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Examples of Action Configuration

This section includes several examples of fully-configured actions, using the elements as outlined in the previous sections.

Archive Journals Once a Week

The listing below asks AMPS to archive transaction log journal files older than 1 week, every Saturday at 12:30 AM.

This configuration moves journal files from the JournalDirectory to the JournalArchiveDirectory, while maintaining the files as an active part of the transaction log (ensuring that they are still available for bookmark replay, replication, and so on).

<Actions>
    <Action>
        <On>
            <Module>amps-action-on-schedule</Module>
            <Options>
                <Every>Saturday at 00:30</Every>
                <Name>Saturday Night Fever</Name>
            </Options>
        </On>
        <Do>
            <Module>amps-action-do-archive-journal</Module>
            <Options>
                <Age>7d</Age>
            </Options>
        </Do>
    </Action>
</Actions>

Archive Journals On RESTful Command

The listing below directs AMPS to archive journals when a query is made to the /amps/administrator/actions/archive_journals resource. The request must include an AGE query parameter. When the request is submitted, AMPS will mark journals older than the specified age for archival.

<Actions>
    <Action>
        <On>
            <Module>amps-action-on-admin</Module>
            <Options>
                <Path>archive_journals</Path>
                <RequiredParameter>AGE</RequiredParameter>
                <Name>Archive Journals</Name>
            </Options>
        </On>
        <Do>
            <Module>amps-action-do-archive-journal</Module>
            <Options>
                <Age>{{AGE}}</Age>
            </Options>
        </Do>
    </Action>
</Actions>

The On configuration for this action specifies that the action will run when a request is made to the /amps/administrator/actions/archive_journals resource, and that the request must contain an AGE query parameter. When the request runs, the AGE parameter is added to the context for the action.

The Do configuration for this action runs the amps-action-do-archive-journal module, and fills in the value of the AGE parameter provided by the HTTP request.

If the AGE parameter is missing, the amps-action-on-admin module will refuse the request.

If the AGE parameter is not a valid interval (for example, if someone provided the string "LastThursday" instead of a valid AMPS interval like 48h), the amps-action-do-archive-journal module will log an error and refuse to run the request.

Record Expired Queue Messages to a Dead Letter Topic

The listing below detects when a message expires from a queue, and publishes those messages to a dead letter topic.

<Actions>
    <Action>
        <On>
            <Module>amps-action-on-sow-expire-message</Module>
            <Options>
                <Topic>interesting-queue</Topic>
                <MessageType>json</MessageType>
            </Options>
        </On>
        <On>
            <Module>amps-action-on-sow-expire-message</Module>
            <Options>
                <Topic>another-interesting-queue</Topic>
                <MessageType>json</MessageType>
            </Options>
        </On>
        <Do>
            <Module>amps-action-do-publish-message</Module>
            <Options>
                <Topic>dead-letter</Topic>
                <MessageType>json</MessageType>
                <Data>{"topic":"{{AMPS_TOPIC}}","message":{{AMPS_DATA}} }</Data>
            </Options>
        </Do>
    </Action>
</Actions>

Copy Messages that Exceed a Timeout to a Different Topic

The listing below, in effect, copies messages from the Orders topic to the Orders_Stale topic when the status has been PENDING for more than 5 seconds.

<Actions>
    <Action>
        <On>
            <Module>amps-action-on-message-condition-timeout</Module>
            <Options>
                <MessageType>nvfix</MessageType>
                <Topic>Orders</Topic>
                <Filter>/status = 'PENDING'</Filter>
                <Duration>5s</Duration>
            </Options>
        </On>
        <Do>
            <Module>amps-action-do-publish-message</Module>
            <Options>
                <MessageType>nvfix</MessageType>
                <Topic>Orders_Stale</Topic>
                <Data>{{AMPS_DATA}}</Data>
            </Options>
        </Do>
    </Action>
</Actions>

Deactivate and Reactivate Security on Signals

The listing below disables authentication and entitlement when AMPS receives the USR1 signal. When AMPS receives the USR2 signal, AMPS re-enables authentication and entitlement. This configuration is, in effect, the configuration that AMPS installs by default for these signals.

<Actions>
    <Action>
        <On>
            <Module>amps-action-on-signal</Module>
            <Options>
                <Signal>SIGUSR1</Signal>
            </Options>
        </On>
        <Do>
            <Module>amps-action-do-disable-authentication</Module>
        </Do>
        <Do>
            <Module>amps-action-do-disable-entitlement</Module>
        </Do>
    </Action>
    <Action>
        <On>
            <Module>amps-action-on-signal</Module>
            <Options>
                <Signal>SIGUSR2</Signal>
            </Options>
        </On>
        <Do>
            <Module>amps-action-do-enable-authentication</Module>
        </Do>
        <Do>
            <Module>amps-action-do-enable-entitlement</Module>
        </Do>
    </Action>
</Actions>

Reset Entitlements for a Disconnected Client

The listing below resets entitlement cache for a user when a client with that authentication ID is disconnected. This is a practical approach when an application expects that each user will have a single connection to AMPS.

<Actions>
    <Action>
        <On>
            <Module>amps-action-on-disconnect-client</Module>
        </On>
        <Do>
            <Module>amps-action-do-reset-entitlement</Module>
            <Options>
                <AuthenticationId>{{AMPS_AUTHENTICATION_ID}}</AuthenticationId>
            </Options>
        </Do>
    </Action>
</Actions>

Extract Values from a Published Message

The listing below extracts values from a locally published xml message and stores them into VALUE.

<Actions>
    <Action>
        <On>
            <Module>amps-action-on-publish-message</Module>
            <Options>
                <Topic>message-sow</Topic>
                <MessageType>xml</MessageType>
                <MessageSource>local</MessageSource>
            </Options>
        </On>
        <Do>
            <Module>amps-action-do-extract-values</Module>
            <Options>
                <MessageType>xml</MessageType>
                <Data>{{AMPS_DATA}}</Data>
                <Value>VALUE = /VALUE</Value>
            </Options>
        </Do>
    </Action>
</Actions>

Shut Down AMPS When a Filesystem Is Full

The listing below directs AMPS to perform a graceful shutdown when the filesystem becomes full, with a check run every 3 seconds.

Increment a Counter and Echo a Message

The listing below increments a counter and echoes the counter's value when AMPS receives the USR1 signal.

<Actions>
    <Action>
        <On>
            <Module>amps-action-on-signal</Module>
            <Options>
                <Signal>SIGUSR1</Signal>
            </Options>
        </On>
        <Do>
            <Module>amps-action-do-increment-counter</Module>
            <Options>
                <Key>MY_COUNTER</Key>
                <Value>CURRENT_COUNTER_VALUE</Value>
            </Options>
        </Do>
        <Do>
            <Module>amps-action-do-echo-message</Module>
            <Options>
                <Message>AMPS has gotten {{CURRENT_COUNTER_VALUE}}
                    SIGUSR1 signals.</Message>
            </Options>
        </Do>
    </Action>
</Actions>