config.yml

monolog:
    handlers:
        app:
            type:     stream
            path:     "%kernel.logs_dir%/%kernel.environment%_app.log"
            level:    debug
            channels: ["!event", "!request", "!security"]
            formatter: app.line_formatter
            excluded_404s:
                - .*
        app_verbose:
            type:     stream
            #path:     "%kernel.logs_dir%/%kernel.environment%_app_verbose.log"
            path:     "php://stderr"
            level:    debug
            channels: ["!event"]
            formatter: app.line_formatter
            excluded_404s:
                - .*
        main:
            type:   stream
            path:   "%kernel.logs_dir%/%kernel.environment%.log"
            level:  debug
            formatter: app.line_formatter
            excluded_404s:
                - .*
        console:
            type:   console
            bubble: false
            verbosity_levels:
                VERBOSITY_VERBOSE: INFO
                VERBOSITY_VERY_VERBOSE: DEBUG
        console_very_verbose:
            type:   console
            bubble: false
            verbosity_levels:
                VERBOSITY_VERBOSE: NOTICE
                VERBOSITY_VERY_VERBOSE: NOTICE
                VERBOSITY_DEBUG: DEBUG

config_prod.yml

monolog:
    handlers:
        app:
            type:     stream
            level:    debug
            channels: ["!event", "!request", "!security"]
            excluded_404s:
                - .*
            handler: awslogs

        main:
            type:   stream
            level:  debug
            formatter: app.line_formatter
            excluded_404s:
                - .*
            handler: awslogs

        awslogs:
            type: service
            id: cloudwatch_handler

services.yml

    cloudwatch_client:
        class: Aws\CloudWatchLogs\CloudWatchLogsClient
        arguments:
            -
                credentials: false
                region: "eu-west-1"
                version: "2014-03-28"

    cloudwatch_handler:
        class: Maxbanton\Cwh\Handler\CloudWatch
        arguments:
            - "@cloudwatch_client"
            - "symfony"              # groupName
            - "%kernel.environment%" # streamName
            - 15                     # retentionDays
            - 10000                  # logsInBatch
            - { mytag: "tag" }       # tags