oc-lib/logs/lokiwriter.go

98 lines
2.1 KiB
Go

package logs
import (
"bytes"
"encoding/json"
"fmt"
"net/http"
"time"
)
type LokiWriter struct {
url string
labels map[string]string
httpClient *http.Client
}
type LokiPayload struct {
Streams []LokiStream `json:"streams"`
}
type LokiStream struct {
Stream map[string]string `json:"stream"`
Values [][]string `json:"values"`
}
func NewLokiWriter(url string, labels map[string]string) *LokiWriter {
return &LokiWriter{
url: url,
labels: labels,
httpClient: &http.Client{},
}
}
func (w *LokiWriter) Write(p []byte) (n int, err error) {
// Use zerolog to parse the log level
var event map[string]interface{}
if err := json.Unmarshal(p, &event); err != nil {
return 0, fmt.Errorf("failed to unmarshal log event: %w", err)
}
level := ""
if l, ok := event["level"].(string); ok {
level = l
}
message := ""
if m, ok := event["message"].(string); ok {
message = m
}
// Add log level to labels
labels := make(map[string]string)
for k, v := range w.labels {
labels[k] = v
}
labels["level"] = level
// Format the timestamp in nanoseconds
timestamp := fmt.Sprintf("%d000000", time.Now().UnixNano()/int64(time.Millisecond))
stream := LokiStream{
Stream: labels,
Values: [][]string{
{timestamp, message},
},
}
payload := LokiPayload{
Streams: []LokiStream{stream},
}
payloadBytes, err := json.Marshal(payload)
if err != nil {
return 0, fmt.Errorf("failed to marshal payload: %w", err)
}
//fmt.Printf("Sending payload to Loki: %s\n", string(payloadBytes))
req, err := http.NewRequest("POST", w.url + "/loki/api/v1/push", bytes.NewReader(payloadBytes))
if err != nil {
return 0, fmt.Errorf("failed to create HTTP request: %w", err)
}
req.Header.Set("Content-Type", "application/json")
resp, err := w.httpClient.Do(req)
if err != nil {
return 0, fmt.Errorf("failed to send log to Loki: %w", err)
}
defer resp.Body.Close()
//fmt.Printf("Loki response status: %d\n", resp.StatusCode)
if resp.StatusCode != http.StatusNoContent {
return 0, fmt.Errorf("received non-204 response from Loki: %d", resp.StatusCode)
}
return len(p), nil
}