pub enum ComponentControllerRequest {
Stop {
control_handle: ComponentControllerControlHandle,
},
Kill {
control_handle: ComponentControllerControlHandle,
},
_UnknownMethod {
ordinal: u64,
control_handle: ComponentControllerControlHandle,
method_type: MethodType,
},
}
Expand description
A protocol for binding and controlling the lifetime of a component instance
started using ComponentRunner.Start()
. The component manager is the
intended direct client of this protocol.
When the controlled component instance terminates or becomes inaccessible for any reason, the server closes the connection with an epitaph.
§Lifecycle
A component may exist in one of two states: Started
, or Stopped
. The
component is Started
from the time ComponentRunner.Start()
is called
until the ComponentRunner closes the ComponentController handle. The
component then transitions to Stopped
.
Component manager uses ComponentController to terminate a component in two steps:
- Component manager calls
Stop()
to indicate that the ComponentRunner should stop a component’s execution and send theOnStop
event. - If after some time the ComponentController is not closed, component
manager calls
Kill()
to indicate that the ComponentRunner must halt a component’s execution immediately, and then send theOnStop
event. The component manager may wait some period of time after callingKill()
before sendingOnStop
, but makes no guarantees it will wait or for how long.
Component manager first waits for the ComponentController to close, and
then tears down the namespace it hosts for the stopped component. Component
manager may call Kill()
without first having called Stop()
.
Before stopping, a component can optionally use OnEscrow
to store some
state in the framework, to receive those state again the next time it is
started.
When the component stops, the runner should send an OnStop
event
instead of just closing the channel, to report the component’s termination status
(see below) and (optionally) an exit code. Once the runner has sent OnStop
it is free to close [ComponentRunner]; the component framework will close
its end of the channel when it receives this event.
§Legacy
Instead of sending OnStop
, it is also legal for a runner to close the channel
with with an epitaph equal to the termination status, but this is a legacy method
for backward compatibility that’s no longer recommended.
§Termination status
The termination status indicates the component’s final disposition in the eyes of the runner.
Note that termination status is not synonymous with a component’s exit code. A component’s exit code, which is optional for a runner to report, is an integer that represents the program’s own return code. For example, for ELF components, it is the value returned by main(). The termination status is the runner’s status code for the component’s termination, which may capture failure modes that occur in the context of the runner itself rather than the program.
The following termination statuses may be sent by the server on error:
ZX_OK
: The component exited successfully, typically because the component was asked to stop or it decided independently to exit.INVALID_ARGUMENTS
:start_info.resolved_url
is not supported by this runner;start_info
contains missing or invalid arguments.
INSTANCE_CANNOT_START
: The runner could not start the component. For example, a critical part of the program could not be found or loaded, or the referenced binary was invalid for this runner.RESOURCE_UNAVAILABLE
: The component could not be launched due to lack of resources.INTERNAL
: An unexpected internal runner error was encountered.INSTANCE_DIED
: The component instance was started but subsequently terminated with an error.- Other status codes (e.g.
ZX_ERR_PEER_CLOSED
) may indicate a failure of the component runner itself. The component manager may respond to such failures by terminating the component runner’s job to ensure system stability.
Variants§
Stop
Request to stop the component instance.
After stopping the component instance, the server should close this connection with an epitaph. After the connection closes, component manager considers this component instance to be Stopped and the component’s namespace will be torn down.
Fields
control_handle: ComponentControllerControlHandle
Kill
Stop this component instance immediately.
The ComponentRunner must immediately kill the component instance, and then close this connection with an epitaph. After the connection closes, component manager considers this component instance to be Stopped and the component’s namespace will be torn down.
In some cases Kill() may be issued before Stop(), but that is not guaranteed.
Fields
control_handle: ComponentControllerControlHandle
_UnknownMethod
An interaction was received which does not match any known method.
Fields
This variant is marked as non-exhaustive
control_handle: ComponentControllerControlHandle
method_type: MethodType
Implementations§
Source§impl ComponentControllerRequest
impl ComponentControllerRequest
pub fn into_stop(self) -> Option<ComponentControllerControlHandle>
pub fn into_kill(self) -> Option<ComponentControllerControlHandle>
Sourcepub fn method_name(&self) -> &'static str
pub fn method_name(&self) -> &'static str
Name of the method defined in FIDL