logruseq.go

package logruseq

import (
	"bytes"
	"fmt"
	"io/ioutil"
	"net/http"
	"time"

	"github.com/sirupsen/logrus"
)

// SeqHook sends logs to Seq via HTTP.
type SeqHook struct {
	endpoint string
	apiKey   string
	levels   []logrus.Level
}

// NewSeqHook creates a Seq hook for logrus which can send log events to the
// host specified, for example:
//     logruseq.NewSeqHook("http://localhost:5341")
// Optionally, the hook can be used with an API key, for example:
//     logruseq.NewSeqHook("http://localhost:5341",
//         logruseq.OptionAPIKey("N1ncujiT5pYGD6m4CF0"))
// Optionally, which levels to log can be specified:
//     logruseq.NewSeqHook("http://localhost:5341",
//         logruseq.OptionLevels([]logrus.Level{
//             logrus.WarnLevel,
//             logrus.ErrorLevel,
//             logrus.FatalLevel,
//             logrus.PanicLevel,
//         }))
func NewSeqHook(host string, opts ...func(*SeqHookOptions)) *SeqHook {
	sho := &SeqHookOptions{
		levels: []logrus.Level{
			logrus.TraceLevel,
			logrus.DebugLevel,
			logrus.InfoLevel,
			logrus.WarnLevel,
			logrus.ErrorLevel,
			logrus.FatalLevel,
			logrus.PanicLevel,
		},
	}

	for _, opt := range opts {
		opt(sho)
	}

	endpoint := fmt.Sprintf("%v/api/events/raw", host)

	return &SeqHook{
		endpoint: endpoint,
		apiKey:   sho.apiKey,
		levels:   sho.levels,
	}
}

// Fire sends a log entry to Seq.
func (hook *SeqHook) Fire(entry *logrus.Entry) error {
	formatter := logrus.JSONFormatter{
		TimestampFormat: time.RFC3339Nano,
		FieldMap: logrus.FieldMap{
			logrus.FieldKeyMsg:   "@mt",
			logrus.FieldKeyLevel: "@l",
			logrus.FieldKeyTime:  "@t",
		},
	}

	data, err := formatter.Format(entry)
	if err != nil {
		return err
	}

	req, err := http.NewRequest("POST", hook.endpoint, bytes.NewReader(data))
	if err != nil {
		return err
	}

	req.Header.Set("Content-Type", "application/vnd.serilog.clef")

	if hook.apiKey != "" {
		req.Header.Add("X-Seq-ApiKey", hook.apiKey)
	}

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusCreated {
		data, err = ioutil.ReadAll(resp.Body)
		if err != nil {
			return err
		}

		return fmt.Errorf("error creating seq event: %v", string(data))
	}

	return nil
}

// Levels returns the levels for which Fire will be called.
func (hook *SeqHook) Levels() []logrus.Level {
	return hook.levels
}

// SeqHookOptions collects non-default Seq hook options.
type SeqHookOptions struct {
	apiKey string
	levels []logrus.Level
}

// OptionAPIKey sets the Seq API key option.
func OptionAPIKey(apiKey string) func(opts *SeqHookOptions) {
	return func(opts *SeqHookOptions) {
		opts.apiKey = apiKey
	}
}

// OptionLevels sets the levels for which Fire will be called.
func OptionLevels(levels []logrus.Level) func(opts *SeqHookOptions) {
	return func(opts *SeqHookOptions) {
		opts.levels = levels
	}
}