f11/sdk/fidl/fuchsia.session/README.md

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# fuchsia.session

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


## **PROTOCOLS**

## Launcher {#Launcher}
*Defined in [fuchsia.session/launcher.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.session/launcher.fidl;l=11)*
<p>A protocol used to launch sessions.</p>


### Launch {#Launcher.Launch}

<p>Launches the session detailed in <code>configuration</code>.</p>
<p>If a session is currently running, the component associated with the running
session will be destroyed.</p>
<ul>
<li><code>configuration</code> describes the session to launch.</li>
</ul>
<ul>
<li>error <code>LaunchError.INVALID_ARGS</code> if <code>configuration.session_url</code> is not set.</li>
<li>error <code>LaunchError.NOT_FOUND</code> if <code>configuration.session_url</code>
could not be resolved.</li>
<li>error <code>LaunchError.DESTROY_COMPONENT_FAILED</code> if an existing session component
could not be destroyed. The existing session remains running at this point.</li>
<li>error <code>LaunchError.CREATE_COMPONENT_FAILED</code> if the session component
could not be started. No session will be running at this point.</li>
</ul>



#### Request {#Launcher.Launch_Request}

<table>
    <tr><th>Name</th><th>Type</th></tr>
        <tr>
            <td><code>configuration</code></td>
            <td>
                <code><a class='link' href='#LaunchConfiguration'>LaunchConfiguration</a></code>
            </td>
        </tr>
</table>


#### Response {#Launcher.Launch_Response}

<table>
    <tr><th>Name</th><th>Type</th></tr>
        <tr>
            <td><code>result</code></td>
            <td>
                <code><a class='link' href='#Launcher_Launch_Result'>Launcher_Launch_Result</a></code>
            </td>
        </tr>
</table>

## Restarter {#Restarter}
*Defined in [fuchsia.session/launcher.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.session/launcher.fidl;l=47)*
<p>A protocol used to restart the currently running session.</p>


### Restart {#Restarter.Restart}

<p>Restarts the session.</p>
<ul>
<li>error <code>RestartError.NOT_RUNNING</code> if there is no
currently running session to restart.</li>
<li>error <code>RestartError.DESTROY_COMPONENT_FAILED</code> if an existing session component
could not be destroyed. The existing session remains running at this point.</li>
<li>error <code>RestartError.CREATE_COMPONENT_FAILED</code> if the session component
could not be started. No session will be running at this point.</li>
</ul>



#### Request {#Restarter.Restart_Request}

&lt;EMPTY&gt;


#### Response {#Restarter.Restart_Response}

<table>
    <tr><th>Name</th><th>Type</th></tr>
        <tr>
            <td><code>result</code></td>
            <td>
                <code><a class='link' href='#Restarter_Restart_Result'>Restarter_Restart_Result</a></code>
            </td>
        </tr>
</table>


## **STRUCTS**

### Launcher_Launch_Response  {#Launcher_Launch_Response data-text="Launcher_Launch_Response"}
*Defined in [fuchsia.session/launcher.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.session/launcher.fidl;l=27)*

&lt;EMPTY&gt;

### Restarter_Restart_Response  {#Restarter_Restart_Response data-text="Restarter_Restart_Response"}
*Defined in [fuchsia.session/launcher.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.session/launcher.fidl;l=56)*

&lt;EMPTY&gt;


## **ENUMS**

### LaunchError [flexible](/fuchsia-src/reference/fidl/language/language.md#strict-vs-flexible){:.fidl-attribute} {#LaunchError data-text="LaunchError"}
Type: <code>uint32</code>

*Defined in [fuchsia.session/launcher.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.session/launcher.fidl;l=31)*
<p>An error that occurs when launching a session.</p>

<table>
    <tr><th>Name</th><th>Value</th><th>Description</th></tr>
        <tr id="LaunchError.INVALID_ARGS">
<td><h3 id="LaunchError.INVALID_ARGS" class="add-link hide-from-toc">INVALID_ARGS</h3></td>
            <td><code>1</code></td>
            <td><p>The session's <code>LaunchConfiguration</code> is malformed.</p>
</td>
        </tr>
        <tr id="LaunchError.NOT_FOUND">
<td><h3 id="LaunchError.NOT_FOUND" class="add-link hide-from-toc">NOT_FOUND</h3></td>
            <td><code>2</code></td>
            <td><p>There was an error resolving the session's component URL.</p>
</td>
        </tr>
        <tr id="LaunchError.DESTROY_COMPONENT_FAILED">
<td><h3 id="LaunchError.DESTROY_COMPONENT_FAILED" class="add-link hide-from-toc">DESTROY_COMPONENT_FAILED</h3></td>
            <td><code>3</code></td>
            <td><p>The session component could not be destroyed.</p>
</td>
        </tr>
        <tr id="LaunchError.CREATE_COMPONENT_FAILED">
<td><h3 id="LaunchError.CREATE_COMPONENT_FAILED" class="add-link hide-from-toc">CREATE_COMPONENT_FAILED</h3></td>
            <td><code>4</code></td>
            <td><p>The session component could not be created.</p>
</td>
        </tr>
</table>

### RestartError [flexible](/fuchsia-src/reference/fidl/language/language.md#strict-vs-flexible){:.fidl-attribute} {#RestartError data-text="RestartError"}
Type: <code>uint32</code>

*Defined in [fuchsia.session/launcher.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.session/launcher.fidl;l=60)*
<p>An error that occurs when restarting a session.</p>

<table>
    <tr><th>Name</th><th>Value</th><th>Description</th></tr>
        <tr id="RestartError.NOT_RUNNING">
<td><h3 id="RestartError.NOT_RUNNING" class="add-link hide-from-toc">NOT_RUNNING</h3></td>
            <td><code>1</code></td>
            <td><p>There is no currently running session to restart.</p>
</td>
        </tr>
        <tr id="RestartError.NOT_FOUND">
<td><h3 id="RestartError.NOT_FOUND" class="add-link hide-from-toc">NOT_FOUND</h3></td>
            <td><code>2</code></td>
            <td><p>There was an error resolving the session's component URL.</p>
</td>
        </tr>
        <tr id="RestartError.DESTROY_COMPONENT_FAILED">
<td><h3 id="RestartError.DESTROY_COMPONENT_FAILED" class="add-link hide-from-toc">DESTROY_COMPONENT_FAILED</h3></td>
            <td><code>3</code></td>
            <td><p>The session component could not be destroyed.</p>
</td>
        </tr>
        <tr id="RestartError.CREATE_COMPONENT_FAILED">
<td><h3 id="RestartError.CREATE_COMPONENT_FAILED" class="add-link hide-from-toc">CREATE_COMPONENT_FAILED</h3></td>
            <td><code>4</code></td>
            <td><p>The session component could not be created.</p>
</td>
        </tr>
</table>


## **TABLES**

### LaunchConfiguration  {#LaunchConfiguration data-text="LaunchConfiguration"}


*Defined in [fuchsia.session/launcher.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.session/launcher.fidl;l=75)*
<p>Describes a session to launch.</p>

<table>
    <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
        <tr id="LaunchConfiguration.session_url">
<td><h3 id="LaunchConfiguration.session_url" class="add-link hide-from-toc">1</h3></td>
            <td><code>session_url</code></td>
            <td>
                <code>string[4096]</code>
            </td>
            <td><p>The component URL of the session.</p>
</td>
        </tr>
</table>


## **UNIONS**

### Launcher_Launch_Result [strict](/fuchsia-src/reference/fidl/language/language.md#strict-vs-flexible){:.fidl-attribute}  {#Launcher_Launch_Result data-text="Launcher_Launch_Result"}
*Defined in [fuchsia.session/launcher.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.session/launcher.fidl;l=27)*
<table>
    <tr><th>Ordinal</th><th>Variant</th><th>Type</th><th>Description</th></tr>
        <tr id="Launcher_Launch_Result.response">
<td><h3 id="Launcher_Launch_Result.response" class="add-link hide-from-toc">1</h3></td>
            <td><code>response</code></td>
            <td>
                <code><a class='link' href='#Launcher_Launch_Response'>Launcher_Launch_Response</a></code>
            </td>
            <td></td>
        </tr>
        <tr id="Launcher_Launch_Result.err">
<td><h3 id="Launcher_Launch_Result.err" class="add-link hide-from-toc">2</h3></td>
            <td><code>err</code></td>
            <td>
                <code><a class='link' href='#LaunchError'>LaunchError</a></code>
            </td>
            <td></td>
        </tr>
</table>

### Restarter_Restart_Result [strict](/fuchsia-src/reference/fidl/language/language.md#strict-vs-flexible){:.fidl-attribute}  {#Restarter_Restart_Result data-text="Restarter_Restart_Result"}
*Defined in [fuchsia.session/launcher.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.session/launcher.fidl;l=56)*
<table>
    <tr><th>Ordinal</th><th>Variant</th><th>Type</th><th>Description</th></tr>
        <tr id="Restarter_Restart_Result.response">
<td><h3 id="Restarter_Restart_Result.response" class="add-link hide-from-toc">1</h3></td>
            <td><code>response</code></td>
            <td>
                <code><a class='link' href='#Restarter_Restart_Response'>Restarter_Restart_Response</a></code>
            </td>
            <td></td>
        </tr>
        <tr id="Restarter_Restart_Result.err">
<td><h3 id="Restarter_Restart_Result.err" class="add-link hide-from-toc">2</h3></td>
            <td><code>err</code></td>
            <td>
                <code><a class='link' href='#RestartError'>RestartError</a></code>
            </td>
            <td></td>
        </tr>
</table>