feat: validate runtime configuration before mount

src/bootstrap/load-runtime-config.js

@@ -0,0 +1,104 @@
+import { assertSafeConfigNames, getBuildConfig } from "../contracts/env.js";
+import { validateRuntimeConfig } from "./runtime-config-schema.js";
+
+export class BootConfigError extends Error {
+  /**
+   * @param {string} code
+   * @param {{ buildId: string, configSchemaVersion?: string, releaseId?: string }} safe
+   */
+  constructor(code, safe) {
+    super("Runtime configuration could not be loaded");
+    this.name = "BootConfigError";
+    this.kind = "BOOT_CONFIG_FAILURE";
+    this.code = code;
+    this.safe = Object.freeze({
+      kind: this.kind,
+      code,
+      buildId: safe.buildId,
+      configSchemaVersion: safe.configSchemaVersion,
+      releaseId: safe.releaseId,
+      supportReference: `${safe.buildId}:${code}`,
+    });
+  }
+}
+
+/**
+ * @param {{
+ *   fetcher?: typeof fetch,
+ *   buildConfig?: ReturnType<typeof getBuildConfig>,
+ *   now?: () => number
+ * }} [options]
+ */
+export async function loadRuntimeConfig(options = {}) {
+  const fetcher = options.fetcher ?? fetch;
+  const buildConfig = options.buildConfig ?? getBuildConfig();
+  const now = options.now ?? performance.now.bind(performance);
+  const startedAt = now();
+
+  let response;
+  try {
+    response = await fetcher(buildConfig.runtimeConfigUrl, {
+      cache: "no-store",
+      headers: { Accept: "application/json" },
+    });
+  } catch {
+    throw new BootConfigError("CONFIG_FETCH_FAILED", {
+      buildId: buildConfig.buildId,
+    });
+  }
+
+  if (!response.ok) {
+    throw new BootConfigError("CONFIG_HTTP_FAILED", {
+      buildId: buildConfig.buildId,
+    });
+  }
+
+  let rawConfig;
+  try {
+    rawConfig = await response.json();
+  } catch {
+    throw new BootConfigError("CONFIG_JSON_INVALID", {
+      buildId: buildConfig.buildId,
+    });
+  }
+
+  if (!rawConfig || typeof rawConfig !== "object" || Array.isArray(rawConfig)) {
+    throw new BootConfigError("CONFIG_SHAPE_INVALID", {
+      buildId: buildConfig.buildId,
+    });
+  }
+
+  try {
+    assertSafeConfigNames(rawConfig);
+  } catch {
+    throw new BootConfigError("CONFIG_SECRET_NAME_REJECTED", {
+      buildId: buildConfig.buildId,
+    });
+  }
+
+  const validated = validateRuntimeConfig(rawConfig);
+  if (!validated.success) {
+    throw new BootConfigError("CONFIG_SCHEMA_INVALID", {
+      buildId: buildConfig.buildId,
+      configSchemaVersion:
+        typeof rawConfig.CONFIG_SCHEMA_VERSION === "string"
+          ? rawConfig.CONFIG_SCHEMA_VERSION
+          : undefined,
+      releaseId: typeof rawConfig.RELEASE_ID === "string" ? rawConfig.RELEASE_ID : undefined,
+    });
+  }
+
+  if (validated.data.BUILD_ID && validated.data.BUILD_ID !== buildConfig.buildId) {
+    throw new BootConfigError("CONFIG_BUILD_MISMATCH", {
+      buildId: buildConfig.buildId,
+      configSchemaVersion: validated.data.CONFIG_SCHEMA_VERSION,
+      releaseId: validated.data.RELEASE_ID,
+    });
+  }
+
+  return Object.freeze({
+    config: validated.data,
+    build: buildConfig,
+    validationDurationMs: now() - startedAt,
+  });
+}