Feature/json logging

[sigrdrifa]

This pull request introduces significant enhancements to logging functionality, including the addition of JSON-based logging for production environments, structured logging capabilities, and environment-specific log configurations. It also updates the application to use these new logging features throughout its lifecycle.

Logging Enhancements:

• Introduced a new LogFormat type to support both text-based and JSON-based logging formats, with JSON logging designed for production environments. (src/Logger.hs, src/Logger.hsR62-R142)
• Added helper functions (logInfoJSON, logErrorJSON, logDebugJSON) for structured JSON logging, enabling the inclusion of detailed metadata in log messages. (src/Logger.hs, src/Logger.hsR167-R184)
• Created a createLogEnv function to configure the logging environment based on the selected format. (src/Logger.hs, src/Logger.hsR62-R142)

Middleware and Application Logging:

• Implemented a new setJSONLogger middleware that logs HTTP requests and responses in JSON format, including metadata such as method, path, status code, and duration. (src/Config.hs, src/Config.hsL89-R138)
• Updated the initialize function to include JSON-based logging during application startup, configuration loading, and database migrations. (src/Init.hs, [1] [2]

Dependency Updates:

• Added aeson-pretty and http-types as new dependencies to support JSON logging and HTTP metadata handling. (hastl.cabal, hastl.cabalR43-R45)

[Copilot]

Pull Request Overview

This PR enhances the application’s logging by introducing a JSON logging format alongside the existing text format, adding structured logging helpers, and configuring environment-specific log behavior.

• Define LogFormat, createLogEnv, and a JSON scribe in Logger.hs
• Implement JSON-based HTTP request/response middleware in Config.hs and integrate JSON logging into initialization in Init.hs
• Update hastl.cabal with aeson-pretty and http-types dependencies

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
src/Logger.hs	Added LogFormat, JSON scribe, itemToJSON, and helpers
src/Init.hs	Use JSON logging during startup/migrations; env-based setup
src/Config.hs	Add setJSONLogger middleware for structured HTTP logging
hastl.cabal	Added aeson-pretty and http-types dependencies

Comments suppressed due to low confidence (1)

src/Logger.hs:178

• New JSON logging helpers (logInfoJSON, logErrorJSON, logDebugJSON) and the middleware lack accompanying unit or integration tests. Adding tests will ensure correct behavior and ease future refactoring.

logInfoJSON msg payload = logJSON mempty InfoS msg payload

[Copilot]

The comment above createLogEnvForEnvironment states Development should use text format, but the code sets Development to JSONFormat. Align the implementation with the comment or update the comment to match intended behavior.

Suggested change

	createLogEnvForEnvironment Development = createLogEnv JSONFormat
	createLogEnvForEnvironment Development = createLogEnv TextFormat

[Copilot]

This applies JSON logging in Development too, conflicting with the comment that JSON is only for production. Consider restricting JSON middleware to Production or update the comment accordingly.

Suggested change

	setJSONLogger Development env = katipLogger env
	setJSONLogger Development _ = id

[Copilot]

Flushing the logger set on every log event can become a performance bottleneck under high throughput. Consider using asynchronous or batched flushing.

Suggested change

	lockingAction <- FastLogger.newStdoutLoggerSet FastLogger.defaultBufSize >>= \loggerSet ->
	return $ \logStrData -> do
	FastLogger.pushLogStr loggerSet logStrData
	FastLogger.flushLogStr loggerSet
	loggerSet <- FastLogger.newStdoutLoggerSet FastLogger.defaultBufSize
	let lockingAction logStrData = FastLogger.pushLogStr loggerSet logStrData

[Copilot]

[nitpick] The manual string replacements to extract the log message are brittle and hard to read. Consider using a proper renderer or a dedicated function to convert LogStr to Text safely.

Suggested change

	, "message" .= (T.strip $ T.replace "LogStr {unLogStr = \"" "" $ T.replace "\"}" "" msgText)
	, "message" .= (T.strip $ logStrToText $ _itemMessage item)