[receiver/zipkin] follow receiver contract (open-telemetry#28627)

I came across `zipkinreceiver` and observed we don't
follow the receiver
[contract](https://github.com/open-telemetry/opentelemetry-collector/blob/b2961b799e2c1ec128f0539764af1fa10c839e04/receiver/doc.go#L21).
We return `InternalServerError` straight away without checking
permanent/non-permanent errors.

We should probably return BadRequest in case of permanent errors

open-telemetry/opentelemetry-collector#4335

**Testing:** Added test cases

Co-authored-by: Andrzej Stencel <[email protected]>

.chloggen/update-zipkin-permanent.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: zipkinreceiver
+
+# A brief description of the change. Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Return BadRequest in case of permanent errors
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [4335]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

receiver/zipkinreceiver/trace_receiver.go

@@ -16,6 +16,7 @@ import (
 
  "go.opentelemetry.io/collector/component"
  "go.opentelemetry.io/collector/consumer"
+ "go.opentelemetry.io/collector/consumer/consumererror"
  "go.opentelemetry.io/collector/pdata/ptrace"
  "go.opentelemetry.io/collector/receiver"
  "go.opentelemetry.io/collector/receiver/receiverhelper"
@@ -32,6 +33,7 @@ const (
 )
 
 var errNextConsumerRespBody = []byte(`"Internal Server Error"`)
+var errBadRequestRespBody = []byte(`"Bad Request"`)
 
 // zipkinReceiver type is used to handle spans received in the Zipkin format.
 type zipkinReceiver struct {
@@ -239,17 +241,22 @@ func (zr *zipkinReceiver) ServeHTTP(w http.ResponseWriter, r *http.Request) {
  receiverTagValue = zipkinV1TagValue
  }
  obsrecv.EndTracesOp(ctx, receiverTagValue, td.SpanCount(), consumerErr)
+ if consumerErr == nil {
+ // Send back the response "Accepted" as
+ // required at https://zipkin.io/zipkin-api/#/default/post_spans
+ w.WriteHeader(http.StatusAccepted)
+ return
+ }
 
- if consumerErr != nil {
+ if consumererror.IsPermanent(consumerErr) {
+ w.WriteHeader(http.StatusBadRequest)
+ _, _ = w.Write(errBadRequestRespBody)
+ } else {
  // Transient error, due to some internal condition.
  w.WriteHeader(http.StatusInternalServerError)
  _, _ = w.Write(errNextConsumerRespBody)
- return
  }
 
- // Finally send back the response "Accepted" as
- // required at https://zipkin.io/zipkin-api/#/default/post_spans
- w.WriteHeader(http.StatusAccepted)
 }
 
 func transportType(r *http.Request, asZipkinv1 bool) string {

receiver/zipkinreceiver/trace_receiver_test.go

@@ -25,6 +25,7 @@ import (
  "go.opentelemetry.io/collector/component/componenttest"
  "go.opentelemetry.io/collector/config/confighttp"
  "go.opentelemetry.io/collector/consumer"
+ "go.opentelemetry.io/collector/consumer/consumererror"
  "go.opentelemetry.io/collector/consumer/consumertest"
  "go.opentelemetry.io/collector/pdata/ptrace"
  "go.opentelemetry.io/collector/receiver/receivertest"
@@ -288,6 +289,28 @@ func TestReceiverConsumerError(t *testing.T) {
  require.Equal(t, "\"Internal Server Error\"", req.Body.String())
 }
 
+func TestReceiverConsumerPermanentError(t *testing.T) {
+ body, err := os.ReadFile(zipkinV2Single)
+ require.NoError(t, err)
+
+ r := httptest.NewRequest("POST", "/api/v2/spans", bytes.NewBuffer(body))
+ r.Header.Add("content-type", "application/json")
+
+ cfg := &Config{
+ HTTPServerSettings: confighttp.HTTPServerSettings{
+ Endpoint: "localhost:9411",
+ },
+ }
+ zr, err := newReceiver(cfg, consumertest.NewErr(consumererror.NewPermanent(errors.New("consumer error"))), receivertest.NewNopCreateSettings())
+ require.NoError(t, err)
+
+ req := httptest.NewRecorder()
+ zr.ServeHTTP(req, r)
+
+ require.Equal(t, 400, req.Code)
+ require.Equal(t, "\"Bad Request\"", req.Body.String())
+}
+
 func thriftExample() []byte {
  now := time.Now().Unix()
  zSpans := []*zipkincore.Span{