otelconf: add support for parsing resource detectors

otelconf/config_json.go

@@ -122,6 +122,56 @@ func (j *TraceContextPropagator) UnmarshalJSON(b []byte) error {
 	return nil
 }
 
+// UnmarshalJSON implements json.Unmarshaler.
+func (j *ExperimentalResourceDetector) UnmarshalJSON(b []byte) error {
+	// Use a shadow struct with a RawMessage field to detect key presence.
+	type Plain ExperimentalResourceDetector
+	type shadow struct {
+		Plain
+		Container json.RawMessage `json:"container"`
+		Host      json.RawMessage `json:"host"`
+		Process   json.RawMessage `json:"process"`
+		Service   json.RawMessage `json:"service"`
+	}
+	var sh shadow
+	if err := json.Unmarshal(b, &sh); err != nil {
+		return errors.Join(newErrUnmarshal(j), err)
+	}
+
+	if sh.Container != nil {
+		var c ExperimentalContainerResourceDetector
+		if err := json.Unmarshal(sh.Container, &c); err != nil {
+			return err
+		}
+		sh.Plain.Container = c
+	}
+
+	if sh.Host != nil {
+		var c ExperimentalHostResourceDetector
+		if err := json.Unmarshal(sh.Host, &c); err != nil {
+			return err
+		}
+		sh.Plain.Host = c
+	}
+
+	if sh.Process != nil {
+		var c ExperimentalProcessResourceDetector
+		if err := json.Unmarshal(sh.Process, &c); err != nil {
+			return err
+		}
+		sh.Plain.Process = c
+	}
+
+	if sh.Service != nil {
+		var c ExperimentalServiceResourceDetector
+		if err := json.Unmarshal(sh.Service, &c); err != nil {
+			return err
+		}
+		sh.Plain.Service = c
+	}
+	return nil
+}
+
 // UnmarshalJSON implements json.Unmarshaler.
 func (j *PushMetricExporter) UnmarshalJSON(b []byte) error {
 	// Use a shadow struct with a RawMessage field to detect key presence.

otelconf/config_test.go

@@ -828,9 +828,12 @@ var v10OpenTelemetryConfig = OpenTelemetryConfiguration{
 				Excluded: []string{"process.command_args"},
 				Included: []string{"process.*"},
 			},
-			// TODO: implement resource detectors https://github.com/open-telemetry/opentelemetry-go-contrib/issues/7252
-			// Detectors: []ExperimentalResourceDetector{}
-			// },
+			Detectors: []ExperimentalResourceDetector{
+				{Container: ExperimentalContainerResourceDetector{}},
+				{Host: ExperimentalHostResourceDetector{}},
+				{Process: ExperimentalProcessResourceDetector{}},
+				{Service: ExperimentalServiceResourceDetector{}},
+			},
 		},
 		SchemaUrl: ptr("https://opentelemetry.io/schemas/1.16.0"),
 	},

otelconf/testdata/v1.0.0.json

@@ -515,7 +515,13 @@
                 "excluded": [
                     "process.command_args"
                 ]
-            }
+            },
+            "detectors": [
+                {"container": null},
+                {"host": null},
+                {"process": null},
+                {"service": null}
+            ]
         },
         "schema_url": "https://opentelemetry.io/schemas/1.16.0"
     },

otelconf/testdata/v1.0.0.yaml

@@ -841,16 +841,15 @@ resource:
     # Configure resource detectors.
     # Resource detector names are dependent on the SDK language ecosystem. Please consult documentation for each respective language. 
     # If omitted or null, no resource detectors are enabled.
-    # TODO: implement resource detectors https://github.com/open-telemetry/opentelemetry-go-contrib/issues/7252
-    # detectors:
-    #   - # Enable the container resource detector, which populates container.* attributes.
-    #     container:
-    #   - # Enable the host resource detector, which populates host.* and os.* attributes.
-    #     host:
-    #   - # Enable the process resource detector, which populates process.* attributes.
-    #     process:
-    #   - # Enable the service detector, which populates service.name based on the OTEL_SERVICE_NAME environment variable and service.instance.id.
-    #     service:
+    detectors:
+      - # Enable the container resource detector, which populates container.* attributes.
+        container:
+      - # Enable the host resource detector, which populates host.* and os.* attributes.
+        host:
+      - # Enable the process resource detector, which populates process.* attributes.
+        process:
+      - # Enable the service detector, which populates service.name based on the OTEL_SERVICE_NAME environment variable and service.instance.id.
+        service:
   # Configure resource schema URL.
   # If omitted or null, no schema URL is used.
   schema_url: https://opentelemetry.io/schemas/1.16.0