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|
package opencensus
import (
"context"
"net/http"
"go.opencensus.io/plugin/ochttp"
"go.opencensus.io/plugin/ochttp/propagation/b3"
"go.opencensus.io/trace"
kithttp "github.com/go-kit/kit/transport/http"
)
// HTTPClientTrace enables OpenCensus tracing of a Go kit HTTP transport client.
func HTTPClientTrace(options ...TracerOption) kithttp.ClientOption {
cfg := TracerOptions{}
for _, option := range options {
option(&cfg)
}
if !cfg.Public && cfg.HTTPPropagate == nil {
cfg.HTTPPropagate = &b3.HTTPFormat{}
}
clientBefore := kithttp.ClientBefore(
func(ctx context.Context, req *http.Request) context.Context {
var name string
if cfg.Name != "" {
name = cfg.Name
} else {
// OpenCensus states Path being default naming for a client span
name = req.Method + " " + req.URL.Path
}
ctx, span := trace.StartSpan(
ctx,
name,
trace.WithSampler(cfg.Sampler),
trace.WithSpanKind(trace.SpanKindClient),
)
span.AddAttributes(
trace.StringAttribute(ochttp.HostAttribute, req.URL.Host),
trace.StringAttribute(ochttp.MethodAttribute, req.Method),
trace.StringAttribute(ochttp.PathAttribute, req.URL.Path),
trace.StringAttribute(ochttp.UserAgentAttribute, req.UserAgent()),
)
if !cfg.Public {
cfg.HTTPPropagate.SpanContextToRequest(span.SpanContext(), req)
}
return ctx
},
)
clientAfter := kithttp.ClientAfter(
func(ctx context.Context, res *http.Response) context.Context {
if span := trace.FromContext(ctx); span != nil {
span.SetStatus(ochttp.TraceStatus(res.StatusCode, http.StatusText(res.StatusCode)))
span.AddAttributes(
trace.Int64Attribute(ochttp.StatusCodeAttribute, int64(res.StatusCode)),
)
}
return ctx
},
)
clientFinalizer := kithttp.ClientFinalizer(
func(ctx context.Context, err error) {
if span := trace.FromContext(ctx); span != nil {
if err != nil {
span.SetStatus(trace.Status{
Code: trace.StatusCodeUnknown,
Message: err.Error(),
})
}
span.End()
}
},
)
return func(c *kithttp.Client) {
clientBefore(c)
clientAfter(c)
clientFinalizer(c)
}
}
// HTTPServerTrace enables OpenCensus tracing of a Go kit HTTP transport server.
func HTTPServerTrace(options ...TracerOption) kithttp.ServerOption {
cfg := TracerOptions{}
for _, option := range options {
option(&cfg)
}
if !cfg.Public && cfg.HTTPPropagate == nil {
cfg.HTTPPropagate = &b3.HTTPFormat{}
}
serverBefore := kithttp.ServerBefore(
func(ctx context.Context, req *http.Request) context.Context {
var (
spanContext trace.SpanContext
span *trace.Span
name string
ok bool
)
if cfg.Name != "" {
name = cfg.Name
} else {
name = req.Method + " " + req.URL.Path
}
spanContext, ok = cfg.HTTPPropagate.SpanContextFromRequest(req)
if ok && !cfg.Public {
ctx, span = trace.StartSpanWithRemoteParent(
ctx,
name,
spanContext,
trace.WithSpanKind(trace.SpanKindServer),
trace.WithSampler(cfg.Sampler),
)
} else {
ctx, span = trace.StartSpan(
ctx,
name,
trace.WithSpanKind(trace.SpanKindServer),
trace.WithSampler(cfg.Sampler),
)
if ok {
span.AddLink(trace.Link{
TraceID: spanContext.TraceID,
SpanID: spanContext.SpanID,
Type: trace.LinkTypeChild,
Attributes: nil,
})
}
}
span.AddAttributes(
trace.StringAttribute(ochttp.MethodAttribute, req.Method),
trace.StringAttribute(ochttp.PathAttribute, req.URL.Path),
)
return ctx
},
)
serverFinalizer := kithttp.ServerFinalizer(
func(ctx context.Context, code int, r *http.Request) {
if span := trace.FromContext(ctx); span != nil {
span.SetStatus(ochttp.TraceStatus(code, http.StatusText(code)))
if rs, ok := ctx.Value(kithttp.ContextKeyResponseSize).(int64); ok {
span.AddAttributes(
trace.Int64Attribute("http.response_size", rs),
)
}
span.End()
}
},
)
return func(s *kithttp.Server) {
serverBefore(s)
serverFinalizer(s)
}
}
|
