tracing: New OpenTelemetry module (#4361)

* opentelemetry: create a new module

* fix imports

* fix test

* Update modules/caddyhttp/opentelemetry/README.md

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* Update modules/caddyhttp/opentelemetry/README.md

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* Update modules/caddyhttp/opentelemetry/README.md

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* Update modules/caddyhttp/opentelemetry/tracer.go

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* rename error ErrUnsupportedTracesProtocol

* replace spaces with tabs in the test data

* Update modules/caddyhttp/opentelemetry/README.md

Co-authored-by: Francis Lavoie <lavofr@gmail.com>

* Update modules/caddyhttp/opentelemetry/README.md

Co-authored-by: Francis Lavoie <lavofr@gmail.com>

* replace spaces with tabs in the README.md

* use default values for a propagation and exporter protocol

* set http attributes with helper

* simplify code

* Cleanup modules/caddyhttp/opentelemetry/README.md

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* Update link in README.md

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* Update documentation in README.md

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* Update link to naming spec in README.md

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* Rename module from opentelemetry to tracing

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* Rename span_name to span

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* Rename span_name to span

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* Simplify otel resource creation

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* handle extra attributes

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* update go.opentelemetry.io/otel/semconv to 1.7.0

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* update go.opentelemetry.io/otel version

* remove environment variable handling

* always use tracecontext,baggage as propagators

* extract tracer name into variable

* rename OpenTelemetry to Tracing

* simplify resource creation

* update go.mod

* rename package from opentelemetry to tracing

* cleanup tests

* update Caddyfile example in README.md

* update README.md

* fix test

* fix module name in README.md

* fix module name in README.md

* change names in README.md and tests

* order imports

* remove redundant tests

* Update documentation README.md

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* Fix grammar

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* Update comments

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* Update comments

Co-authored-by: Dave Henderson <dhenderson@gmail.com>

* update go.sum

* update go.sum

* Add otelhttp instrumentation, update OpenTelemetry libraries.

* Use otelhttp instrumentation for instrumenting HTTP requests.

This change uses context.WithValue to inject the next handler into the
request context via a "nextCall" carrier struct, and pass it on to a
standard Go HTTP handler returned by otelhttp.NewHandler. The
underlying handler will extract the next handler from the context,
call it and pass the returned error to the carrier struct.

* use zap.Error() for the error log

* remove README.md

* update dependencies

* clean up the code

* change comment

* move serveHTTP method from separate file

* add syntax to the UnmarshalCaddyfile comment

* go import the file

* admin: Write proper status on invalid requests (#4569) (fix #4561)

* update dependencies

Co-authored-by: Dave Henderson <dhenderson@gmail.com>
Co-authored-by: Francis Lavoie <lavofr@gmail.com>
Co-authored-by: Vibhav Pant <vibhavp@gmail.com>
Co-authored-by: Alok Naushad <alokme123@gmail.com>
Co-authored-by: Cedric Ziel <cedric@cedric-ziel.com>

1 files changed, 182 insertions, 0 deletions

diff --git a/modules/caddyhttp/tracing/module_test.go b/modules/caddyhttp/tracing/module_test.go
new file mode 100644
index 0000000..0fbc05b
--- /dev/null
+++ b/modules/caddyhttp/tracing/module_test.go
@@ -0,0 +1,182 @@
+package tracing
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/caddyserver/caddy/v2"
+	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
+	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
+)
+
+func TestTracing_UnmarshalCaddyfile(t *testing.T) {
+	tests := []struct {
+		name     string
+		spanName string
+		d        *caddyfile.Dispenser
+		wantErr  bool
+	}{
+		{
+			name:     "Full config",
+			spanName: "my-span",
+			d: caddyfile.NewTestDispenser(`
+tracing {
+	span my-span
+}`),
+			wantErr: false,
+		},
+		{
+			name:     "Only span name in the config",
+			spanName: "my-span",
+			d: caddyfile.NewTestDispenser(`
+tracing {
+	span my-span
+}`),
+			wantErr: false,
+		},
+		{
+			name: "Empty config",
+			d: caddyfile.NewTestDispenser(`
+tracing {
+}`),
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ot := &Tracing{}
+			if err := ot.UnmarshalCaddyfile(tt.d); (err != nil) != tt.wantErr {
+				t.Errorf("UnmarshalCaddyfile() error = %v, wantErrType %v", err, tt.wantErr)
+			}
+
+			if ot.SpanName != tt.spanName {
+				t.Errorf("UnmarshalCaddyfile() SpanName = %v, want SpanName %v", ot.SpanName, tt.spanName)
+			}
+		})
+	}
+}
+
+func TestTracing_UnmarshalCaddyfile_Error(t *testing.T) {
+	tests := []struct {
+		name    string
+		d       *caddyfile.Dispenser
+		wantErr bool
+	}{
+		{
+			name: "Unknown parameter",
+			d: caddyfile.NewTestDispenser(`
+		tracing {
+			foo bar
+		}`),
+			wantErr: true,
+		},
+		{
+			name: "Missed argument",
+			d: caddyfile.NewTestDispenser(`
+tracing {
+	span
+}`),
+			wantErr: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ot := &Tracing{}
+			if err := ot.UnmarshalCaddyfile(tt.d); (err != nil) != tt.wantErr {
+				t.Errorf("UnmarshalCaddyfile() error = %v, wantErrType %v", err, tt.wantErr)
+			}
+		})
+	}
+}
+
+func TestTracing_ServeHTTP_Propagation_Without_Initial_Headers(t *testing.T) {
+	ot := &Tracing{
+		SpanName: "mySpan",
+	}
+
+	req := httptest.NewRequest("GET", "https://example.com/foo", nil)
+	w := httptest.NewRecorder()
+
+	var handler caddyhttp.HandlerFunc = func(writer http.ResponseWriter, request *http.Request) error {
+		traceparent := request.Header.Get("Traceparent")
+		if traceparent == "" || strings.HasPrefix(traceparent, "00-00000000000000000000000000000000-0000000000000000") {
+			t.Errorf("Invalid traceparent: %v", traceparent)
+		}
+
+		return nil
+	}
+
+	ctx, cancel := caddy.NewContext(caddy.Context{Context: context.Background()})
+	defer cancel()
+
+	if err := ot.Provision(ctx); err != nil {
+		t.Errorf("Provision error: %v", err)
+		t.FailNow()
+	}
+
+	if err := ot.ServeHTTP(w, req, handler); err != nil {
+		t.Errorf("ServeHTTP error: %v", err)
+	}
+}
+
+func TestTracing_ServeHTTP_Propagation_With_Initial_Headers(t *testing.T) {
+	ot := &Tracing{
+		SpanName: "mySpan",
+	}
+
+	req := httptest.NewRequest("GET", "https://example.com/foo", nil)
+	req.Header.Set("traceparent", "00-11111111111111111111111111111111-1111111111111111-01")
+	w := httptest.NewRecorder()
+
+	var handler caddyhttp.HandlerFunc = func(writer http.ResponseWriter, request *http.Request) error {
+		traceparent := request.Header.Get("Traceparent")
+		if !strings.HasPrefix(traceparent, "00-11111111111111111111111111111111") {
+			t.Errorf("Invalid traceparent: %v", traceparent)
+		}
+
+		return nil
+	}
+
+	ctx, cancel := caddy.NewContext(caddy.Context{Context: context.Background()})
+	defer cancel()
+
+	if err := ot.Provision(ctx); err != nil {
+		t.Errorf("Provision error: %v", err)
+		t.FailNow()
+	}
+
+	if err := ot.ServeHTTP(w, req, handler); err != nil {
+		t.Errorf("ServeHTTP error: %v", err)
+	}
+}
+
+func TestTracing_ServeHTTP_Next_Error(t *testing.T) {
+	ot := &Tracing{
+		SpanName: "mySpan",
+	}
+
+	req := httptest.NewRequest("GET", "https://example.com/foo", nil)
+	w := httptest.NewRecorder()
+
+	expectErr := errors.New("test error")
+
+	var handler caddyhttp.HandlerFunc = func(writer http.ResponseWriter, request *http.Request) error {
+		return expectErr
+	}
+
+	ctx, cancel := caddy.NewContext(caddy.Context{Context: context.Background()})
+	defer cancel()
+
+	if err := ot.Provision(ctx); err != nil {
+		t.Errorf("Provision error: %v", err)
+		t.FailNow()
+	}
+
+	if err := ot.ServeHTTP(w, req, handler); err == nil || !errors.Is(err, expectErr) {
+		t.Errorf("expected error, got: %v", err)
+	}
+}