VictoriaMetrics/lib/protoparser/opentelemetry/firehose/parser.go
2024-03-26 13:20:41 +01:00

67 lines
1.9 KiB
Go

package firehose
import (
"encoding/binary"
"encoding/json"
"fmt"
"net/http"
"time"
)
// ProcessRequestBody converts Cloudwatch Stream protobuf metrics HTTP request body delivered via Firehose into OpenTelemetry protobuf message.
//
// See https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch-Metric-Streams.html
//
// It joins decoded "data" fields from "record" list:
//
// {
// "requestId": "<uuid-string>",
// "timestamp": <int64-value>,
// "records": [
// {
// "data": "<base64-encoded-payload>"
// }
// ]
// }
func ProcessRequestBody(b []byte) ([]byte, error) {
var req struct {
Records []struct {
Data []byte
}
}
if err := json.Unmarshal(b, &req); err != nil {
return nil, fmt.Errorf("cannot unmarshal Firehose JSON in request body: %s", err)
}
var dst []byte
for _, r := range req.Records {
for len(r.Data) > 0 {
messageLength, varIntLength := binary.Uvarint(r.Data)
if varIntLength > binary.MaxVarintLen32 {
return nil, fmt.Errorf("failed to parse OpenTelemetry message: invalid variant")
}
totalLength := varIntLength + int(messageLength)
if totalLength > len(r.Data) {
return nil, fmt.Errorf("failed to parse OpenTelementry message: insufficient length of buffer")
}
dst = append(dst, r.Data[varIntLength:totalLength]...)
r.Data = r.Data[totalLength:]
}
}
return dst, nil
}
// ResponseWriter writes response for AWS Firehose HTTP Endpoint request
// https://docs.aws.amazon.com/firehose/latest/dev/httpdeliveryrequestresponse.html#responseformat
func ResponseWriter(w http.ResponseWriter, ct time.Time, reqID string, err error) {
var respBody string
ts := ct.UnixMilli()
if err == nil {
respBody = fmt.Sprintf(`{"requestId": %q,"timestamp": %d}`, reqID, ts)
} else {
respBody = fmt.Sprintf(`{"requestId": %q,"timestamp": %d,"errorMessage": %q}`, reqID, ts, err)
}
w.Header().Add("Content-Type", "application/json")
w.Write([]byte(respBody))
}