Add custom soci-snapshotter User-Agent when fetching spans

Signed-off-by: Yasin Turan <turyasin@amazon.com>

Author: turan18

fs/remote/resolver.go

@@ -429,6 +429,7 @@ func (f *httpFetcher) fetch(ctx context.Context, rs []region, retry bool) (multi
 	}
 	req.Header.Add("Range", fmt.Sprintf("bytes=%s", ranges[:len(ranges)-1]))
 	req.Header.Add("Accept-Encoding", "identity")
+	req.Header.Add("User-Agent", socihttp.UserAgent)
 	req.Close = false
 
 	// Recording the roundtrip latency for remote registry GET operation.

fs/remote/resolver_test.go

@@ -296,7 +296,7 @@ func TestRetry(t *testing.T) {
 	}
 
 	if tr.retryCount != 4 {
-		t.Fatalf("unxpected retryCount; expected=4 got=%d", tr.retryCount)
+		t.Fatalf("unexpected retryCount; expected=4 got=%d", tr.retryCount)
 	}
 }
 
@@ -335,3 +335,37 @@ func (r *retryRoundTripper) RoundTrip(req *http.Request) (res *http.Response, er
 	}
 	return
 }
+
+func TestCustomUserAgent(t *testing.T) {
+	rt := &userAgentRoundTripper{expectedUserAgent: socihttp.UserAgent}
+	f := &httpFetcher{
+		url: "dummyregistry",
+		tr:  rt,
+	}
+	regions := []region{{b: 0, e: 1}}
+	_, err := f.fetch(context.Background(), regions, true)
+	if err != nil {
+		t.Fatalf("unexpected error = %v", err)
+	}
+	if rt.roundTripUserAgent != rt.expectedUserAgent {
+		t.Fatalf("unexpected User-Agent; expected %s; got %s", rt.expectedUserAgent, rt.roundTripUserAgent)
+	}
+}
+
+type userAgentRoundTripper struct {
+	expectedUserAgent  string
+	roundTripUserAgent string
+}
+
+func (u *userAgentRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	u.roundTripUserAgent = req.UserAgent()
+
+	header := make(http.Header)
+	header.Add("Content-Length", "4")
+	return &http.Response{
+		StatusCode: http.StatusOK,
+		Request:    req,
+		Header:     header,
+		Body:       io.NopCloser(bytes.NewReader([]byte("test"))),
+	}, nil
+}

util/http/retry.go

@@ -18,17 +18,23 @@ package http
 
 import (
 	"context"
+	"fmt"
 	"math/rand"
 	"net"
 	"net/http"
 	"time"
 
 	"github.com/awslabs/soci-snapshotter/config"
+	"github.com/awslabs/soci-snapshotter/version"
 	"github.com/containerd/containerd/log"
 	rhttp "github.com/hashicorp/go-retryablehttp"
 	"github.com/sirupsen/logrus"
 )
 
+var (
+	UserAgent = fmt.Sprintf("soci-snapshotter/%s", version.Version)
+)
+
 // NewRetryableClient creates a go http.Client which will automatically
 // retry on non-fatal errors
 func NewRetryableClient(config config.RetryableHTTPClientConfig) *http.Client {