1 files changed, 63 insertions, 0 deletions
diff --git a/go/vendor/gitlab.com/gitlab-org/labkit/tracing/env_extractor.go b/go/vendor/gitlab.com/gitlab-org/labkit/tracing/env_extractor.go
new file mode 100644
index 0000000..2b92a8a
--- /dev/null
+++ b/go/vendor/gitlab.com/gitlab-org/labkit/tracing/env_extractor.go
@@ -0,0 +1,63 @@
+package tracing
+
+import (
+	"context"
+	"os"
+	"strings"
+
+	opentracing "github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go/ext"
+	"gitlab.com/gitlab-org/labkit/correlation"
+)
+
+// ExtractFromEnv will extract a span from the environment after it has been passed in
+// from the parent process. Returns a new context, and a defer'able function, which
+// should be called on process termination
+func ExtractFromEnv(ctx context.Context, opts ...ExtractFromEnvOption) (context.Context, func()) {
+	/* config not yet used */ applyExtractFromEnvOptions(opts)
+	tracer := opentracing.GlobalTracer()
+
+	// Extract the Correlation-ID
+	envMap := environAsMap(os.Environ())
+	correlationID := envMap[envCorrelationIDKey]
+	if correlationID != "" {
+		ctx = correlation.ContextWithCorrelation(ctx, correlationID)
+	}
+
+	// Attempt to deserialize tracing identifiers
+	wireContext, err := tracer.Extract(
+		opentracing.TextMap,
+		opentracing.TextMapCarrier(envMap))
+
+	if err != nil {
+		/* Clients could send bad data, in which case we simply ignore it */
+		return ctx, func() {}
+	}
+
+	// Create the span referring to the RPC client if available.
+	// If wireContext == nil, a root span will be created.
+	additionalStartSpanOpts := []opentracing.StartSpanOption{
+		ext.RPCServerOption(wireContext),
+	}
+
+	if correlationID != "" {
+		additionalStartSpanOpts = append(additionalStartSpanOpts, opentracing.Tag{Key: "correlation_id", Value: correlationID})
+	}
+
+	serverSpan := opentracing.StartSpan(
+		"execute",
+		additionalStartSpanOpts...,
+	)
+	ctx = opentracing.ContextWithSpan(ctx, serverSpan)
+
+	return ctx, func() { serverSpan.Finish() }
+}
+
+func environAsMap(env []string) map[string]string {
+	envMap := make(map[string]string, len(env))
+	for _, v := range env {
+		s := strings.SplitN(v, "=", 2)
+		envMap[s[0]] = s[1]
+	}
+	return envMap
+}