sentrywriter

Overview ¶

Package sentrywriter is a wrapper around the sentry-go package and implements the io.Writer interface. This allows us to send logs from zerolog (or some other logging package that accepts the io.Writer interface) and send them to Sentry (there is no dependency on zerolog in this package).

There is a mechanism in this package to filter json formatted logs (we normally only want to send errors to Sentry, rather than all logs). For example, let's say you supply the writer with a `LogLevel`:

errorLevel := sentrywriter.LogLevel{
	MatchingString:"error",
	SentryLevel: sentry.ErrorLevel,
}
writer := sentrywriter.New(errorLevel)

The `writer` now has filtering turned on and when it next receives a log, it json decodes it and checks the `"level"` field (you can change this default using the `WithLevelFieldName` method) matches `"error"`. If it matches then it sets the sentry level to `sentry.ErrorLevel` and sends the message to Sentry. Multiple `LogLevel`s can be supplied both at instantiation time and at a later point, for example:

errorLevel := sentrywriter.LogLevel{
	MatchingString: "error",
	SentryLevel: sentry.ErrorLevel,
}
fatalLevel := sentrywriter.LogLevel{
	MatchingString: "fatal",
	SentryLevel: sentry.FatalLevel,
}
writer := sentrywriter.New(errorLevel, fatalLevel)

warningLevel := sentrywriter.LogLevel{
	MatchingString: "warning",
	SentryLevel: sentry.WarningLevel,
}
writer.WithLogLevel(warningLevel)

If no `LogLevel`s are provided then filtering is not turned on.

Here is a typical example, using zerolog. It is important to defer the `sentryWriter.Flush` function because the messages are sent to Sentry asynchronously.

    package main

    import (
	    "github.com/getsentry/sentry-go"
	    "github.com/sumup/sentrywriter"
	    "github.com/rs/zerolog"
	    "github.com/rs/zerolog/log"
    )

    func main() {
	    errorLevel := sentrywriter.LogLevel{"error", sentry.LevelError}
	    sentryWriter, err := sentrywriter.New(errorLevel).WithUserID("userID").SetDSN("your-project-sentry-dsn")
	    if err != nil {
		    log.Error().Err(err).Str("dsn", "your-project-sentry-dsn").Msg("sentrywriter.SentryWriter.SetDSN")
		    return
	    }
	    defer sentryWriter.Flush()

	    consoleWriter := zerolog.ConsoleWriter{Out: os.Stdout}
	    log.Logger = log.Output(zerolog.MultiLevelWriter(consoleWriter, sentryWriter))
    }

More sentry options can be set by using the `SetClientOptions(sentry.ClientOptions)` method instead of the `SetDSN(string)` method. See https://godoc.org/github.com/getsentry/sentry-go#ClientOptions for full details on all the available options. Here is an example:

package main

import (
	"github.com/getsentry/sentry-go"
	"github.com/sumup/sentrywriter"
	"github.com/rs/zerolog"
	"github.com/rs/zerolog/log"
)

func main() {
	errorLevel := sentrywriter.LogLevel{"error", sentry.LevelError}
	options := sentry.ClientOptions{
		Dsn: "your-project-sentry-dsn",
		AttachStacktrace: true,
		Environment: "your-environment",
		Release: "the-version-of-this-release",
	}
	sentryWriter, err := sentrywriter.New(errorLevel).WithUserID("userID").SetClientOptions(options)
	if err != nil {
		log.Error().Err(err).Str("dsn", "your-project-sentry-dsn").Msg("sentrywriter.SentryWriter.SetDSN")
		return
	}
	defer sentryWriter.Flush(2 * time.Second)

	consoleWriter := zerolog.ConsoleWriter{Out: os.Stdout}
	log.Logger = log.Output(zerolog.MultiLevelWriter(consoleWriter, sentryWriter))
}

Also see `example/main.go`.