Rationale

• The Java logging ecosystem is a broken plate that's been haphazardly glued back together.
• The community is beginning to realize there's great value in logging structured data, not text.
• It's far from feasible to move the Java ecosystem towards a new standard.
• Containers have replaced application servers and aggregating logs has become an infrastructure service.
• clojure.tools.logging routes your clojure logging right through the mess instead of around it.
• timbre is a macro-laden kitchen sink that you have to configure at runtime.

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Resolution

I offer a new logging library for Clojure applications. It is opinionated and restrained.

• It will route all java logging libraries through itself without requiring any configuration.
• It will only support output as structured data, serialized as json.
• It will perform all masking / serializing / output on a background thread.
• It will not support runtime configuration and instead use an edn config file on the classpath.
• It will not support pluggable appenders and will only ever write to standard out and standard error.
• It will provide excellent test facilities for asserting log statements made in your code.
• It will offer good, though perhaps not great, performance.
• It will bypass any and all java logging libraries when you log from Clojure.
• It will include any available MDC data in the logs.
• It will provide stack-based logging contexts for Clojure that support rich data (not only key/value strings like MDC).
• It will support filtering for accidental sensitive data.
• It will namespace attributes to ensure consistent data types for a given key (important if you're later ingesting into elasticsearch).
• It will accept your arguments in any order because who can remember that.
• It will use a simple string template language that support accessing values in structured data.
• It will allow you to provide delayed values for things you don't want to compute unless a log level is enabled.

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License

This project is licensed under MIT license.