Lambda monitoring
=================

Data for monitoring
-------------------


Now we monitor two types of events for monitoring: *request*  and *error*. First type is all requests, second is
failed requests only. Every event is a point in the time series. The point is represented as union of the following
data:

    - series name (now *requests* and *errors*)
    - start request time
    - tags, indexed data in storage, dictionary: keys - string tag names, values - string, integer, float
    - fields, non-indexed data in storage, dictionary: keys - string tag names, values - string, integer, float

*'Requests'* series. Triggered on every request. Each point contains data about corresponding request (execution time and etc).

    - tags

        +--------------+----------------------------------------------------------------------------+
        | tag name     |                                description                                 |
        +==============+============================================================================+
        | service      | always "lambda-<lambda-id>"                                                |
        +--------------+----------------------------------------------------------------------------+
        | route        | concatenation of a request method and a request resource (POST:/main)      |
        +--------------+----------------------------------------------------------------------------+
        | status_code  | http status code of response                                               |
        +--------------+----------------------------------------------------------------------------+

    - fields

        +----------------+------------------------+
        |     fields     |      description       |
        +================+========================+
        | request_id     | request id             |
        +----------------+------------------------+
        | execution_time | request execution time |
        +----------------+------------------------+

*'Errors'* series. Triggered on failed request. Each point contains *error_code* of luna error.

    - tags

        +--------------+----------------------------------------------------------------------------+
        | tag name     |                                description                                 |
        +==============+============================================================================+
        | service      | always "lambda-<lambda-id>"                                                |
        +--------------+----------------------------------------------------------------------------+
        | route        | concatenation of a request method and a request resource (POST:/main)      |
        +--------------+----------------------------------------------------------------------------+
        | status_code  | http status code of response                                               |
        +--------------+----------------------------------------------------------------------------+
        | error_code   | luna error code                                                            |
        +--------------+----------------------------------------------------------------------------+

    - fields

        +----------------+------------------------+
        |     fields     |      description       |
        +================+========================+
        | request_id     | request id             |
        +----------------+------------------------+


Custom Monitoring
-----------------


For base monitoring usage information see `monitoring <./monitoring.html>`_.

It is possible to create custom monitoring points.
For example, there is a need to send data about how long it took to download or process images.

It is possible to specify your own **series**, **tags** and **fields**,
but there will always be a mandatory **tag** "service" with the "lambda-<lambda-id>" value.

For add custom monitoring point follow steps:

 1) Add file **monitoring_points.py** to lambda archive with the following content:

    .. literalinclude:: examples/201/monitoring_lambda/lambda/monitoring_points.py
       :caption: monitoring_points.py
       :language: python

    There are several rules for this file:

        - The number of points can be any.
        - Each point class name may be specify by any unique name.
        - Each point class must be inherited by **CustomMonitoringPoint**
        - Each point class must contain **series** attribute to specify monitoring series.

 2) Set monitoring points from **monitoring_points.py** to **lambda_main.py** and specify **tags** and **fields**:

    There are several general rules for this file:

        - Enable monitoring. See **INFLUX_MONITORING** setting in basic `principles of configuration <./config.html>`_.
        - If monitoring is unavailable, the points will not be sent without any errors.
        - Specify tags by set dictionary with tags to **pointTags** named argument.
        - Specify fileds by set dictionary with fields to **pointFields** named argument.

    .. warning::

        There are diferencies between standalone, handlers and tasks lambda monitoring mechanism. See description below.

    Send points using **request.sendToMonitoring** function for **standalone** or **handlers** lambda:

    .. literalinclude:: examples/201/monitoring_lambda/lambda/lambda_main.py
       :caption: lambda_main.py
       :language: python

    .. literalinclude:: examples/201/monitoring_lambda/make_request.py
       :caption: request example
       :language: python

    Send points using **self.sendToMonitoring** function for **tasks** lambda:

      To run lambda tasks example, refer to the task processing description `here <./tasks.html#task-processing>`_.

    .. literalinclude:: examples/201/monitoring_lambda_task/lambda/lambda_main.py
       :caption: lambda_main.py
       :language: python

    .. literalinclude:: examples/201/monitoring_lambda_task/make_request.py
       :caption: request example
       :language: python


Database
--------

Monitoring is implemented as data sending to an `influx database <https://www.influxdata.com/products/influxdb-overview/>`_.