add utility to inspect gzip'ed payload

cmd/otelq/README.md

@@ -1,3 +0,0 @@
-# Otelq
-
-Like `jq` or `yq`, but for OpenTelemetry data.

cmd/otelq/main.go

@@ -1,48 +0,0 @@
-package main
-
-import (
-	"flag"
-	"fmt"
-	"io"
-	"log"
-	"os"
-
-	tracev1 "go.opentelemetry.io/proto/otlp/trace/v1"
-	"google.golang.org/protobuf/encoding/protojson"
-	"google.golang.org/protobuf/proto"
-)
-
-var (
-	file = flag.String("file", "", "OpenTelemetry proto file. if set, will not use stdin.")
-)
-
-func main() {
-	flag.Parse()
-
-	if *file != "" {
-		fmt.Fprintf(os.Stderr, "reading file %s\n", *file)
-		h := must(os.Open(*file))
-		bs := must(io.ReadAll(h))
-
-		var td tracev1.TracesData
-		if err := proto.Unmarshal(bs, &td); err != nil {
-			log.Fatalln(err)
-		}
-
-		jsonbs, err := protojson.Marshal(&td)
-		if err != nil {
-			log.Fatalln(err)
-		}
-
-		fmt.Fprint(os.Stdout, string(jsonbs))
-	} else {
-		fmt.Println("using stdin")
-	}
-}
-
-func must[T any](v T, err error) T {
-	if err != nil {
-		log.Fatalln(err)
-	}
-	return v
-}

go.mod

@@ -3,7 +3,6 @@ module go.wperron.io/toolkit
 go 1.20
 
 require (
-	github.com/golang/protobuf v1.5.2
 	github.com/grafana/tempo v1.5.0
 	github.com/stretchr/testify v1.8.4
 	go.opentelemetry.io/otel/sdk v1.14.0
@@ -15,6 +14,7 @@ require (
 	github.com/cenkalti/backoff/v4 v4.2.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
 	github.com/grpc-ecosystem/grpc-gateway/v2 v2.7.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	go.opentelemetry.io/otel/exporters/otlp/internal/retry v1.14.0 // indirect

gziputil/util.go

@@ -0,0 +1,59 @@
+package gziputil
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+type Gzip struct {
+	magic []byte
+	cm    byte
+	flg   byte
+	mtime uint32
+	xfl   byte
+	os    byte
+	xlen  uint16
+	xflds []byte
+	crc32 uint32
+	isize uint32
+
+	rest    []byte
+	trailer []byte
+}
+
+func explainGzip(bs []byte) Gzip {
+	g := Gzip{
+		magic: bs[0:2],
+		cm:    bs[2],
+		flg:   bs[3],
+		mtime: binary.BigEndian.Uint32(bs[4:8]),
+		xfl:   bs[8],
+		os:    bs[9],
+	}
+
+	offset := 10
+	if g.xfl&2 == 1 {
+		g.xlen = binary.BigEndian.Uint16(bs[offset : offset+2])
+		offset += 2
+
+		g.xflds = bs[offset : offset+int(g.xlen)]
+		offset += int(g.xlen)
+	}
+
+	g.crc32 = binary.BigEndian.Uint32(bs[offset : offset+4])
+	offset += 4
+
+	g.isize = binary.BigEndian.Uint32(bs[offset : offset+4])
+	offset += 4
+
+	g.rest = bs[offset : len(bs)-8]
+	offset = len(bs) - 8
+
+	g.trailer = bs[offset:]
+
+	return g
+}
+
+func (g Gzip) String() string {
+	return fmt.Sprintf("magic=%04x cm=%02x flg=%02x mtime=%d xfl=%02x os=%02x xlen=%d crc32=%d isize=%d rest=%x trailer=%08x", g.magic, g.cm, g.flg, g.mtime, g.xfl, g.os, g.xlen, g.crc32, g.isize, g.rest, g.trailer)
+}