties, delimited by ".".
• Properties may be nested in values, but only in the case of an object vector.

1

(Required) The name of this protocol.

2

(Required) The path to the protocol in the component's outgoing directory.

1

(Required) The name of this resolver.

Must be unique among resolvers declared in the same ComponentDecl.

2

(Required) The path to the resolver protocol in the component's outgoing directory

1

(Required) The name of the resolver.

2

(Required) The provider of the capability relative to the component itself. Must be parent, self, or child.

3

(Required) 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 ..

1

(Required) The name of this runner.

Must unique among runners declared in the same ComponentDecl.

2

(Required) The path to the runner protocol in the component's outgoing directory.

1

(Required) The name of the runner capability as it's exposed to, offered, or defined by this component.

2

(Required) The provider of the capability relative to the component itself. Must be parent, self, or child.

3

(Required) The name by which the runner is made available in this environment.

1

(Required) The name of this service.

2

(Required) The path to the service in the component's outgoing directory.

1

(Required) The name of this storage

2

(Required) The provider of the backing directory capability relative to the component itself. Must be parent, self, or child.

3

(Required) The name of the directory capability from source that backs the storage.

4

(Optional) The subdirectory of the source directory that will back the storage

5

(Required) This enum determines how to key a component's isolated storage directory. Each option corresponds to a different key'ing strategy.

1

(Required) The provider of the directory relative to the component itself. Must be parent, framework, or child. If the availability is set to optional, then this must be set to parent.

2

(Required) Name identifying the directory, by which it was presented to this component.

3

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

Must be an absolute path starting with /.

4

(Required) The rights required by the component to use this directory.

5

(Optional) The subdirectory of this directory to use instead of the root.

6

(Required) 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.

7

(Optional, defaults to REQUIRED) The availability of this capability. If set to required, the component is likely to malfunction if this capability is not provided. If set to optional, the component can handle the capability's absence.

1

(Required) The names of the event streams.

2

(Required) The provider of the event. Must be parent, framework, or child. If the availability is set to optional, then this must be set to parent.

3

(Optional) When an event is used from framework, the scope is required to specify the child (or array of children) which the event will be about. When the event is used from parent, the scope can be used to downscope the event to a certain child scope, otherwise the event will carry the scope coming from the parent.

4

(Required) The path where the capability should be installed in the component's namespace. Must be an absolute path starting with /.

5

(Optional, defaults to REQUIRED) The availability of this capability. If set to required, the component is likely to malfunction if this capability is not provided. If set to optional, the component can handle the capability's absence.

6

(Optional) Filter for the event stream. The structure of the filter depends on the event stream type. Only supported for the DirectoryReady and CapabilityRequested event types.

1

(Required) The provider of the protocol relative to the component itself. Must be parent, framework, debug, capability, or child. If the availability is set to optional, then this must be set to parent.

2

(Required) Name identifying the protocol, by which it was presented to this component.

3

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

Must be an absolute path starting with /.

4

(Required) 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.

5

(Optional, defaults to REQUIRED) The availability of this capability. If set to required, the component is likely to malfunction if this capability is not provided. If set to optional, the component can handle the capability's absence.

1

(Required) The provider of the service relative to the component itself. Must be parent or framework. If the availability is set to optional, then this must be set to parent.

2

(Required) Name identifying the service, by which it was presented to this component.

3

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

Must be an absolute path starting with /.

4

(Required) 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.

5

(Optional, defaults to REQUIRED) The availability of this capability. If set to required, the component is likely to malfunction if this capability is not provided. If set to optional, the component can handle the capability's absence.

1

(Required) Name identifying the storage, by which it was presented to this component. If the availability is set to optional, then this must be set to parent.

2

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

Must be an absolute path starting with /.

3

(Optional, defaults to REQUIRED) The availability of this capability. If set to required, the component is likely to malfunction if this capability is not provided. If set to optional, the component can handle the capability's absence.

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8

1

A SHA-256 hash produced over a component's config interface.

1

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7

8

9

10

1

2

1

(Required) The path within the component's package at which to find config value files.

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8

9

10

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PARENT

Allow parent components to provide overrides for the configuration field.

Config keys can only consist of these many bytes

The maximum number of EventSubscriptions in an EventStream.

The string identifier for a config field.