Source code for sosw.managers.meta_handler

"""
..  hidden-code-block:: text
    :label: View Licence Agreement <br>

    sosw - Serverless Orchestrator of Serverless Workers

    The MIT License (MIT)
    Copyright (C) 2024  sosw core contributors <info@sosw.app>

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
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"""

__all__ = ['MetaHandler']
__author__ = "Mark Bulgakov, Nikolay Grishchenko"
__version__ = "1.0"

try:
    from aws_lambda_powertools import Logger

    logger = Logger()

except ImportError:
    import logging

    logger = logging.getLogger()
    logger.setLevel(logging.INFO)

import time


from sosw.app import global_vars
from sosw.components.dynamo_db import DynamoDbClient
from sosw.components.helpers import recursive_update
from typing import Dict




class MetaHandler:
    """
    MetaHandler is helper class for Essential classes.
    It works with DynamoDB table to store the meta data of operations on Tasks.
    """

    DEFAULT_CONFIG = {
        'write_meta_to_ddb': True,
        'dynamo_db_config': {
            'table_name': 'sosw_tasks_meta',
            'hash_key': 'task_id',
            'row_mapper': {
                'task_id': 'S',
                'created_at': 'N',
                'author': 'S',
                'invocation_id': 'S',
                'log_stream_name': 'S',
                'action': 'S'
            },
            'required_fields': [
                'task_id',
                'created_at',
                'author',
                'invocation_id',
                'log_stream_name',
                'action'
            ],
        },
    }

    AVAILABLE_ACTIONS_MAPPING = {}
    CONTEXT_FIELDS_MAPPINGS = {
        'author': 'function_name',
        'invocation_id': 'aws_request_id',
        'log_stream_name': 'log_stream_name'
    }

    def __init__(self, custom_config: Dict = None, **kwargs):

        # Initialize config from default config
        self.config = self.DEFAULT_CONFIG or {}

        # Update config recursively from custom config
        self.config = recursive_update(self.config, custom_config or {})

        if self.config['write_meta_to_ddb']:
            try:
                self.dynamo_db_client = DynamoDbClient(config=self.config['dynamo_db_config'])
            except:
                logging.exception("Failed to initialize MetaHandler DynamoDbClient")
                self.dynamo_db_client = None
        else:
            self.dynamo_db_client = None

        logger.info("Initialized MetaHandler with config %s and DynamoDbClient %s", self.config, self.dynamo_db_client)




    def post(self, task_id: str, action: str, **kwargs):
        """
        Write row with meta data to sosw_tasks_meta DynamoDB Table if configured.
        As long as collecting the meta data is optional, the MetaHandler will either save it
        to DynamoDB or just log.

        MetaHandler does not restrict the fields and actions you can post from your Worker Lambdas with the exception of
        the following built-in fields. These ones are always taken from the current ``lambda_context`` automatically.

         * ``'author'``
         * ``'invocation_id'``
         * ``'log_stream_name'``
        """

        row = {
            'task_id': task_id,
            'created_at': time.time(),
            'action': self._ma(action)
        }

        assert not set(kwargs).intersection(set(self.CONTEXT_FIELDS_MAPPINGS)), \
            'args from lambda_context should not be passed'

        for field, value in kwargs.items():
            row[field] = value

        for field, mapping in self.CONTEXT_FIELDS_MAPPINGS.items():
            row[field] = getattr(global_vars.lambda_context, mapping)

        if self.dynamo_db_client:
            self.dynamo_db_client.create(row=row)
        else:
            logger.info("DynamoDB client/table is not configured for meta_handler. Skip saving task meta data: %s", row)


    def _ma(self, field_name):
        # FIXMEONEDAY: implement mappings for the actions names
        return str(field_name)