update to go.opentelemetry.io/otel/semconv/v1.21.0, remove "httpconv" uses

This commit switches our code to use semconv 1.21, which is the version matching
the OTEL modules, as well as the containerd code.

The BuildKit 0.12.x module currently uses an older version of the OTEL modules,
and uses the semconv 0.17 schema. Mixing schema-versions is problematic, but
we still want to consume BuildKit's "detect" package to wire-up other parts
of OTEL.

To align the versions in our code, this patch sets the BuildKit detect.Resource
with the correct semconv version.

It's worth noting that the BuildKit package has a custom "serviceNameDetector";
https://github.com/moby/buildkit/blob/v0.12.4/util/tracing/detect/detect.go#L153-L169

Whith is merged with OTEL's default resource:
https://github.com/moby/buildkit/blob/v0.12.4/util/tracing/detect/detect.go#L100-L107

There's no need to duplicate that code, as OTEL's `resource.Default()` already
provides this functionality:

- It uses fromEnv{} detector internally: https://github.com/open-telemetry/opentelemetry-go/blob/v1.19.0/sdk/resource/resource.go#L208
- fromEnv{} detector reads OTEL_SERVICE_NAME: https://github.com/open-telemetry/opentelemetry-go/blob/v1.19.0/sdk/resource/env.go#L53

This patch also removes uses of the httpconv package, which is no longer included
in semconv 1.21 and now an internal package. Removing the use of this package
means that hijacked connections will not have the HTTP attributes on the Moby
client span, which isn't ideal, but a limited loss that'd impact exec/attach.
The span itself will still exist, it just won't the additional attributes that
are added by that package.

Alternatively, the httpconv call COULD remain - it will not error and will send
syntactically valid spans but we would be mixing & matching semconv versions,
so won't be compliant.

Some parts of the httpconv package were preserved through a very minimal local
implementation; a variant of `httpconv.ClientStatus(resp.StatusCode))` is added
to set the span status (`span.SetStatus()`). The `httpconv` package has complex
logic for this, but mostly drills down to HTTP status range (1xx/2xx/3xx/4xx/5xx)
to determine if the status was successfull or non-successful (4xx/5xx).

The additional logic it provided was to validate actual status-codes, and to
convert "bogus" status codes in "success" ranges (1xx, 2xx) into an error. That
code seemed over-reaching (and not accounting for potential future _valid_
status codes). Let's assume we only get valid status codes.

- https://github.com/open-telemetry/opentelemetry-go/blob/v1.21.0/semconv/v1.17.0/httpconv/http.go#L85-L89
- https://github.com/open-telemetry/opentelemetry-go/blob/v1.21.0/semconv/internal/v2/http.go#L322-L330
- https://github.com/open-telemetry/opentelemetry-go/blob/v1.21.0/semconv/internal/v2/http.go#L356-L404

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

client/hijack.go

@@ -16,7 +16,6 @@ import (
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/codes"
 	"go.opentelemetry.io/otel/propagation"
-	"go.opentelemetry.io/otel/semconv/v1.17.0/httpconv"
 	"go.opentelemetry.io/otel/trace"
 )
 
@@ -66,7 +65,8 @@ func (cli *Client) setupHijackConn(req *http.Request, proto string) (_ net.Conn,
 	}
 
 	ctx, span := tp.Tracer("").Start(ctx, req.Method+" "+req.URL.Path, trace.WithSpanKind(trace.SpanKindClient))
-	span.SetAttributes(httpconv.ClientRequest(req)...)
+	// FIXME(thaJeztah): httpconv.ClientRequest is now an internal package; replace this with alternative for semconv v1.21
+	// span.SetAttributes(httpconv.ClientRequest(req)...)
 	defer func() {
 		if retErr != nil {
 			span.RecordError(retErr)
@@ -98,7 +98,27 @@ func (cli *Client) setupHijackConn(req *http.Request, proto string) (_ net.Conn,
 	// Server hijacks the connection, error 'connection closed' expected
 	resp, err := clientconn.Do(req)
 	if resp != nil {
-		span.SetStatus(httpconv.ClientStatus(resp.StatusCode))
+		// This is a simplified variant of "httpconv.ClientStatus(resp.StatusCode))";
+		//
+		// The main purpose of httpconv.ClientStatus() is to detect whether the
+		// status was successful (1xx, 2xx, 3xx) or non-successful (4xx/5xx).
+		//
+		// It also provides complex logic to *validate* status-codes against
+		// a hard-coded list meant to exclude "bogus" status codes in "success"
+		// ranges (1xx, 2xx) and convert them into an error status. That code
+		// seemed over-reaching (and not accounting for potential future valid
+		// status codes). We assume we only get valid status codes, and only
+		// look at status-code ranges.
+		//
+		// For reference, see:
+		// https://github.com/open-telemetry/opentelemetry-go/blob/v1.21.0/semconv/v1.17.0/httpconv/http.go#L85-L89
+		// https://github.com/open-telemetry/opentelemetry-go/blob/v1.21.0/semconv/internal/v2/http.go#L322-L330
+		// https://github.com/open-telemetry/opentelemetry-go/blob/v1.21.0/semconv/internal/v2/http.go#L356-L404
+		code := codes.Unset
+		if resp.StatusCode >= http.StatusBadRequest {
+			code = codes.Error
+		}
+		span.SetStatus(code, "")
 	}
 
 	//nolint:staticcheck // ignore SA1019 for connecting to old (pre go1.8) daemons

cmd/dockerd/daemon.go

@@ -63,6 +63,7 @@ import (
 	"github.com/spf13/pflag"
 	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/propagation"
+	"go.opentelemetry.io/otel/sdk/resource"
 	"tags.cncf.io/container-device-interface/pkg/cdi"
 )
 
@@ -238,6 +239,10 @@ func (cli *DaemonCli) start(opts *daemonOptions) (err error) {
 
 	setOTLPProtoDefault()
 	otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))
+
+	// Override BuildKit's default Resource so that it matches the semconv
+	// version that is used in our code.
+	detect.Resource = resource.Default()
 	detect.Recorder = detect.NewTraceRecorder()
 
 	tp, err := detect.TracerProvider()

testutil/helpers.go

@@ -16,7 +16,7 @@ import (
 	"go.opentelemetry.io/otel/propagation"
 	"go.opentelemetry.io/otel/sdk/resource"
 	"go.opentelemetry.io/otel/sdk/trace"
-	semconv "go.opentelemetry.io/otel/semconv/v1.17.0"
+	semconv "go.opentelemetry.io/otel/semconv/v1.21.0"
 	"gotest.tools/v3/icmd"
 )
 
@@ -34,7 +34,7 @@ func (d devZero) Read(p []byte) (n int, err error) {
 
 var tracingOnce sync.Once
 
-// configureTracing sets up an OTLP tracing exporter for use in tests.
+// ConfigureTracing sets up an OTLP tracing exporter for use in tests.
 func ConfigureTracing() func(context.Context) {
 	if os.Getenv("OTEL_EXPORTER_OTLP_ENDPOINT") == "" {
 		// No OTLP endpoint configured, so don't bother setting up tracing.
@@ -52,9 +52,7 @@ func ConfigureTracing() func(context.Context) {
 		tp = trace.NewTracerProvider(
 			trace.WithSpanProcessor(sp),
 			trace.WithSampler(trace.AlwaysSample()),
-			trace.WithResource(resource.NewSchemaless(
-				attribute.KeyValue{Key: semconv.ServiceNameKey, Value: attribute.StringValue("integration-test-client")},
-			)),
+			trace.WithResource(resource.NewSchemaless(semconv.ServiceName("integration-test-client"))),
 		)
 		otel.SetTracerProvider(tp)