Girish Kumar | 93e9174 | 2020-07-27 16:43:19 +0000 | [diff] [blame] | 1 | package grpc_opentracing |
| 2 | |
| 3 | import ( |
| 4 | "strings" |
| 5 | |
| 6 | grpc_ctxtags "github.com/grpc-ecosystem/go-grpc-middleware/tags" |
| 7 | opentracing "github.com/opentracing/opentracing-go" |
| 8 | "google.golang.org/grpc/grpclog" |
| 9 | ) |
| 10 | |
| 11 | const ( |
| 12 | TagTraceId = "trace.traceid" |
| 13 | TagSpanId = "trace.spanid" |
| 14 | TagSampled = "trace.sampled" |
| 15 | jaegerNotSampledFlag = "0" |
| 16 | ) |
| 17 | |
| 18 | // injectOpentracingIdsToTags writes trace data to ctxtags. |
| 19 | // This is done in an incredibly hacky way, because the public-facing interface of opentracing doesn't give access to |
| 20 | // the TraceId and SpanId of the SpanContext. Only the Tracer's Inject/Extract methods know what these are. |
| 21 | // Most tracers have them encoded as keys with 'traceid' and 'spanid': |
| 22 | // https://github.com/openzipkin/zipkin-go-opentracing/blob/594640b9ef7e5c994e8d9499359d693c032d738c/propagation_ot.go#L29 |
| 23 | // https://github.com/opentracing/basictracer-go/blob/1b32af207119a14b1b231d451df3ed04a72efebf/propagation_ot.go#L26 |
| 24 | // Jaeger from Uber use one-key schema with next format '{trace-id}:{span-id}:{parent-span-id}:{flags}' |
| 25 | // https://www.jaegertracing.io/docs/client-libraries/#trace-span-identity |
| 26 | func injectOpentracingIdsToTags(span opentracing.Span, tags grpc_ctxtags.Tags) { |
| 27 | if err := span.Tracer().Inject(span.Context(), opentracing.HTTPHeaders, &tagsCarrier{tags}); err != nil { |
| 28 | grpclog.Infof("grpc_opentracing: failed extracting trace info into ctx %v", err) |
| 29 | } |
| 30 | } |
| 31 | |
| 32 | // tagsCarrier is a really hacky way of |
| 33 | type tagsCarrier struct { |
| 34 | grpc_ctxtags.Tags |
| 35 | } |
| 36 | |
| 37 | func (t *tagsCarrier) Set(key, val string) { |
| 38 | key = strings.ToLower(key) |
| 39 | if strings.Contains(key, "traceid") { |
| 40 | t.Tags.Set(TagTraceId, val) // this will most likely be base-16 (hex) encoded |
| 41 | } |
| 42 | |
| 43 | if strings.Contains(key, "spanid") && !strings.Contains(strings.ToLower(key), "parent") { |
| 44 | t.Tags.Set(TagSpanId, val) // this will most likely be base-16 (hex) encoded |
| 45 | } |
| 46 | |
| 47 | if strings.Contains(key, "sampled") { |
| 48 | switch val { |
| 49 | case "true", "false": |
| 50 | t.Tags.Set(TagSampled, val) |
| 51 | } |
| 52 | } |
| 53 | |
| 54 | if key == "uber-trace-id" { |
| 55 | parts := strings.Split(val, ":") |
| 56 | if len(parts) == 4 { |
| 57 | t.Tags.Set(TagTraceId, parts[0]) |
| 58 | t.Tags.Set(TagSpanId, parts[1]) |
| 59 | |
| 60 | if parts[3] != jaegerNotSampledFlag { |
| 61 | t.Tags.Set(TagSampled, "true") |
| 62 | } else { |
| 63 | t.Tags.Set(TagSampled, "false") |
| 64 | } |
| 65 | } |
| 66 | } |
| 67 | } |