Core package for GCP Cloud Run

This package contains some core functionality for Node.js services running on Google Cloud Run, such as logging and error handling.

• Development
• Install
• Create a HTTP service
• Logging
  • Logging in HTTP services
  • Logging in scripts / GCP Cloud Run Jobs
  • LOG_LEVEL - Control minimum log level
• Routing
• Error handling
• Sentry integration
• Request validation with parseRequest
• Graceful shutdown
• Pub/Sub helpers
• Detecting Cloud Run environment
• Peculiarities

Development

▶ pnpm install
▶ pnpm test

Publishing the package:

▶ pn changeset  # create a new changeset
▶ pn changeset version  # updates version number and changelog 
▶ git commit -m "publish vX.X.X"
▶ pn changeset publish
▶ git push --follow-tags

Install

▶ npm install @biblioteksentralen/cloud-run-core

Create a HTTP service

To create an Express-based HTTP service:

// src/start.ts
import { createService } from "@biblioteksentralen/cloud-run-core";
import { z } from "zod";

const projectId = z.string().parse(process.env.GCP_PROJECT_ID);
const service = createService("fun-service", { projectId });

service.router.get("/", async (req, res) => {
  req.log.info(`Hello log!`);
  // ...
});

service.start();

Logging

Logging in HTTP services

The HTTP service comes pre-configured with a logging middleware that sets up Pino to structure logs for Google Cloud Logging with trace context. The logger is added to the Express Request context, so it can be used in all request handlers:

// src/endpoints/funRequestHandler.ts
import { Request, Response } from "@biblioteksentralen/cloud-run-core";

export async function funRequestHandler(req: Request, res: Response): Promise<void> {
  req.log.info(`Hello log!`);
}

// src/start.ts
// ...
import { funRequestHandler } from "./endpoints/funRequestHandler.js";

// ...
service.router.get("/", funRequestHandler);

Logging in scripts / GCP Cloud Run Jobs

In scripts / GCP Cloud Run Jobs:

import { logger } from "@biblioteksentralen/cloud-run-core"

logger.info({ someProperty: "someValue" }, "Hello world")

The logger is configured so it formats logs as JSON structured for GCP Cloud Logging when running in GCP, or when output is piped to another process (no TTY), and with pino-pretty otherwise.

To manually disable pino-pretty, set the environment variable PINO_PRETTY=false.

LOG_LEVEL - Control minimum log level

The environment variable LOG_LEVEL can be used to control the minimum log level. Defaults to debug.

Routing

Use createRouter() to create modular, mountable route handlers (uses express.Router()):

// src/start.ts
import { createService, createRouter } from "@biblioteksentralen/cloud-run-core";
import { z } from "zod";

const projectId = z.string().parse(process.env.GCP_PROJECT_ID);
const service = createService("fun-service", { projectId });

const adminRouter = createRouter()

adminRouter.get("/", async (req, res) => {
  req.log.info(`Hello admin`);
  // ...
});

service.router.use("/admin", adminRouter);

service.start();

Error handling

This package provides an error handling middleware that is automatically attached to the service when you start the service using service.start(), inspired by How to Handle Errors in Express with TypeScript.

AppError is a base class to be used for all known application errors (that is, all errors we throw ourselves).

// src/endpoints/funRequestHandler.ts
import { AppError, Request, Response } from "@biblioteksentralen/cloud-run-core";

export async function funRequestHandler(req: Request, res: Response) {
  // ...
  throw new AppError('🔥 Databasen har brent ned');
  // ...
}

As long as errors are thrown before writing the response has started, a JSON error response is produced on the form:

{ "error": "🔥 Databasen har brent ned" }

By default, errors based on AppError are considered operational and displayed in responses. If an error should not be displayed, set isOperational: false when constructing the error:

throw new AppError('🔥 Databasen har brent ned', { isOperational: false });

This results in a generic error response (but the original error is still logged):

{ "error": "Internal server error" }

A generic error response will also be shown for any unknown error, that is, any error that is not based on AppError) is thrown. All errors, both known and unknown, are logged.

By default, errors use status code 500. To use another status code:

throw new AppError('💤 Too early', { httpStatus: 425 });

The package also provides a few subclasses of AppError for common use cases, such as ClientRequestError (yields 400 response) and Unauthorized (yields 401 response).

throw new Unauthorized('🔒 Unauthorized');

Sentry integration

Set sentry.dsn when creating the client to enable Sentry error reporting and telemetry.

import { createService } from "@biblioteksentralen/cloud-run-core";

const service = createService("fun-service", { 
  sentry: {
    dsn: process.env.SENTRY_DSN,
    tracesSampleRate: 0.1,
    environment: process.env.NODE_ENV, // or similar
    ...
  },
  ...
});

Request validation with parseRequest

The parseRequest parses a request body using a Zod schema. If the input is invalid, the request will be logged together with the errors, and an "invalid request" is returned to the sender.

import { Request, Response, parseRequest } from "@biblioteksentralen/cloud-run-core";
import { z } from "zod";

export async function funRequestHandler(req: Request, res: Response) {
  const { isbn13 } = parseRequest(req.body, z.object({
    "isbn13": z.string().regex(/^978[0-9]{10}$/),
  }));

  res.json({ status: "ok", isbn13 });
}

Graceful shutdown

The package uses http-terminator to gracefully terminate the HTTP server when the process exists (on SIGTERM). An event, shutdown, is emitted after the server has shut down. You can listen to this if you want to do additional cleanup, such as closing database connections.

// src/start.ts
import { createService } from "@biblioteksentralen/cloud-run-core";
import { z } from "zod";

const projectId = z.string().parse(process.env.GCP_PROJECT_ID);
const service = createService("fun-service", { projectId });

service.on("shutdown", async () => {
  await db.close()
});

// ...

service.start();

Pub/Sub helpers

The package provides a helper function to parse and validate Pub/Sub messages delivered through push delivery.

The package is agnostic when it comes to which schema parsing/validation library to use. We like Zod for its usability, and have added support for it in the errorHandler, but it's not very performant (https://moltar.github.io/typescript-runtime-type-benchmarks/), so you might pick something else if performance is important (if you do, remember to throw ClientRequestError when validation fails).

import { z } from "zod";
import {
  parsePubSubMessage,
  Request,
  Response,
} from "@biblioteksentralen/cloud-run-core";

const messageSchema = z.object({
  table: z.string(),
  key: z.number(),
});

app.post("/", async (req: Request, res: Response) => {
  const message = parsePubSubMessage(req, (data) => messageSchema.parse(JSON.parse(data)));
  // ...
});

Detecting Cloud Run environment

import { isCloudRunEnvironment } from "@biblioteksentralen/cloud-run-core";

isCloudRunEnvironment()

will return true if running as a Cloud Run Service or Job.

Peculiarities

• We include @types/express as a dependency, not a devDependency, because we extend and re-export the Request interface. Initially we kept it under devDependencies, but then all package consumers would have to install the package themselves. Not sure what's considered best practice in cases like this though.

• @sentry-pakkene kan av og til komme ut av sync med hverandre. De jobber med å redusere mengden pakker for å redusere problemet: https://github.com/getsentry/sentry-javascript/issues/8965#issuecomment-1709923865 Inntil videre kan en prøve å oppdatere alle pakker og se om en klarer å få like versjoner fra pn ls --depth 3 @sentry/types