f10n/sdk/fidl/fuchsia.component.runner/README.md - reference-docs - Git at Google

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 [TOC]
 # fuchsia.component.runner

 <div class="fidl-version-div"><span class="fidl-attribute fidl-version">Added: 7</span></div>


 ## **PROTOCOLS**

 ## ComponentController {#ComponentController}
 *Defined in [fuchsia.component.runner/component_runner.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.component.runner/component_runner.fidl;l=183)*
 <p>A protocol for binding and controlling the lifetime of a component instance
 started using <code>ComponentRunner.Start()</code>. The component manager is the
 intended direct client of this protocol.</p>
 <p>When the controlled component instance terminates or becomes inaccessible
 for any reason, the server closes the connection with an epitaph.</p>
 <p>LIFECYCLE</p>
 <p>A component may exist in one of two states: <code>Started</code>, or <code>Stopped</code>. The
 component is <code>Started</code> from the time <code>ComponentRunner.Start()</code> is called
 until the ComponentRunner closes the ComponentController handle. The
 component then transitions to <code>Stopped</code>.</p>
 <p>Component manager uses ComponentController to terminate a component in two
 steps:</p>
 <ol>
 <li>Component manager calls <code>Stop()</code> to indicate that the ComponentRunner
 should stop a component's execution and close this connection with an
 epitaph.</li>
 <li>If after some time the ComponentController is not closed, component
 manager calls <code>Kill()</code> to indicate that the ComponentRunner must halt a
 component's execution immediately, and then close this connection with
 an epitaph. The component manager may wait some period of time after
 calling <code>Kill()</code> before closing the ComponentController channel, but
 makes no guarantees it will wait or for how long.</li>
 </ol>
 <p>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 <code>Kill()</code> without first having called <code>Stop()</code>.</p>
 <p>EPITAPH</p>
 <p>This protocol sends a FIDL epitaph to indicate that the component instance
 has been terminated. The component runner is expected to clean up all
 resources attributed to the component before closing the connection.</p>
 <p>The following epitaphs may be sent by the server on error:</p>
 <ul>
 <li><code>ZX_OK</code>: The component exited successfully, typically because the
 component was asked to stop or it decided independently to exit.</li>
 <li><code>INVALID_ARGUMENTS</code>:
 <ul>
 <li><code>start_info.resolved_url</code> is not supported by this
 runner;</li>
 <li><code>start_info</code> contains missing or invalid arguments.</li>
 </ul>
 </li>
 <li><code>INSTANCE_CANNOT_START</code>: 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.</li>
 <li><code>RESOURCE_UNAVAILABLE</code>: The component could not be launched due to
 lack of resources.</li>
 <li><code>INTERNAL</code>: An unexpected internal runner error was encountered.</li>
 <li><code>INSTANCE_DIED</code>: The component instance was started but
 subsequently terminated with an error.</li>
 <li>Other status codes (e.g. <code>ZX_ERR_PEER_CLOSED</code>) 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.</li>
 </ul>


 ### Kill {#ComponentController.Kill}

 <p>Stop this component instance immediately.</p>
 <p>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.</p>
 <p>In some cases Kill() may be issued before Stop(), but that is not
 guaranteed.</p>


 #### Request {#ComponentController.Kill_Request}

 &lt;EMPTY&gt;


 ### OnPublishDiagnostics {#ComponentController.OnPublishDiagnostics}

 <p>Event for runners to publish diagnostics to the platform.</p>
 <p>This event signals to the platform that the runner for this
 component is publishing diagnostics about the runtime of the
 component. The component manager may optionally expose this data
 to clients.</p>


 #### Response {#ComponentController.OnPublishDiagnostics_Response}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>payload</code></td>
             <td>
                 <code><a class='link' href='../fuchsia.diagnostics.types/'>fuchsia.diagnostics.types</a>/<a class='link' href='../fuchsia.diagnostics.types/#ComponentDiagnostics'>ComponentDiagnostics</a></code>
             </td>
         </tr>
 </table>

 ### Stop {#ComponentController.Stop}

 <p>Request to stop the component instance.</p>
 <p>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.</p>


 #### Request {#ComponentController.Stop_Request}

 &lt;EMPTY&gt;


 ## ComponentRunner {#ComponentRunner}
 *Defined in [fuchsia.component.runner/component_runner.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.component.runner/component_runner.fidl;l=27)*
 <p>A protocol used for running components.</p>
 <p>This protocol is implemented by components which provide a runtime
 environment for other components.</p>
 <p>Note: The component manager is the only intended direct client of this
 interface.</p>


 ### Start {#ComponentRunner.Start}

 <p>Start running a component instance described by <code>start_info</code>.</p>
 <p>Component manager binds and uses <code>controller</code> to control the
 lifetime of the newly started component instance.</p>
 <p>Errors are delivered as epitaphs over the <code>ComponentController</code>
 protocol. In the event of an error, the runner must ensure that
 resources are cleaned up.</p>
 <p>Errors:</p>


 #### Request {#ComponentRunner.Start_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>start_info</code></td>
             <td>
                 <code><a class='link' href='#ComponentStartInfo'>ComponentStartInfo</a></code>
             </td>
         </tr>
         <tr>
             <td><code>controller</code></td>
             <td>
                 <code>server_end&lt;<a class='link' href='#ComponentController'>ComponentController</a>&gt;</code>
             </td>
         </tr>
 </table>


 ## **TABLES**

 ### ComponentNamespaceEntry [resource](/fuchsia-src/reference/fidl/language/language.md#value-vs-resource){:.fidl-attribute} {#ComponentNamespaceEntry data-text="ComponentNamespaceEntry"}


 *Defined in [fuchsia.component.runner/component_runner.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.component.runner/component_runner.fidl;l=48)*
 <p>A single component namespace entry, which describes a namespace mount point
 (<code>path</code>) and the directory backing it (<code>directory</code>). This type is usually
 composed inside a vector.  See <code>ComponentStartInfo.ns</code> for more details.</p>

 <table>
     <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
         <tr id="ComponentNamespaceEntry.path">
 <td><h3 id="ComponentNamespaceEntry.path" class="add-link hide-from-toc">1</h3></td>
             <td><code>path</code></td>
             <td>
                 <code>string[1024]</code>
             </td>
             <td><p>The mount point for the directory, including a
 leading slash. For example: &quot;/pkg&quot;, &quot;/svc&quot;, or &quot;/config/data&quot;.</p>
 </td>
         </tr>
         <tr id="ComponentNamespaceEntry.directory">
 <td><h3 id="ComponentNamespaceEntry.directory" class="add-link hide-from-toc">2</h3></td>
             <td><code>directory</code></td>
             <td>
                 <code><a class='link' href='../fuchsia.io/'>fuchsia.io</a>/<a class='link' href='../fuchsia.io/#Directory'>Directory</a></code>
             </td>
             <td><p>The directory mounted at the above <code>path</code>.</p>
 </td>
         </tr>
 </table>

 ### ComponentStartInfo [resource](/fuchsia-src/reference/fidl/language/language.md#value-vs-resource){:.fidl-attribute} {#ComponentStartInfo data-text="ComponentStartInfo"}


 *Defined in [fuchsia.component.runner/component_runner.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.component.runner/component_runner.fidl;l=58)*
 <p>Parameters for starting a new component instance.</p>

 <table>
     <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
         <tr id="ComponentStartInfo.resolved_url">
 <td><h3 id="ComponentStartInfo.resolved_url" class="add-link hide-from-toc">1</h3></td>
             <td><code>resolved_url</code></td>
             <td>
                 <code><a class='link' href='../fuchsia.url/'>fuchsia.url</a>/<a class='link' href='../fuchsia.url/#Url'>Url</a></code>
             </td>
             <td><p>The resolved URL of the component.</p>
 <p>This is the canonical URL obtained by the component resolver after
 following redirects and resolving relative paths.</p>
 </td>
         </tr>
         <tr id="ComponentStartInfo.program">
 <td><h3 id="ComponentStartInfo.program" class="add-link hide-from-toc">2</h3></td>
             <td><code>program</code></td>
             <td>
                 <code><a class='link' href='../fuchsia.data/'>fuchsia.data</a>/<a class='link' href='../fuchsia.data/#Dictionary'>Dictionary</a></code>
             </td>
             <td><p>The component's program declaration.
 This information originates from <code>ComponentDecl.program</code>.</p>
 </td>
         </tr>
         <tr id="ComponentStartInfo.ns">
 <td><h3 id="ComponentStartInfo.ns" class="add-link hide-from-toc">3</h3></td>
             <td><code>ns</code></td>
             <td>
                 <code>vector&lt;<a class='link' href='#ComponentNamespaceEntry'>ComponentNamespaceEntry</a>&gt;[32]</code>
             </td>
             <td><p>The namespace to provide to the component instance.</p>
 <p>A namespace specifies the set of directories that a component instance
 receives at start-up. Through the namespace directories, a component
 may access capabilities available to it. The contents of the namespace
 are mainly determined by the component's <code>use</code> declarations but may
 also contain additional capabilities automatically provided by the
 framework.</p>
 <p>By convention, a component's namespace typically contains some or all
 of the following directories:</p>
 <ul>
 <li>&quot;/svc&quot;: A directory containing services that the component requested
 to use via its &quot;import&quot; declarations.</li>
 <li>&quot;/pkg&quot;: A directory containing the component's package, including its
 binaries, libraries, and other assets.</li>
 </ul>
 <p>The mount points specified in each entry must be unique and
 non-overlapping. For example, [{&quot;/foo&quot;, ..}, {&quot;/foo/bar&quot;, ..}] is
 invalid.</p>
 </td>
         </tr>
         <tr id="ComponentStartInfo.outgoing_dir">
 <td><h3 id="ComponentStartInfo.outgoing_dir" class="add-link hide-from-toc">4</h3></td>
             <td><code>outgoing_dir</code></td>
             <td>
                 <code>server_end&lt;<a class='link' href='../fuchsia.io/'>fuchsia.io</a>/<a class='link' href='../fuchsia.io/#Directory'>Directory</a>&gt;</code>
             </td>
             <td><p>The directory this component serves.</p>
 </td>
         </tr>
         <tr id="ComponentStartInfo.runtime_dir">
 <td><h3 id="ComponentStartInfo.runtime_dir" class="add-link hide-from-toc">5</h3></td>
             <td><code>runtime_dir</code></td>
             <td>
                 <code>server_end&lt;<a class='link' href='../fuchsia.io/'>fuchsia.io</a>/<a class='link' href='../fuchsia.io/#Directory'>Directory</a>&gt;</code>
             </td>
             <td><p>The directory served by the runner to present runtime information about
 the component. The runner must either serve it, or drop it to avoid
 blocking any consumers indefinitely.</p>
 </td>
         </tr>
         <tr id="ComponentStartInfo.numbered_handles">
 <td><h3 id="ComponentStartInfo.numbered_handles" class="add-link hide-from-toc">6</h3></td>
             <td><code>numbered_handles</code></td>
             <td>
                 <code>vector&lt;<a class='link' href='../fuchsia.process/'>fuchsia.process</a>/<a class='link' href='../fuchsia.process/#HandleInfo'>HandleInfo</a>&gt;[128]</code>
             </td>
             <td><p>The numbered handles that were passed to the component.</p>
 <p>If the component does not support numbered handles, the runner is expected
 to close the handles.</p>
 </td>
         </tr>
         <tr id="ComponentStartInfo.encoded_config">
 <td><h3 id="ComponentStartInfo.encoded_config" class="add-link hide-from-toc">7</h3></td>
             <td><code>encoded_config</code></td>
             <td>
                 <code><a class='link' href='../fuchsia.mem/'>fuchsia.mem</a>/<a class='link' href='../fuchsia.mem/#Data'>Data</a></code>
             </td>
             <td><p>Binary representation of the component's configuration.</p>
 <h1>Layout</h1>
 <p>The first 2 bytes of the data should be interpreted as an unsigned 16-bit
 little-endian integer which denotes the number of bytes following it that
 contain the configuration checksum. After the checksum, all the remaining
 bytes are a persistent FIDL message of a top-level struct. The struct's
 fields match the configuration fields of the component's compiled manifest
 in the same order.</p>
 </td>
         </tr>
         <tr id="ComponentStartInfo.break_on_start">
 <td><h3 id="ComponentStartInfo.break_on_start" class="add-link hide-from-toc">8</h3></td>
             <td><code>break_on_start</code></td>
             <td>
                 <code>handle&lt;eventpair&gt;</code>
             </td>
             <td><p>An eventpair that debuggers can use to defer the launch of the component.</p>
 <p>For example, ELF runners hold off from creating processes in the component
 until ZX_EVENTPAIR_PEER_CLOSED is signaled on this eventpair. They also
 ensure that runtime_dir is served before waiting on this eventpair.
 ELF debuggers can query the runtime_dir to decide whether to attach before
 they drop the other side of the eventpair, which is sent in the payload of
 the DebugStarted event in fuchsia.sys2.events.</p>
 </td>
         </tr>
 </table>


 ## **CONSTANTS**

 <table>
     <tr><th>Name</th><th>Value</th><th>Type</th><th>Description</th></tr>
         <tr id="MAX_HANDLE_COUNT">
             <td><a href="https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.component.runner/component_runner.fidl;l=17">MAX_HANDLE_COUNT</a></td>
                 <td>
                     <code>128</code>
                 </td>
                 <td><code>uint32</code></td>
             <td></td>
         </tr>
         <tr id="MAX_NAMESPACE_COUNT">
             <td><a href="https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.component.runner/component_runner.fidl;l=16">MAX_NAMESPACE_COUNT</a></td>
                 <td>
                     <code>32</code>
                 </td>
                 <td><code>uint32</code></td>
             <td></td>
         </tr>
 </table>
	<link rel="stylesheet" href="../style.css" />

	[TOC]
	# fuchsia.component.runner

	<div class="fidl-version-div"><span class="fidl-attribute fidl-version">Added: 7</span></div>


	## PROTOCOLS

	## ComponentController {#ComponentController}
	Defined in [fuchsia.component.runner/component_runner.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.component.runner/component_runner.fidl;l=183)
	<p>A protocol for binding and controlling the lifetime of a component instance
	started using <code>ComponentRunner.Start()</code>. The component manager is the
	intended direct client of this protocol.</p>
	<p>When the controlled component instance terminates or becomes inaccessible
	for any reason, the server closes the connection with an epitaph.</p>
	<p>LIFECYCLE</p>
	<p>A component may exist in one of two states: <code>Started</code>, or <code>Stopped</code>. The
	component is <code>Started</code> from the time <code>ComponentRunner.Start()</code> is called
	until the ComponentRunner closes the ComponentController handle. The
	component then transitions to <code>Stopped</code>.</p>
	<p>Component manager uses ComponentController to terminate a component in two
	steps:</p>
	<ol>
	<li>Component manager calls <code>Stop()</code> to indicate that the ComponentRunner
	should stop a component's execution and close this connection with an
	epitaph.</li>
	<li>If after some time the ComponentController is not closed, component
	manager calls <code>Kill()</code> to indicate that the ComponentRunner must halt a
	component's execution immediately, and then close this connection with
	an epitaph. The component manager may wait some period of time after
	calling <code>Kill()</code> before closing the ComponentController channel, but
	makes no guarantees it will wait or for how long.</li>
	</ol>
	<p>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 <code>Kill()</code> without first having called <code>Stop()</code>.</p>
	<p>EPITAPH</p>
	<p>This protocol sends a FIDL epitaph to indicate that the component instance
	has been terminated. The component runner is expected to clean up all
	resources attributed to the component before closing the connection.</p>
	<p>The following epitaphs may be sent by the server on error:</p>
	<ul>
	<li><code>ZX_OK</code>: The component exited successfully, typically because the
	component was asked to stop or it decided independently to exit.</li>
	<li><code>INVALID_ARGUMENTS</code>:
	<ul>
	<li><code>start_info.resolved_url</code> is not supported by this
	runner;</li>
	<li><code>start_info</code> contains missing or invalid arguments.</li>
	</ul>
	</li>
	<li><code>INSTANCE_CANNOT_START</code>: 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.</li>
	<li><code>RESOURCE_UNAVAILABLE</code>: The component could not be launched due to
	lack of resources.</li>
	<li><code>INTERNAL</code>: An unexpected internal runner error was encountered.</li>
	<li><code>INSTANCE_DIED</code>: The component instance was started but
	subsequently terminated with an error.</li>
	<li>Other status codes (e.g. <code>ZX_ERR_PEER_CLOSED</code>) 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.</li>
	</ul>


	### Kill {#ComponentController.Kill}

	<p>Stop this component instance immediately.</p>
	<p>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.</p>
	<p>In some cases Kill() may be issued before Stop(), but that is not
	guaranteed.</p>



	#### Request {#ComponentController.Kill_Request}

	<EMPTY>


	### OnPublishDiagnostics {#ComponentController.OnPublishDiagnostics}

	<p>Event for runners to publish diagnostics to the platform.</p>
	<p>This event signals to the platform that the runner for this
	component is publishing diagnostics about the runtime of the
	component. The component manager may optionally expose this data
	to clients.</p>




	#### Response {#ComponentController.OnPublishDiagnostics_Response}

	<table>
	<tr><th>Name</th><th>Type</th></tr>
	<tr>
	<td><code>payload</code></td>
	<td>
	<code><a class='link' href='../fuchsia.diagnostics.types/'>fuchsia.diagnostics.types</a>/<a class='link' href='../fuchsia.diagnostics.types/#ComponentDiagnostics'>ComponentDiagnostics</a></code>
	</td>
	</tr>
	</table>

	### Stop {#ComponentController.Stop}

	<p>Request to stop the component instance.</p>
	<p>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.</p>



	#### Request {#ComponentController.Stop_Request}

	<EMPTY>


	## ComponentRunner {#ComponentRunner}
	Defined in [fuchsia.component.runner/component_runner.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.component.runner/component_runner.fidl;l=27)
	<p>A protocol used for running components.</p>
	<p>This protocol is implemented by components which provide a runtime
	environment for other components.</p>
	<p>Note: The component manager is the only intended direct client of this
	interface.</p>


	### Start {#ComponentRunner.Start}

	<p>Start running a component instance described by <code>start_info</code>.</p>
	<p>Component manager binds and uses <code>controller</code> to control the
	lifetime of the newly started component instance.</p>
	<p>Errors are delivered as epitaphs over the <code>ComponentController</code>
	protocol. In the event of an error, the runner must ensure that
	resources are cleaned up.</p>
	<p>Errors:</p>



	#### Request {#ComponentRunner.Start_Request}

	<table>
	<tr><th>Name</th><th>Type</th></tr>
	<tr>
	<td><code>start_info</code></td>
	<td>
	<code><a class='link' href='#ComponentStartInfo'>ComponentStartInfo</a></code>
	</td>
	</tr>
	<tr>
	<td><code>controller</code></td>
	<td>
	<code>server_end<<a class='link' href='#ComponentController'>ComponentController</a>></code>
	</td>
	</tr>
	</table>





	## TABLES

	### ComponentNamespaceEntry [resource](/fuchsia-src/reference/fidl/language/language.md#value-vs-resource){:.fidl-attribute} {#ComponentNamespaceEntry data-text="ComponentNamespaceEntry"}


	Defined in [fuchsia.component.runner/component_runner.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.component.runner/component_runner.fidl;l=48)
	<p>A single component namespace entry, which describes a namespace mount point
	(<code>path</code>) and the directory backing it (<code>directory</code>). This type is usually
	composed inside a vector. See <code>ComponentStartInfo.ns</code> for more details.</p>

	<table>
	<tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
	<tr id="ComponentNamespaceEntry.path">
	<td><h3 id="ComponentNamespaceEntry.path" class="add-link hide-from-toc">1</h3></td>
	<td><code>path</code></td>
	<td>
	<code>string[1024]</code>
	</td>
	<td><p>The mount point for the directory, including a
	leading slash. For example: "/pkg", "/svc", or "/config/data".</p>
	</td>
	</tr>
	<tr id="ComponentNamespaceEntry.directory">
	<td><h3 id="ComponentNamespaceEntry.directory" class="add-link hide-from-toc">2</h3></td>
	<td><code>directory</code></td>
	<td>
	<code><a class='link' href='../fuchsia.io/'>fuchsia.io</a>/<a class='link' href='../fuchsia.io/#Directory'>Directory</a></code>
	</td>
	<td><p>The directory mounted at the above <code>path</code>.</p>
	</td>
	</tr>
	</table>

	### ComponentStartInfo [resource](/fuchsia-src/reference/fidl/language/language.md#value-vs-resource){:.fidl-attribute} {#ComponentStartInfo data-text="ComponentStartInfo"}


	Defined in [fuchsia.component.runner/component_runner.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.component.runner/component_runner.fidl;l=58)
	<p>Parameters for starting a new component instance.</p>

	<table>
	<tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
	<tr id="ComponentStartInfo.resolved_url">
	<td><h3 id="ComponentStartInfo.resolved_url" class="add-link hide-from-toc">1</h3></td>
	<td><code>resolved_url</code></td>
	<td>
	<code><a class='link' href='../fuchsia.url/'>fuchsia.url</a>/<a class='link' href='../fuchsia.url/#Url'>Url</a></code>
	</td>
	<td><p>The resolved URL of the component.</p>
	<p>This is the canonical URL obtained by the component resolver after
	following redirects and resolving relative paths.</p>
	</td>
	</tr>
	<tr id="ComponentStartInfo.program">
	<td><h3 id="ComponentStartInfo.program" class="add-link hide-from-toc">2</h3></td>
	<td><code>program</code></td>
	<td>
	<code><a class='link' href='../fuchsia.data/'>fuchsia.data</a>/<a class='link' href='../fuchsia.data/#Dictionary'>Dictionary</a></code>
	</td>
	<td><p>The component's program declaration.
	This information originates from <code>ComponentDecl.program</code>.</p>
	</td>
	</tr>
	<tr id="ComponentStartInfo.ns">
	<td><h3 id="ComponentStartInfo.ns" class="add-link hide-from-toc">3</h3></td>
	<td><code>ns</code></td>
	<td>
	<code>vector<<a class='link' href='#ComponentNamespaceEntry'>ComponentNamespaceEntry</a>>[32]</code>
	</td>
	<td><p>The namespace to provide to the component instance.</p>
	<p>A namespace specifies the set of directories that a component instance
	receives at start-up. Through the namespace directories, a component
	may access capabilities available to it. The contents of the namespace
	are mainly determined by the component's <code>use</code> declarations but may
	also contain additional capabilities automatically provided by the
	framework.</p>
	<p>By convention, a component's namespace typically contains some or all
	of the following directories:</p>
	<ul>
	<li>"/svc": A directory containing services that the component requested
	to use via its "import" declarations.</li>
	<li>"/pkg": A directory containing the component's package, including its
	binaries, libraries, and other assets.</li>
	</ul>
	<p>The mount points specified in each entry must be unique and
	non-overlapping. For example, [{"/foo", ..}, {"/foo/bar", ..}] is
	invalid.</p>
	</td>
	</tr>
	<tr id="ComponentStartInfo.outgoing_dir">
	<td><h3 id="ComponentStartInfo.outgoing_dir" class="add-link hide-from-toc">4</h3></td>
	<td><code>outgoing_dir</code></td>
	<td>
	<code>server_end<<a class='link' href='../fuchsia.io/'>fuchsia.io</a>/<a class='link' href='../fuchsia.io/#Directory'>Directory</a>></code>
	</td>
	<td><p>The directory this component serves.</p>
	</td>
	</tr>
	<tr id="ComponentStartInfo.runtime_dir">
	<td><h3 id="ComponentStartInfo.runtime_dir" class="add-link hide-from-toc">5</h3></td>
	<td><code>runtime_dir</code></td>
	<td>
	<code>server_end<<a class='link' href='../fuchsia.io/'>fuchsia.io</a>/<a class='link' href='../fuchsia.io/#Directory'>Directory</a>></code>
	</td>
	<td><p>The directory served by the runner to present runtime information about
	the component. The runner must either serve it, or drop it to avoid
	blocking any consumers indefinitely.</p>
	</td>
	</tr>
	<tr id="ComponentStartInfo.numbered_handles">
	<td><h3 id="ComponentStartInfo.numbered_handles" class="add-link hide-from-toc">6</h3></td>
	<td><code>numbered_handles</code></td>
	<td>
	<code>vector<<a class='link' href='../fuchsia.process/'>fuchsia.process</a>/<a class='link' href='../fuchsia.process/#HandleInfo'>HandleInfo</a>>[128]</code>
	</td>
	<td><p>The numbered handles that were passed to the component.</p>
	<p>If the component does not support numbered handles, the runner is expected
	to close the handles.</p>
	</td>
	</tr>
	<tr id="ComponentStartInfo.encoded_config">
	<td><h3 id="ComponentStartInfo.encoded_config" class="add-link hide-from-toc">7</h3></td>
	<td><code>encoded_config</code></td>
	<td>
	<code><a class='link' href='../fuchsia.mem/'>fuchsia.mem</a>/<a class='link' href='../fuchsia.mem/#Data'>Data</a></code>
	</td>
	<td><p>Binary representation of the component's configuration.</p>
	<h1>Layout</h1>
	<p>The first 2 bytes of the data should be interpreted as an unsigned 16-bit
	little-endian integer which denotes the number of bytes following it that
	contain the configuration checksum. After the checksum, all the remaining
	bytes are a persistent FIDL message of a top-level struct. The struct's
	fields match the configuration fields of the component's compiled manifest
	in the same order.</p>
	</td>
	</tr>
	<tr id="ComponentStartInfo.break_on_start">
	<td><h3 id="ComponentStartInfo.break_on_start" class="add-link hide-from-toc">8</h3></td>
	<td><code>break_on_start</code></td>
	<td>
	<code>handle<eventpair></code>
	</td>
	<td><p>An eventpair that debuggers can use to defer the launch of the component.</p>
	<p>For example, ELF runners hold off from creating processes in the component
	until ZX_EVENTPAIR_PEER_CLOSED is signaled on this eventpair. They also
	ensure that runtime_dir is served before waiting on this eventpair.
	ELF debuggers can query the runtime_dir to decide whether to attach before
	they drop the other side of the eventpair, which is sent in the payload of
	the DebugStarted event in fuchsia.sys2.events.</p>
	</td>
	</tr>
	</table>




	## CONSTANTS

	<table>
	<tr><th>Name</th><th>Value</th><th>Type</th><th>Description</th></tr>
	<tr id="MAX_HANDLE_COUNT">
	<td><a href="https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.component.runner/component_runner.fidl;l=17">MAX_HANDLE_COUNT</a></td>
	<td>
	<code>128</code>
	</td>
	<td><code>uint32</code></td>
	<td></td>
	</tr>
	<tr id="MAX_NAMESPACE_COUNT">
	<td><a href="https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.component.runner/component_runner.fidl;l=16">MAX_NAMESPACE_COUNT</a></td>
	<td>
	<code>32</code>
	</td>
	<td><code>uint32</code></td>
	<td></td>
	</tr>
	</table>