f9/sdk/fidl/fuchsia.update/README.md

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[TOC]
# fuchsia.update

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

## **PROTOCOLS**

## AttemptsMonitor {#AttemptsMonitor}
*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=104)*
<p>Monitors update attempts as they start.</p>
<p>Clients interested in receiving progress information for an update check
should implement this protocol and provide the client end to
<a class='link' href='#Manager.MonitorAllUpdateChecks'>Manager.MonitorAllUpdateChecks</a>.
The Manager will close the client end of the AttemptsMonitor if there are
more than 2 outstanding requests.</p>

### OnStart {#AttemptsMonitor.OnStart}

<p>Called when a new update attempt has started.</p>
<p>Arguments:</p>
<ul>
<li>|options| Options for how this request should be performed.</li>
<li>|monitor| A protocol on which to receive progress updates.</li>
</ul>

#### Request {#AttemptsMonitor.OnStart_Request}

<table>
    <tr><th>Name</th><th>Type</th></tr>
        <tr>
            <td><code>options</code></td>
            <td>
                <code><a class='link' href='#AttemptOptions'>AttemptOptions</a></code>
            </td>
        </tr>
        <tr>
            <td><code>monitor</code></td>
            <td>
                <code>server_end&lt;<a class='link' href='#Monitor'>Monitor</a>&gt;</code>
            </td>
        </tr>
</table>


#### Response {#AttemptsMonitor.OnStart_Response}

&lt;EMPTY&gt;

## CommitStatusProvider {#CommitStatusProvider}
*Defined in [fuchsia.update/commit.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/commit.fidl;l=19)*
<p>A reporter for whether the currently booted system is committed. When an
update is committed, this means:</p>
<ul>
<li>The currently booted slot is marked as healthy (e.g. successfully booted).</li>
<li>The alternate slot (if present) is marked as unbootable.</li>
<li>The system will not roll back to the previous version of the OS on reboot.</li>
<li>The previous version of the OS may be garbage collected.</li>
</ul>
<p>Until the update is committed, the system retains the prior version of the OS.
That way, if we discover the newly written version is bad (e.g. it cannot itself
update), then the system can fall back to the previous committed version.</p>

### IsCurrentSystemCommitted {#CommitStatusProvider.IsCurrentSystemCommitted}

<p>Determines whether the currently booted system is committed, and immediately
returns an EventPair.</p>
<ul>
<li>If the currently booted system is committed, the <code>ZX_USER_SIGNAL_0</code> signal
is asserted on the EventPair, e.g. the signal is asserted before the
EventPair is returned.</li>
<li>If the commit is pending, no signals are asserted on the EventPair. When the
system is committed, <code>ZX_USER_SIGNAL_0</code> is asserted on the EventPair.</li>
<li>If the system fails to commit the currently booted version, the system
will reboot and terminate the component serving <a class='link' href='#CommitStatusProvider'>CommitStatusProvider</a>,
which will assert <code>ZX_EVENTPAIR_PEER_CLOSED</code>. At this point, any remaining
EventPairs will observe the <code>ZX_EVENTPAIR_PEER_CLOSED</code> signal.</li>
</ul>
<ul>
<li>response <code>event</code> an EventPair with rights <code>ZX_RIGHTS_BASIC</code>.</li>
</ul>

#### Request {#CommitStatusProvider.IsCurrentSystemCommitted_Request}

&lt;EMPTY&gt;


#### Response {#CommitStatusProvider.IsCurrentSystemCommitted_Response}

<table>
    <tr><th>Name</th><th>Type</th></tr>
        <tr>
            <td><code>event</code></td>
            <td>
                <code>handle&lt;eventpair&gt;</code>
            </td>
        </tr>
</table>

## Manager {#Manager}
*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=12)*
<p>The Manager protocol is used by a client that wishes to either check for an
update, or follow the status of ongoing updates.</p>
<p>The Manager provides a mechanism for checking for updates via the
<a class='link' href='#Manager.CheckNow'>Manager.CheckNow</a> message.</p>

### CheckNow {#Manager.CheckNow}

<p>Immediately check for an update, and optionally track the state and
progress of that update check.</p>
<ul>
<li>
<p>request <code>options</code> Options for how this request should be performed.
E.g. What kind of entity initiated this request?
E.g. Is monitoring an existing update check that
is already in process an acceptable
alternative?</p>
</li>
<li>
<p>request <code>monitor</code> An interface on which to receive the status events
for this update check.  The monitor is only valid
for this single update check, after that it will
not receive any more notifications and will be
closed.</p>
</li>
</ul>
<ul>
<li>error If an update check cannot be started, an error will be returned.
The <a class='link' href='#Monitor'>Monitor</a>, if provided, will not receive any notifications.</li>
</ul>

#### Request {#Manager.CheckNow_Request}

<table>
    <tr><th>Name</th><th>Type</th></tr>
        <tr>
            <td><code>options</code></td>
            <td>
                <code><a class='link' href='#CheckOptions'>CheckOptions</a></code>
            </td>
        </tr>
        <tr>
            <td><code>monitor</code></td>
            <td>
                <code><a class='link' href='#Monitor'>Monitor</a>?</code>
            </td>
        </tr>
</table>


#### Response {#Manager.CheckNow_Response}

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

### MonitorAllUpdateChecks {#Manager.MonitorAllUpdateChecks}

<p>Monitor all update attempts as they start, as well as an in-progress
attempt, if there is one.</p>
<p>Arguments:</p>
<ul>
<li>|attempts_monitor| A protocol on which to receive |Monitor| instances
as update attempts start.</li>
</ul>

#### Request {#Manager.MonitorAllUpdateChecks_Request}

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


### PerformPendingReboot {#Manager.PerformPendingReboot}

<p>Performs any pending reboot of the system into an updated OS, if an
update has been staged for the next system startup.</p>
<p>Should be used when the platform is configured to let the product drive
reboot scheduling. If this method is called when the platform is not
configured to let the product drive reboot scheduling, no reboot will
occur, and the system will reboot on its own after an update.</p>
<p>In product-driven reboot configurations, the platform still contains a
backstop for post-update reboots. This means that if an update
is installed but the system has not rebooted before the backstop
duration occurs, the update system will automatically reboot the
system as a security measure. To avoid hitting this backstop,
products which desire control over reboot timing should call this
method roughly daily.</p>
<ul>
<li>response <code>rebooting</code> true if the system is rebooting, false if no
update was pending reboot.</li>
</ul>

#### Request {#Manager.PerformPendingReboot_Request}

&lt;EMPTY&gt;


#### Response {#Manager.PerformPendingReboot_Response}

<table>
    <tr><th>Name</th><th>Type</th></tr>
        <tr>
            <td><code>rebooting</code></td>
            <td>
                <code>bool</code>
            </td>
        </tr>
</table>

## Monitor {#Monitor}
*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=128)*
<p>Monitors a single update check.</p>
<p>Clients interested in receiving progress information for an update check
should implement this protocol and provide the client end to
<a class='link' href='#Manager.CheckNow'>Manager.CheckNow</a>.</p>

### OnState {#Monitor.OnState}

<p>Receives a status update for this update check.</p>
<p>This request will be called for all state changes, skipping none.
However, message delivery is throttled by the rate at which the
implementation acknowledges the messages.</p>
<p>The throttled delivery doesn't impact the underlying state of the
<a class='link' href='#Manager'>Manager</a>.  It does not wait for any acknowledgements before it moves
on to the next state in its state machine.  The <a class='link' href='#Manager'>Manager</a> will simply
queue up the states for the <a class='link' href='#Monitor'>Monitor</a> implementation to receive.</p>
<p>During the installing_update state, the <a class='link' href='#Manager'>Manager</a> may, at its
discretion, collapse redundant information like the fraction completed,
in the event that the <a class='link' href='#Monitor'>Monitor</a> implementation is not responding to
the <code>OnState()</code> requests in a timely manner.</p>
<ul>
<li>request <code>state</code> The new state of the update check.</li>
</ul>
<ul>
<li>response        The implementation is ready to receive the next
<a class='link' href='#State'>State</a> from the <a class='link' href='#Manager'>Manager</a>.</li>
</ul>

#### Request {#Monitor.OnState_Request}

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


#### Response {#Monitor.OnState_Response}

&lt;EMPTY&gt;


## **STRUCTS**

### Manager_CheckNow_Response  {#Manager_CheckNow_Response data-text="Manager_CheckNow_Response"}
*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=33)*

&lt;EMPTY&gt;


## **ENUMS**

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

*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=297)*
<p>This is the set of values that are returned by an request to immediately
check for an update.</p>

<table>
    <tr><th>Name</th><th>Value</th><th>Description</th></tr>
        <tr id="CheckNotStartedReason.INTERNAL">
<td><h3 id="CheckNotStartedReason.INTERNAL" class="add-link hide-from-toc">INTERNAL</h3></td>
            <td><code>1</code></td>
            <td><p>There was an internal error in starting the update check.  The client
is not expected to be able to do something meaningful about this error,
except to try again later (after an appropriate delay and back-off in
the event of multiple errors.</p>
</td>
        </tr>
        <tr id="CheckNotStartedReason.INVALID_OPTIONS">
<td><h3 id="CheckNotStartedReason.INVALID_OPTIONS" class="add-link hide-from-toc">INVALID_OPTIONS</h3></td>
            <td><code>2</code></td>
            <td><p>If there are required arguments or options (or option values in
conflict), provided via the CheckOptions table to CheckNow, this error
will be returned.</p>
</td>
        </tr>
        <tr id="CheckNotStartedReason.ALREADY_IN_PROGRESS">
<td><h3 id="CheckNotStartedReason.ALREADY_IN_PROGRESS" class="add-link hide-from-toc">ALREADY_IN_PROGRESS</h3></td>
            <td><code>3</code></td>
            <td><p>There was already another update check in progress when this request was
made.  A new update check will not be started.</p>
</td>
        </tr>
        <tr id="CheckNotStartedReason.THROTTLED">
<td><h3 id="CheckNotStartedReason.THROTTLED" class="add-link hide-from-toc">THROTTLED</h3></td>
            <td><code>4</code></td>
            <td><p>The update check was not started, because too many requests to check for
updates have been made by clients in a short period of time.</p>
<p><strong>NOTE:</strong> Clients MUST NOT attempt to cause background update checks to
happen at a more frequent rate than the fuchsia.update.Manager will do
them.</p>
<p>If a client attempts to abuse this, it will be throttled.</p>
</td>
        </tr>
</table>

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

*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=85)*
<p>Who or what initiated the update check.</p>

<table>
    <tr><th>Name</th><th>Value</th><th>Description</th></tr>
        <tr id="Initiator.USER">
<td><h3 id="Initiator.USER" class="add-link hide-from-toc">USER</h3></td>
            <td><code>1</code></td>
            <td><p>The update check was initiated by an interactive user, or the user is
otherwise blocked and waiting for the result of this update check.  This
SHOULD only be used when there is a UI element or flow that a user has
interacted with which has initiated this update check.</p>
</td>
        </tr>
        <tr id="Initiator.SERVICE">
<td><h3 id="Initiator.SERVICE" class="add-link hide-from-toc">SERVICE</h3></td>
            <td><code>2</code></td>
            <td><p>The update check was initiated by a service, not a user-facing aspect
of the system.</p>
</td>
        </tr>
</table>

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

*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=327)*
<p>This is the set of values that are provided when an update installation
is deferred.</p>

<table>
    <tr><th>Name</th><th>Value</th><th>Description</th></tr>
        <tr id="InstallationDeferralReason.CURRENT_SYSTEM_NOT_COMMITTED">
<td><h3 id="InstallationDeferralReason.CURRENT_SYSTEM_NOT_COMMITTED" class="add-link hide-from-toc">CURRENT_SYSTEM_NOT_COMMITTED</h3></td>
            <td><code>1</code></td>
            <td><p>The update was not installed because the currently booted system is not
committed. Consumers are encouraged to use the <a class='link' href='#CommitStatusProvider'>CommitStatusProvider</a>
to determine when to retry the update check such that the update will
be installed.</p>
</td>
        </tr>
</table>


## **TABLES**

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


*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=117)*
<p>Details for an update attempt monitor.</p>

<table>
    <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
        <tr id="AttemptOptions.initiator">
<td><h3 id="AttemptOptions.initiator" class="add-link hide-from-toc">1</h3></td>
            <td><code>initiator</code></td>
            <td>
                <code><a class='link' href='#Initiator'>Initiator</a></code>
            </td>
            <td><p>Who or what initiated this update attempt.  This may influence how the
update check is performed.</p>
</td>
        </tr>
</table>

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


*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=69)*
<p>Configuration options for an update check.</p>

<table>
    <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
        <tr id="CheckOptions.initiator">
<td><h3 id="CheckOptions.initiator" class="add-link hide-from-toc">1</h3></td>
            <td><code>initiator</code></td>
            <td>
                <code><a class='link' href='#Initiator'>Initiator</a></code>
            </td>
            <td><p>Who or what initiated this update attempt.  This is taken as input to
Policy, and may influence how the update check is performed.</p>
<p><strong>This is a required field.</strong></p>
</td>
        </tr>
        <tr id="CheckOptions.allow_attaching_to_existing_update_check">
<td><h3 id="CheckOptions.allow_attaching_to_existing_update_check" class="add-link hide-from-toc">2</h3></td>
            <td><code>allow_attaching_to_existing_update_check</code></td>
            <td>
                <code>bool</code>
            </td>
            <td><p>If an update check is already in progress, it's acceptable to instead
attach a Monitor to that in-progress update instead of failing this
request to check for updates.  This may convert situations that would
have resulted in the ALREADY_IN_PROGRESS to be treated as non-error
cases.</p>
</td>
        </tr>
</table>

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


*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=237)*
<p>This is the set of data associated with <code>checking_for_updates</code>.
(currently none)</p>

<table>
    <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
</table>

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


*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=242)*
<p>This is the set of data associated with the <code>error_checking_for_update</code>
state.
(currently none)</p>

<table>
    <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
</table>

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


*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=250)*
<p>This is the set of data associated with the
<code>installation_deferred_by_policy</code> state.</p>

<table>
    <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
        <tr id="InstallationDeferredData.update">
<td><h3 id="InstallationDeferredData.update" class="add-link hide-from-toc">1</h3></td>
            <td><code>update</code></td>
            <td>
                <code><a class='link' href='#UpdateInfo'>UpdateInfo</a></code>
            </td>
            <td></td>
        </tr>
        <tr id="InstallationDeferredData.deferral_reason">
<td><h3 id="InstallationDeferredData.deferral_reason" class="add-link hide-from-toc">2</h3></td>
            <td><code>deferral_reason</code></td>
            <td>
                <code><a class='link' href='#InstallationDeferralReason'>InstallationDeferralReason</a></code>
            </td>
            <td></td>
        </tr>
</table>

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


*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=266)*
<p>This is the set of data associated with the <code>installation_error</code> state.
(currently none)</p>

<table>
    <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
        <tr id="InstallationErrorData.update">
<td><h3 id="InstallationErrorData.update" class="add-link hide-from-toc">1</h3></td>
            <td><code>update</code></td>
            <td>
                <code><a class='link' href='#UpdateInfo'>UpdateInfo</a></code>
            </td>
            <td></td>
        </tr>
        <tr id="InstallationErrorData.installation_progress">
<td><h3 id="InstallationErrorData.installation_progress" class="add-link hide-from-toc">2</h3></td>
            <td><code>installation_progress</code></td>
            <td>
                <code><a class='link' href='#InstallationProgress'>InstallationProgress</a></code>
            </td>
            <td></td>
        </tr>
</table>

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


*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=290)*
<p>This describes the progress installing the update that has been made so far.</p>

<table>
    <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
        <tr id="InstallationProgress.fraction_completed">
<td><h3 id="InstallationProgress.fraction_completed" class="add-link hide-from-toc">1</h3></td>
            <td><code>fraction_completed</code></td>
            <td>
                <code>float32</code>
            </td>
            <td><p>The fraction [0-1.0f] of the installation that has been completed.</p>
</td>
        </tr>
</table>

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


*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=259)*
<p>This is the set of data associated with the states involved with installing
an update:</p>
<ul>
<li><code>installing_update</code></li>
<li><code>waiting_for_reboot</code></li>
</ul>

<table>
    <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
        <tr id="InstallingData.update">
<td><h3 id="InstallingData.update" class="add-link hide-from-toc">1</h3></td>
            <td><code>update</code></td>
            <td>
                <code><a class='link' href='#UpdateInfo'>UpdateInfo</a></code>
            </td>
            <td></td>
        </tr>
        <tr id="InstallingData.installation_progress">
<td><h3 id="InstallingData.installation_progress" class="add-link hide-from-toc">2</h3></td>
            <td><code>installation_progress</code></td>
            <td>
                <code><a class='link' href='#InstallationProgress'>InstallationProgress</a></code>
            </td>
            <td></td>
        </tr>
</table>

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


*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=246)*
<p>This is the set of data associated with the <code>no_update_available</code> state.
(currently none)</p>

<table>
    <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
</table>

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


*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=272)*
<p>This describes the update that is available to be installed.</p>

<table>
    <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
        <tr id="UpdateInfo.version_available">
<td><h3 id="UpdateInfo.version_available" class="add-link hide-from-toc">1</h3></td>
            <td><code>version_available</code></td>
            <td>
                <code>string[128]</code>
            </td>
            <td><p>A string that describes the version that is available.  This may be
either a semantic version (A.B.C.D) or an opaque hash.  Clients MUST
not attempt to inspect this value, it is for display purposes only.</p>
</td>
        </tr>
        <tr id="UpdateInfo.download_size">
<td><h3 id="UpdateInfo.download_size" class="add-link hide-from-toc">2</h3></td>
            <td><code>download_size</code></td>
            <td>
                <code>uint64</code>
            </td>
            <td><p>The total number of bytes that may be downloaded to apply this update.</p>
</td>
        </tr>
        <tr id="UpdateInfo.urgent">
<td><h3 id="UpdateInfo.urgent" class="add-link hide-from-toc">3</h3></td>
            <td><code>urgent</code></td>
            <td>
                <code>bool</code>
            </td>
            <td><p>Whether the update was marked as urgent. Default is false.</p>
</td>
        </tr>
</table>


## **UNIONS**

### Manager_CheckNow_Result [strict](/fuchsia-src/reference/fidl/language/language.md#strict-vs-flexible){:.fidl-attribute}  {#Manager_CheckNow_Result data-text="Manager_CheckNow_Result"}
*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=33)*
<table>
    <tr><th>Ordinal</th><th>Variant</th><th>Type</th><th>Description</th></tr>
        <tr id="Manager_CheckNow_Result.response">
<td><h3 id="Manager_CheckNow_Result.response" class="add-link hide-from-toc">1</h3></td>
            <td><code>response</code></td>
            <td>
                <code><a class='link' href='#Manager_CheckNow_Response'>Manager_CheckNow_Response</a></code>
            </td>
            <td></td>
        </tr>
        <tr id="Manager_CheckNow_Result.err">
<td><h3 id="Manager_CheckNow_Result.err" class="add-link hide-from-toc">2</h3></td>
            <td><code>err</code></td>
            <td>
                <code><a class='link' href='#CheckNotStartedReason'>CheckNotStartedReason</a></code>
            </td>
            <td></td>
        </tr>
</table>

### State [strict](/fuchsia-src/reference/fidl/language/language.md#strict-vs-flexible){:.fidl-attribute}  {#State data-text="State"}
*Defined in [fuchsia.update/update.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=182)*
<p>The set of states that a <a class='link' href='#Monitor'>Monitor</a> can receive during an update check.</p>
<p>An update check ends when it enters a terminal state, denoted below as the
states on the right-hand side of the diagram with no arrows leading out of
them.</p>
<h1>State Machine Diagram</h1>
<pre><code>    +----------------------+     +---------------------------------+
    | checking_for_updates |----&gt;|    error_checking_for_update    |
    +----------------------+     +---------------------------------+
               |
               |                 +---------------------------------+
               +----------------&gt;|       no_update_available       |
               |                 +---------------------------------+
               |
               |                 +---------------------------------+
               +----------------&gt;| installation_deferred_by_policy |
               |                 +---------------------------------+
               v
    +----------------------+     +---------------------------------+
    |  installing_update   |----&gt;|       installation_error        |
    +----------------------+     +---------------------------------+
               |
               |                 +---------------------------------+
               +----------------&gt;|       waiting_for_reboot        |
                                 +---------------------------------+
</code></pre>
<table>
    <tr><th>Ordinal</th><th>Variant</th><th>Type</th><th>Description</th></tr>
        <tr id="State.checking_for_updates">
<td><h3 id="State.checking_for_updates" class="add-link hide-from-toc">1</h3></td>
            <td><code>checking_for_updates</code></td>
            <td>
                <code><a class='link' href='#CheckingForUpdatesData'>CheckingForUpdatesData</a></code>
            </td>
            <td><p>The Manager is currently checking for an update.</p>
<p>Next states:</p>
<ul>
<li><code>installing_update</code> update is available and allowed by policy</li>
<li><code>error_checking_for_update</code> on error</li>
<li><code>update_deferred_by_policy</code> update is available but deferred by policy</li>
</ul>
</td>
        </tr>
        <tr id="State.error_checking_for_update">
<td><h3 id="State.error_checking_for_update" class="add-link hide-from-toc">2</h3></td>
            <td><code>error_checking_for_update</code></td>
            <td>
                <code><a class='link' href='#ErrorCheckingForUpdateData'>ErrorCheckingForUpdateData</a></code>
            </td>
            <td><p>The Manager encountered an error while checking for the existence of a
a new update.</p>
<p><strong>This is a terminal state</strong></p>
</td>
        </tr>
        <tr id="State.no_update_available">
<td><h3 id="State.no_update_available" class="add-link hide-from-toc">3</h3></td>
            <td><code>no_update_available</code></td>
            <td>
                <code><a class='link' href='#NoUpdateAvailableData'>NoUpdateAvailableData</a></code>
            </td>
            <td><p>There is not update available at this time.</p>
<p><strong>This is a terminal state</strong></p>
</td>
        </tr>
        <tr id="State.installation_deferred_by_policy">
<td><h3 id="State.installation_deferred_by_policy" class="add-link hide-from-toc">4</h3></td>
            <td><code>installation_deferred_by_policy</code></td>
            <td>
                <code><a class='link' href='#InstallationDeferredData'>InstallationDeferredData</a></code>
            </td>
            <td><p>The Manager has found an available update but is not acting on it at
this time due to policy restrictions.</p>
<p><strong>This is a terminal state</strong></p>
</td>
        </tr>
        <tr id="State.installing_update">
<td><h3 id="State.installing_update" class="add-link hide-from-toc">5</h3></td>
            <td><code>installing_update</code></td>
            <td>
                <code><a class='link' href='#InstallingData'>InstallingData</a></code>
            </td>
            <td><p>The Manager is installing the available update.</p>
<p>Next states:</p>
<ul>
<li><code>waiting_for_reboot</code> on success</li>
<li><code>installation_error</code> on error</li>
</ul>
</td>
        </tr>
        <tr id="State.waiting_for_reboot">
<td><h3 id="State.waiting_for_reboot" class="add-link hide-from-toc">6</h3></td>
            <td><code>waiting_for_reboot</code></td>
            <td>
                <code><a class='link' href='#InstallingData'>InstallingData</a></code>
            </td>
            <td><p>The update has been installed, and the device is waiting to be rebooted.</p>
<p>Next states:</p>
<ul>
<li>(none, the device reboots)</li>
</ul>
<p><strong>This is a terminal state</strong></p>
</td>
        </tr>
        <tr id="State.installation_error">
<td><h3 id="State.installation_error" class="add-link hide-from-toc">7</h3></td>
            <td><code>installation_error</code></td>
            <td>
                <code><a class='link' href='#InstallationErrorData'>InstallationErrorData</a></code>
            </td>
            <td><p>The Manager encountered an update in the installation of the update.</p>
<p><strong>This is a terminal state</strong></p>
</td>
        </tr>
</table>



## **CONSTANTS**

<table>
    <tr><th>Name</th><th>Value</th><th>Type</th><th>Description</th></tr>
        <tr id="MAX_VERSION_STRING_SIZE">
            <td><a href="https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.update/update.fidl;l=287">MAX_VERSION_STRING_SIZE</a></td>
                <td>
                    <code>128</code>
                </td>
                <td><code>uint32</code></td>
            <td><p>This is the maximum length of a version string that will be returned by the
protocol</p>
</td>
        </tr>
</table>