feat: add diagnostics and telemetry runtime

src/adapters/diagnostics/bounded-diagnostics.ts

@@ -0,0 +1,102 @@
+import type { DiagnosticsPort } from "../../application/ports/diagnostics-port.js";
+import {
+  projectDiagnosticRecord,
+  safeErrorKind,
+  type DiagnosticRecord,
+  type DiagnosticRecordInput,
+} from "../../contracts/diagnostics.js";
+import { projectTelemetryEvent } from "../../contracts/telemetry.js";
+
+export const noOpDiagnostics: DiagnosticsPort = Object.freeze({
+  record() {},
+});
+
+export function createDiagnosticsAdapter(
+  options: Readonly<{
+    maxEntries?: number;
+    now?: () => number;
+    sink?: (record: DiagnosticRecord) => void;
+  }> = {},
+) {
+  const maxEntries = Math.max(1, options.maxEntries ?? 100);
+  const entries: DiagnosticRecord[] = [];
+  const droppedReasons = new Map<string, number>();
+
+  function drop(reason: string) {
+    droppedReasons.set(reason, (droppedReasons.get(reason) ?? 0) + 1);
+  }
+
+  function record(input: DiagnosticRecordInput) {
+    try {
+      const projected = projectDiagnosticRecord(input, options.now);
+      if (!projected.success) {
+        drop(projected.reason);
+        return;
+      }
+      if (entries.length >= maxEntries) {
+        entries.shift();
+        drop("queue-full");
+      }
+      entries.push(projected.record);
+      try {
+        options.sink?.(projected.record);
+      } catch {
+        drop("sink-failure");
+      }
+    } catch {
+      drop("serialization-failure");
+    }
+  }
+
+  return Object.freeze({
+    record,
+    entries: () => structuredClone(entries) as readonly DiagnosticRecord[],
+    dropped: () => Object.freeze(Object.fromEntries(droppedReasons)),
+  });
+}
+
+type BootSafeContext = Readonly<{
+  kind?: string;
+  buildId?: string;
+  configSchemaVersion?: string;
+  supportReference?: string;
+}>;
+
+let lastBootEvidence:
+  | Readonly<{
+      diagnostic: DiagnosticRecord | null;
+      telemetry: Readonly<Record<string, unknown>> | null;
+    }>
+  | undefined;
+
+export function recordBootFailure(
+  error: unknown,
+  safe: BootSafeContext,
+  now: () => number = Date.now,
+) {
+  const errorKind =
+    typeof safe.kind === "string" ? safe.kind : safeErrorKind(error);
+  const attributes = {
+    error_kind: errorKind,
+    build_id: safe.buildId ?? "unknown",
+    config_schema_version: safe.configSchemaVersion ?? "unknown",
+  };
+  const diagnostic = projectDiagnosticRecord(
+    {
+      level: "error",
+      eventId: "app.boot.failed",
+      context: attributes,
+    },
+    now,
+  );
+  const telemetry = projectTelemetryEvent("app.boot.failed", attributes, now);
+  lastBootEvidence = Object.freeze({
+    diagnostic: diagnostic.success ? diagnostic.record : null,
+    telemetry: telemetry.success ? telemetry.event : null,
+  });
+  return lastBootEvidence;
+}
+
+export function getLastBootEvidence() {
+  return lastBootEvidence ? structuredClone(lastBootEvidence) : undefined;
+}