brokeyourbike/nrlogrus

package nrlogrus

import (
    "fmt"
    "os"

    "github.com/newrelic/go-agent/v3/integrations/logcontext"
    "github.com/newrelic/go-agent/v3/newrelic"
    "github.com/sirupsen/logrus"
)

// ContextFormatter is a `logrus.Formatter` that will format logs for sending
// to New Relic.
type ContextFormatter struct {
    appName   string
    formatter logrus.Formatter
}

// NewFormatter creates a new `logrus.Formatter` that will format logs for
// sending to New Relic.
func NewFormatter(appName string, formatter logrus.Formatter) ContextFormatter {
    return ContextFormatter{
        appName:   appName,
        formatter: formatter,
    }
}

// NewFormatterFromEnvironment creates a new `logrus.Formatter` that will
// format logs for sending to New Relic.  The application name is read from
// the `NEW_RELIC_APP_NAME` environment variable.
func NewFormatterFromEnvironment(formatter logrus.Formatter) ContextFormatter {
    return NewFormatter(os.Getenv("NEW_RELIC_APP_NAME"), formatter)
}

// Format renders a single log entry.
func (f ContextFormatter) Format(e *logrus.Entry) ([]byte, error) {
    md := newrelic.LinkingMetadata{EntityName: f.appName, EntityType: "SERVICE"}

    if ctx := e.Context; nil != ctx {
        if trx := newrelic.FromContext(ctx); nil != trx {
            md = trx.GetLinkingMetadata()
        }
    }

    logcontext.AddLinkingMetadata(e.Data, md)

    e.Data[logcontext.KeyTimestamp] = uint64(e.Time.UnixNano()) / uint64(1000*1000)
    e.Data[logcontext.KeyMessage] = e.Message
    e.Data[logcontext.KeyLevel] = e.Level

    if e.HasCaller() {
        e.Data[logcontext.KeyFile] = e.Caller.File
        e.Data[logcontext.KeyLine] = e.Caller.Line
        e.Data[logcontext.KeyMethod] = e.Caller.Function
    }

    b, err := f.formatter.Format(e)
    if err != nil {
        return nil, fmt.Errorf("error formatting log entry: %w", err)
    }

    return b, nil
}