38 lines
2.1 KiB
Markdown
38 lines
2.1 KiB
Markdown
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# Zerolog Lint
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This is a basic linter that checks for missing log event finishers. Finds errors like: `log.Error().Int64("userID": 5)` - missing the `Msg`/`Msgf` finishers.
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## Problem
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When using zerolog it's easy to forget to finish the log event chain by calling a finisher - the `Msg` or `Msgf` function that will schedule the event for writing. The problem with this is that it doesn't warn/panic during compilation and it's not easily found by grep or other general tools. It's even prominently mentioned in the project's readme, that:
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> It is very important to note that when using the **zerolog** chaining API, as shown above (`log.Info().Msg("hello world"`), the chain must have either the `Msg` or `Msgf` method call. If you forget to add either of these, the log will not occur and there is no compile time error to alert you of this.
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## Solution
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A basic linter like this one here that looks for method invocations on `zerolog.Event` can examine the last call in a method call chain and check if it is a finisher, thus pointing out these errors.
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## Usage
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Just compile this and then run it. Or just run it via `go run` command via something like `go run cmd/lint/lint.go`.
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The command accepts only one argument - the package to be inspected - and 4 optional flags, all of which can occur multiple times. The standard synopsis of the command is:
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`lint [-finisher value] [-ignoreFile value] [-ignorePkg value] [-ignorePkgRecursively value] package`
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#### Flags
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- finisher
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- specify which finishers to accept, defaults to `Msg` and `Msgf`
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- ignoreFile
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- which files to ignore, either by full path or by go path (package/file.go)
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- ignorePkg
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- do not inspect the specified package if found in the dependecy tree
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- ignorePkgRecursively
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- do not inspect the specified package or its subpackages if found in the dependency tree
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## Drawbacks
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As it is, linter can generate a false positives in a specific case. These false positives come from the fact that if you have a method that returns a `zerolog.Event` the linter will flag it because you are obviously not finishing the event. This will be solved in later release.
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