Dev json logs

[krezreb]

Description:

Modifies the LineMessageFormatter to support outputting of log messages as json (one json object per line). This has a number of benefits for observability:

• No more multiline logs
• Logs can now be parsed out of the box without having to write specific parsers
• End-Users' ability to poison logs is limited as all logs are properly escaped

Also adds support for customers to add custom json processing to each line (useful for example for adding APM trace and span ids in for Datadog Unified service tagging users)

Review

• Functional review done
• Potential edge cases thought about (behavior of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• Security review done
• Wording review done
• Code review done
• Tests were added if useful/possible
• Reviewed for breaking changes
• Developer changelog updated if needed
• Documentation added if needed
• Existing documentation updated if needed

Depends on plugin PR matomo-org/plugin-LogViewer#99

To test json_logs

1. Checkout the dev-json-logs branch on Matomo core
2. Modify config/config.ini.php set enable_json = true (see example below)

[log]
log_writers[] = file
log_level = DEBUG
enable_json = true
logger_file_path = tmp/logs/matomo.log

3. Tail the the log file and you should see the logs as json
4. Check the logviewer plugin index.php?module=LogViewer logs should appear correctly in the interface

To test exclude_pattens

1. Modify config/config.ini.php set one or more exclude_patterns, separated by pipes(see example below)

[log]
log_writers[] = file
log_level = DEBUG
exclude_patterns =  "Piwik\Plugin\Manager|Matomo is not set up"
enable_json = true
logger_file_path = tmp/logs/matomo.log

2. Tail the the log file and you should see the logs as json, EXCEPT FOR logs matching the exclude patterns

To test custom_function_file

1. Modify config/config.ini.php specify custom_function_file (see example below)

[log]
log_writers[] = file
log_level = DEBUG
custom_function_file = /var/www/html/config/custom.php
enable_json = true
logger_file_path = tmp/logs/matomo.log

2. Example custom.php

<?php

function userHandler(array $array) : ?array
{
        $array["foo"] = "bar";
        return $array;
};
# return a string matching the name of the above function
return 'userHandler';

2. Tail the the log file and you should see the logs as json with the above custom logic run, in the above case a key "foo" will be set to the value "bar"

[patrickli]

@krezreb please fix the PHPCS style check first. Referece: https://innocraft.atlassian.net/wiki/spaces/DE/pages/2395570181/Create+a+Github+action+to+check+if+code+formatting+is+as+per+PSR+standard