Add disable_keep_alives configuration option to Zipkin receiver

.chloggen/feat_zipkin-receiver-disable-keep-alives.yaml

@@ -0,0 +1,31 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# 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: Add `disable_keep_alives` configuration option to control HTTP keep-alive behavior
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [42531]
+
+# (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: |
+  This allows users to disable HTTP keep-alive connections in the Zipkin receiver.
+  When disabled, the server will close connections after each request, which can
+  help with resource management in high-load scenarios or when working with certain
+  load balancers. The feature is disabled by default to maintain backward compatibility.
+
+# 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: [user]

receiver/zipkinreceiver/README.md

@@ -27,10 +27,19 @@ receivers:
   zipkin:
 ```
 
+To disable HTTP keep-alive connections:
+
+```yaml
+receivers:
+  zipkin:
+    disable_keep_alives: true
+```
+
 The following settings are configurable:
 
 - `endpoint` (default = localhost:9411): host:port on which the receiver is going to receive data.See our [security best practices doc](https://opentelemetry.io/docs/security/config-best-practices/#protect-against-denial-of-service-attacks) to understand how to set the endpoint in different environments.  You can review the [full list of `ServerConfig`](https://github.com/open-telemetry/opentelemetry-collector/tree/main/config/confighttp).
 - `parse_string_tags` (default = false): if enabled, the receiver will attempt to parse string tags/binary annotations into int/bool/float.
+- `disable_keep_alives` (default = false): if true, HTTP keep-alive is disabled. When disabled, the server will close connections after each request.
 
 ## Advanced Configuration
 

receiver/zipkinreceiver/config.go

@@ -15,6 +15,8 @@ type Config struct {
 	// If enabled the zipkin receiver will attempt to parse string tags/binary annotations into int/bool/float.
 	// Disabled by default
 	ParseStringTags bool `mapstructure:"parse_string_tags"`
+	// If true, HTTP keep-alive is disabled. By default, keep-alive is enabled.
+	DisableKeepAlives bool `mapstructure:"disable_keep_alives"`
 
 	// prevent unkeyed literal initialization
 	_ struct{}

receiver/zipkinreceiver/config_test.go

@@ -49,6 +49,15 @@ func TestLoadConfig(t *testing.T) {
 				ParseStringTags: true,
 			},
 		},
+		{
+			id: component.NewIDWithName(metadata.Type, "disable_keep_alives"),
+			expected: &Config{
+				ServerConfig: confighttp.ServerConfig{
+					Endpoint: defaultHTTPEndpoint,
+				},
+				DisableKeepAlives: true,
+			},
+		},
 	}
 
 	for _, tt := range tests {

receiver/zipkinreceiver/testdata/config.yaml

@@ -3,3 +3,5 @@ zipkin/customname:
   endpoint: "localhost:8765"
 zipkin/parse_strings:
   parse_string_tags: true
+zipkin/disable_keep_alives:
+  disable_keep_alives: true

receiver/zipkinreceiver/trace_receiver.go

@@ -100,6 +100,11 @@ func (zr *zipkinReceiver) Start(ctx context.Context, host component.Host) error
 		return err
 	}
 
+	// Apply keep-alive setting to the HTTP server
+	if zr.config.DisableKeepAlives {
+		zr.server.SetKeepAlivesEnabled(false)
+	}
+
 	var listener net.Listener
 	listener, err = zr.config.ToListener(ctx)
 	if err != nil {

receiver/zipkinreceiver/trace_receiver_test.go

@@ -496,3 +496,57 @@ func TestFromBytesWithNoTimestamp(t *testing.T) {
 	assert.True(t, mapContainedKey)
 	assert.True(t, wasAbsent.Bool())
 }
+
+func TestKeepAliveConfig(t *testing.T) {
+	tests := []struct {
+		name              string
+		disableKeepAlives bool
+		expectedEnabled   bool
+	}{
+		{
+			name:              "keep-alive enabled by default",
+			disableKeepAlives: false,
+			expectedEnabled:   true,
+		},
+		{
+			name:              "keep-alive disabled when configured",
+			disableKeepAlives: true,
+			expectedEnabled:   false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			// Get a random port for testing
+			listener, err := net.Listen("tcp", "localhost:0")
+			require.NoError(t, err)
+			addr := listener.Addr().String()
+			require.NoError(t, listener.Close())
+
+			cfg := &Config{
+				ServerConfig: confighttp.ServerConfig{
+					Endpoint: addr,
+				},
+				DisableKeepAlives: tt.disableKeepAlives,
+			}
+
+			sink := &consumertest.TracesSink{}
+			r, err := newReceiver(cfg, sink, receivertest.NewNopSettings(metadata.Type))
+			require.NoError(t, err)
+
+			require.NoError(t, r.Start(t.Context(), componenttest.NewNopHost()))
+			t.Cleanup(func() {
+				require.NoError(t, r.Shutdown(t.Context()))
+			})
+
+			// Make a request to verify the server starts successfully
+			body := `[{"traceId":"1","id":"2","name":"test","timestamp":1234567890123456,"duration":1000000}]`
+			resp, err := http.Post(fmt.Sprintf("http://%s/api/v2/spans", addr), "application/json", bytes.NewBufferString(body))
+			require.NoError(t, err)
+			defer resp.Body.Close()
+			assert.Equal(t, http.StatusAccepted, resp.StatusCode)
+			assert.NotNil(t, r.server, "HTTP server should be initialized")
+			assert.Equal(t, tt.disableKeepAlives, cfg.DisableKeepAlives, "Configuration should match expected value")
+		})
+	}
+}