Implement getBackend.

src/apphosting/backend.ts

@@ -17,7 +17,7 @@
 import { addServiceAccountToRoles } from "../gcp/resourceManager";
 import * as iam from "../gcp/iam";
 import { FirebaseError, getErrStatus, getError } from "../error";
-import { promptOnce } from "../prompt";
+import { promptOnce, confirm } from "../prompt";
 import { DEFAULT_LOCATION } from "./constants";
 import { ensure } from "../ensureApiEnabled";
 import * as deploymentTool from "../deploymentTool";
@@ -48,7 +48,7 @@
     // SSL.
     const maybeNodeError = err as { cause: { code: string }; code: string };
     if (
       /HANDSHAKE_FAILURE/.test(maybeNodeError?.cause?.code) ||
       "EPROTO" === maybeNodeError?.code
     ) {
       return false;
@@ -263,10 +263,10 @@
 async function promptNewBackendId(
   projectId: string,
   location: string,
   prompt: any,
 ): Promise<string> {
   while (true) {
     const backendId = await promptOnce(prompt);
     try {
       await apphosting.getBackend(projectId, location, backendId);
     } catch (err: unknown) {
@@ -443,7 +443,7 @@
   let { unreachable, backends } = await apphosting.listBackends(projectId, "-");
   if (unreachable && unreachable.length !== 0) {
     logWarning(
       `The following locations are currently unreachable: ${unreachable}.\n` +
         "If your backend is in one of these regions, please try again later.",
     );
   }
@@ -466,11 +466,59 @@
   backends.forEach((backend) =>
     backendsByLocation.set(apphosting.parseBackendName(backend.name).location, backend),
   );
   const location = await promptOnce({
     name: "location",
     type: "list",
     message: locationDisambugationPrompt,
     choices: [...backendsByLocation.keys()],
   });
   return backendsByLocation.get(location)!;
 }
+
+/**
+ * Fetches a backend from the server. If there are multiple backends with the name, it will fetch the first
+ * in the list and warn the user that there are other backends with the same name that need to be deleted. If
+ * the force option is specified nad multiple backends have the same name, it throws an error.
+ */
+export async function getBackend(
+  projectId: string,
+  backendId: string,
+  force?: boolean,
+): Promise<apphosting.Backend> {
+  // TODO: call apphosting.getBackend() once all duplicate named backends have been deleted.
+  let { unreachable, backends } = await apphosting.listBackends(projectId, "-");
+  backends = backends.filter(
+    (backend) => apphosting.parseBackendName(backend.name).id === backendId,
+  );
+  if (backends.length > 0) {
+    if (backends.length > 1) {
+      logWarning(
+        `You have multiple backends with the same ${backendId} ID. This is no longer supported. ` +
+        "Please delete and recreate any backends that share an ID with another backend."
+      );
+      if (force) {
+        throw new FirebaseError(
+          `Force cannot be used when multiple backends share the same ID`,
+        );
+      }
+      const options = { force: force, nonInteractive: false };
+      const confirmed = await confirm({
+	...options,
+	message: `Using backend ${backends[0].name} continue?`,
+      });
+      if (!confirmed) {
+	throw new FirebaseError("Command aborted.");
+      }
+    }
+    return backends[0];
+  }
+  if (unreachable && unreachable.length !== 0) {
+    logWarning(
+      `Backends with the following primary regions are unreachable: ${unreachable}.\n` +
+	"If your backend is in one of these regions, please try again later."
+    );
+  };
+  throw new FirebaseError(
+    `No backend named ${backendId} found.`,
+  );
+}