actualAttributes = parseResourceAttributes(bytes);
+ assertEquals(expectedAttributes, actualAttributes, "For case: " + caseName);
+ }
+
+ // ── parsing helpers ───────────────────────────────────────────────────────
+
+ /**
+ * Parses the resource message bytes into an attribute map while validating the protobuf wire
+ * format (field numbers and wire types) of every field read.
+ *
+ * {@code buildResourceMessage} returns a length-prefixed message with an outer tag (field 1,
+ * LEN wire type) followed by the Resource body size and body. Read the outer tag, then iterate
+ * over all {@code Resource.attributes} (field 1, LEN wire type). Each attribute is a {@code
+ * KeyValue} whose {@code value} is an {@code AnyValue} containing a {@code string_value}.
+ */
+ private static Map parseResourceAttributes(byte[] bytes) throws IOException {
+ // Read the outer tag (field 1, LEN wire type) that wraps the Resource body
+ CodedInputStream outer = CodedInputStream.newInstance(bytes);
+ int outerTag = outer.readTag();
+ assertEquals(1, WireFormat.getTagFieldNumber(outerTag), "outer field is Resource (field 1)");
+ assertEquals(WireFormat.WIRETYPE_LENGTH_DELIMITED, WireFormat.getTagWireType(outerTag));
+ CodedInputStream resource = outer.readBytes().newCodedInput();
+
+ Map attributes = new LinkedHashMap<>();
+ while (!resource.isAtEnd()) {
+ // Each attribute is Resource.attributes (field 1, LEN wire type)
+ int tag = resource.readTag();
+ assertEquals(1, WireFormat.getTagFieldNumber(tag), "Resource.attributes is field 1");
+ assertEquals(WireFormat.WIRETYPE_LENGTH_DELIMITED, WireFormat.getTagWireType(tag));
+
+ // Read the full KeyValue body
+ CodedInputStream kv = resource.readBytes().newCodedInput();
+
+ String key = readKeyField(kv);
+ CodedInputStream av = readAnyValueField(kv);
+
+ // Read AnyValue.string_value (field 1, LEN)
+ int avTag = av.readTag();
+ assertEquals(1, WireFormat.getTagFieldNumber(avTag), "AnyValue.string_value is field 1");
+ assertEquals(WireFormat.WIRETYPE_LENGTH_DELIMITED, WireFormat.getTagWireType(avTag));
+ String value = av.readString();
+ assertTrue(av.isAtEnd(), "no extra fields in AnyValue");
+ assertTrue(kv.isAtEnd(), "no extra fields in KeyValue");
+
+ attributes.put(key, value);
+ }
+ return attributes;
+ }
+
+ /** Reads the {@code KeyValue.key} field (field 1, LEN) and returns the string value. */
+ private static String readKeyField(CodedInputStream kv) throws IOException {
+ int tag = kv.readTag();
+ assertEquals(1, WireFormat.getTagFieldNumber(tag), "KeyValue.key is field 1");
+ assertEquals(WireFormat.WIRETYPE_LENGTH_DELIMITED, WireFormat.getTagWireType(tag));
+ return kv.readString();
+ }
+
+ /**
+ * Reads the {@code KeyValue.value} field (field 2, LEN) and returns a stream over the {@code
+ * AnyValue} body.
+ */
+ private static CodedInputStream readAnyValueField(CodedInputStream kv) throws IOException {
+ int tag = kv.readTag();
+ assertEquals(2, WireFormat.getTagFieldNumber(tag), "KeyValue.value is field 2");
+ assertEquals(WireFormat.WIRETYPE_LENGTH_DELIMITED, WireFormat.getTagWireType(tag));
+ return kv.readBytes().newCodedInput();
+ }
+}
diff --git a/dd-java-agent/agent-otel/otel-bootstrap/src/test/resources/opentelemetry/proto/resource/v1/resource.proto b/dd-java-agent/agent-otel/otel-bootstrap/src/test/resources/opentelemetry/proto/resource/v1/resource.proto
new file mode 100644
index 0000000000..42c5913cfa
--- /dev/null
+++ b/dd-java-agent/agent-otel/otel-bootstrap/src/test/resources/opentelemetry/proto/resource/v1/resource.proto
@@ -0,0 +1,45 @@
+// Copyright 2019, OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+
+package opentelemetry.proto.resource.v1;
+
+import "opentelemetry/proto/common/v1/common.proto";
+
+option csharp_namespace = "OpenTelemetry.Proto.Resource.V1";
+option java_multiple_files = true;
+option java_package = "io.opentelemetry.proto.resource.v1";
+option java_outer_classname = "ResourceProto";
+option go_package = "go.opentelemetry.io/proto/otlp/resource/v1";
+
+// Resource information.
+message Resource {
+ // Set of attributes that describe the resource.
+ // Attribute keys MUST be unique (it is not allowed to have more than one
+ // attribute with the same key).
+ // The behavior of software that receives duplicated keys can be unpredictable.
+ repeated opentelemetry.proto.common.v1.KeyValue attributes = 1;
+
+ // The number of dropped attributes. If the value is 0, then
+ // no attributes were dropped.
+ uint32 dropped_attributes_count = 2;
+
+ // Set of entities that participate in this Resource.
+ //
+ // Note: keys in the references MUST exist in attributes of this message.
+ //
+ // Status: [Development]
+ repeated opentelemetry.proto.common.v1.EntityRef entity_refs = 3;
+}