Logging

PURISTA provides logging as integral part. Per default, pino is used under the hood as logging library.

This means, during development you are able to use pino-pretty for better human readable console log output.

But you can in theory use any logging library. There is only the need to build a simple wrapper. This wrapper should be a class which extends Logger from @purista/core. See DefaultLogger.ts in core package.

The logger is expected to log:

• serviceName
• serviceVersion
• serviceTarget (available logged in context of a command or subscription)
• principalId (if available)
• tenantId (if available)
• traceId (custom traceId)
• OpenTelemetry traces

When messages are logged - the message payload will be removed to prevent leaking of data.

To log errors with stacktrace correctly, you should log them as err.

logger.error({ err }, 'my own error message')

You should not use traceId, spanId, parentId, parentSpanId, traceFlags or principalId as property of the logging object. This might overwrite automatically added log information.

Available log levels are info, fatal, error, warn, debug and trace.

Internally, PURISTA tries to cover these use cases with different log levels:

• info = general information like used port, service status and so on
• fatal = if a service is unable to start at all
• error = if some unexpected/unhandled error occurs like a command function is throwing
• warning = if for example a http request fails because of input validation
• debug = general framework flow information which should not be logged in production
• trace = detailed raw data mainly of third party plugins

In production, log level warn is recommended.

INFO

Service instances will create a own logger