From 12aeb8bf37dc74efbec53f9d272d1e8f046d8f81 Mon Sep 17 00:00:00 2001
From: Danijel Martinek <danijel@fraqtal.xyz>
Date: Mon, 11 May 2026 11:23:19 +0200
Subject: [PATCH] feat(core-shared): OTel resource builder

---
 .../src/instrumentation/otel/resource.test.ts | 38 +++++++++++++++++++
 .../src/instrumentation/otel/resource.ts      | 22 +++++++++++
 2 files changed, 60 insertions(+)
 create mode 100644 packages/core-shared/src/instrumentation/otel/resource.test.ts
 create mode 100644 packages/core-shared/src/instrumentation/otel/resource.ts

diff --git a/packages/core-shared/src/instrumentation/otel/resource.test.ts b/packages/core-shared/src/instrumentation/otel/resource.test.ts
new file mode 100644
index 0000000..8b61102
--- /dev/null
+++ b/packages/core-shared/src/instrumentation/otel/resource.test.ts
@@ -0,0 +1,38 @@
+import { describe, it, expect } from "vitest";
+import { buildResource } from "./resource";
+import {
+  ATTR_SERVICE_NAME,
+  ATTR_SERVICE_VERSION,
+  ATTR_DEPLOYMENT_ENVIRONMENT_NAME,
+} from "@opentelemetry/semantic-conventions/incubating";
+
+describe("buildResource", () => {
+  it("populates service name, version, and environment", () => {
+    const r = buildResource({
+      serviceName: "web-next",
+      serviceVersion: "1.0.0",
+      environment: "production",
+    });
+    expect(r.attributes[ATTR_SERVICE_NAME]).toBe("web-next");
+    expect(r.attributes[ATTR_SERVICE_VERSION]).toBe("1.0.0");
+    expect(r.attributes[ATTR_DEPLOYMENT_ENVIRONMENT_NAME]).toBe("production");
+  });
+
+  it("populates namespace when provided", () => {
+    const r = buildResource({
+      serviceName: "web-next",
+      environment: "production",
+      namespace: "template-vertical",
+    });
+    expect(r.attributes["service.namespace"]).toBe("template-vertical");
+  });
+
+  it("omits version and namespace when not provided", () => {
+    const r = buildResource({
+      serviceName: "web-next",
+      environment: "production",
+    });
+    expect(r.attributes[ATTR_SERVICE_VERSION]).toBeUndefined();
+    expect(r.attributes["service.namespace"]).toBeUndefined();
+  });
+});
diff --git a/packages/core-shared/src/instrumentation/otel/resource.ts b/packages/core-shared/src/instrumentation/otel/resource.ts
new file mode 100644
index 0000000..dfccd37
--- /dev/null
+++ b/packages/core-shared/src/instrumentation/otel/resource.ts
@@ -0,0 +1,22 @@
+import { Resource } from "@opentelemetry/resources";
+
+export type BuildResourceOpts = {
+  serviceName: string;
+  serviceVersion?: string;
+  environment: string;
+  namespace?: string;
+};
+
+/**
+ * Builds an OpenTelemetry Resource with semantic-convention attributes.
+ * Each app constructs its own resource at startup (per-app service name).
+ */
+export function buildResource(opts: BuildResourceOpts): Resource {
+  const attrs: Record<string, string> = {
+    "service.name": opts.serviceName,
+    "deployment.environment.name": opts.environment,
+  };
+  if (opts.serviceVersion) attrs["service.version"] = opts.serviceVersion;
+  if (opts.namespace) attrs["service.namespace"] = opts.namespace;
+  return new Resource(attrs);
+}