53 lines
2.6 KiB
ReStructuredText
53 lines
2.6 KiB
ReStructuredText
.. _lambda-fault-tolerance-sample-java:
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Diagrams of the Fault Tolerance Sample
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----------------------------------------------
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.. image:: ../images/faulttolerancesample-normal-flow.png
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*The above diagram illustrates the normal message flow.*
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**Normal flow:**
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======= ==================================================================================
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Step Description
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======= ==================================================================================
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1 The progress ``Listener`` starts the work.
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2 The ``Worker`` schedules work by sending ``Do`` messages periodically to itself
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3, 4, 5 When receiving ``Do`` the ``Worker`` tells the ``CounterService``
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to increment the counter, three times. The ``Increment`` message is forwarded
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to the ``Counter``, which updates its counter variable and sends current value
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to the ``Storage``.
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6, 7 The ``Worker`` asks the ``CounterService`` of current value of the counter and pipes
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the result back to the ``Listener``.
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======= ==================================================================================
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.. image:: ../images/faulttolerancesample-failure-flow.png
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*The above diagram illustrates what happens in case of storage failure.*
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**Failure flow:**
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=========== ==================================================================================
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Step Description
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=========== ==================================================================================
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1 The ``Storage`` throws ``StorageException``.
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2 The ``CounterService`` is supervisor of the ``Storage`` and restarts the
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``Storage`` when ``StorageException`` is thrown.
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3, 4, 5, 6 The ``Storage`` continues to fail and is restarted.
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7 After 3 failures and restarts within 5 seconds the ``Storage`` is stopped by its
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supervisor, i.e. the ``CounterService``.
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8 The ``CounterService`` is also watching the ``Storage`` for termination and
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receives the ``Terminated`` message when the ``Storage`` has been stopped ...
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9, 10, 11 and tells the ``Counter`` that there is no ``Storage``.
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12 The ``CounterService`` schedules a ``Reconnect`` message to itself.
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13, 14 When it receives the ``Reconnect`` message it creates a new ``Storage`` ...
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15, 16 and tells the ``Counter`` to use the new ``Storage``
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=========== ==================================================================================
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Full Source Code of the Fault Tolerance Sample
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------------------------------------------------------
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.. includecode:: ../../../akka-samples/akka-docs-java-lambda/src/test/java/docs/actor/japi/FaultHandlingDocSample.java#all
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