samples-typescript

• Running
  • In browser
  • Locally
  • Scaffold
• Samples
  • Basic
  • API demos
    • Activity APIs and design patterns
    • Workflow APIs
    • Production APIs
    • Advanced APIs
    • Test APIs
  • Full-stack apps
• External apps & libraries
• Contributing
  • Upgrading the SDK version
  • Config files

Each directory in this repo is a sample Temporal project built with the TypeScript SDK (see docs and API reference).

Running

In browser

The fastest way to try out these samples is running them in the browser:

• Gitpod: One click to try (there is a good free tier)
• GitHub Codespaces (if your org admin has enabled this) - 90 second video demo

Locally

Run Temporal Server:

brew install temporal
temporal server start-dev

(or use a different installation method)

Use Node version 16+:

• Install Node 16:
  • Mac: brew install node@16
  • Other: nodejs.org/en/download/
• Or use a Node version manager: fnm

Run the hello-world sample:

git clone https://github.com/temporalio/samples-typescript.git
cd samples-typescript/hello-world
npm i
npm start

and in another terminal:

npm run workflow

Scaffold

To scaffold a new project from one of these samples, run:

npx @temporalio/create@latest my-project --sample sample-name

or:

npx @temporalio/create@latest my-project

and you'll be given the list of sample options.

Samples

Basic

• Basic hello world: Simple example of a Workflow Definition and an Activity Definition.
  • Variant: Basic hello world with mTLS shows how to connect to your Temporal Cloud namespace with mTLS authentication.
• Pure ES Modules: Configure Temporal with TypeScript and Pure ESM.
• JavaScript: The Hello World sample in JavaScript instead of TypeScript.

API demos

Activity APIs and design patterns

• Activities Examples:
  • makeHTTPRequest: Make an external HTTP request in an Activity (using axios).
  • cancellableFetch: Make a cancellable HTTP request with cancellationSignal.
  • doSomethingAsync: Complete an Activity async with AsyncCompletionClient.
• Activity Cancellation and Heartbeating: Heartbeat progress for long running activities and cancel them.
• Dependency Injection: Share dependencies between activities (for example, when you need to initialize a database connection once and then pass it to multiple activities).
• Worker-Specific Task Queues: Use a unique task queue per Worker to have certain Activities only run on that specific Worker. For instance for a file processing Workflow, where the first Activity is downloading a file, and subsequent Activities need to operate on that file. (If multiple Workers were on the same queue, subsequent Activities may get run on different machines that don't have the downloaded file.)

Workflow APIs

• Timers:

  • The progress example demonstrates how to use the sleep function from @temporalio/workflow.
  • Timer Examples:
    • Send a notification to the customer if their order is taking longer than expected (using a Promise.race between the order activity and sleep).
    • Create an UpdatableTimer that can be slept on, and at the same time, have its duration updated via Signals.

• Signals and Triggers:

  • The Signals and Queries example demonstrates the usage of Signals, Queries, and Workflow Cancellation.
  • Mutex: Workflows send Signals to each other in this example of lockWorkflow acting as a mutex.
  • State: The Workflow maintains state in a Map<string, number>, and the state can be updated and read via a Signal and a Query.
  • Async activity completion: Example of an Expense reporting Workflow that communicates with a server API. Shows how to kick off a Workflow and manually complete it at an arbitrarily later date.

• Schedules: Schedule Workflows.

• Cron Workflows: Schedule a cron job. DEPRECATED: use Schedules instead.

• Child Workflows: Start and control Child Workflows.

• Infinite Workflows: Use the continueAsNew API for indefinitely long running Workflows.

• Search Attributes: Create, set, upsert, and read Search Attributes.

• Subscriptions

Production APIs

• Production Build: Build code in advance for faster Worker startup times.
• Debugging: The vscode-debugger sample shows how to use the Temporal VS Code plugin to debug a running or completed Workflow Execution.
• Patching: Patch in new Workflow code when making updates to Workflows that have executions in progress in production.
• Custom Logger: Use a winston logger to get logs out of all SDK components.
• Sinks: Use Sinks to extract data out of Workflows for alerting/logging/metrics/tracing purposes.
• Worker Versioning: Version Workers with Build IDs in order to deploy incompatible changes to Workflow code.
• Protobufs: Use Protobufs.
• Custom Payload Converter: Customize data serialization by creating a PayloadConverter that uses EJSON to convert Dates, binary, and regexes.
• Monorepos:
  • /monorepo-folders: yarn workspace with packages for a web frontend, API server, Worker, and Workflows/Activities.
  • psigen/temporal-ts-example: yarn workspace containerized with tilt. Includes temporalite, parcel, and different packages for Workflows and Activities.
• Polyglot: Use TS alongside other languages

Advanced APIs

• Interceptors:
  • OpenTelemetry: Use the Interceptors feature to add OpenTelemetry metrics reporting to your workflows.
  • Query Subscriptions: Use Redis Streams, Immer, and SDK Interceptors to subscribe to Workflow state.
• gRPC calls: Make raw gRPC calls for advanced queries not covered by the WorkflowClient API.

Test APIs

• Mocha with code coverage or Jest
• Time skipping

Full-stack apps

• Next.js:
  • One-click e-commerce: Buy an item with one click, and the Workflow will wait 5 seconds to see if the user cancels before it executes the order.
  • Food delivery: Multi-step business process with Signals, Queries, Activities, timeouts, and List Workflow API. Turborepo monorepo with 2 Next.js apps and a tRPC API.

External apps & libraries

The below projects are maintained outside this repo and may not be up to date.

• Express:
  • vkarpov15/temporal-ecommerce-ts: The cartWorkflow used in this blog series
  • temporal-rest: Express middleware router that automatically exposes endpoints for Workflows, Signals, and Queries.
• Remix:
  • gustavofsantos/temporal-survey
• NestJS:
  • nestjs-temporal
• Chatbots:
  • JoshuaKGoldberg/temporal-adventure-bot: Choose-your-own-adventure Slack/Discord chatbot (see tutorial and video)
• Caching:
  • vkarpov15/temporal-api-caching-example: Cache data from a third-party API (see blog post)
• DSL Control Flows:
  • YAML DSL Interpreter: Make Workflows interpret a custom YAML-based Domain Specific Language of your design.
  • XState Interpreter: Interpret XState state charts in a Workflow. Presented at the November 2021 meetup.
• URL Scraping
  • andreasasprou/temporal-url-batch-scraping
• Nx Monorepo
  • nubunto/nx-with-temporal

Contributing

External contributions are very welcome! 🤗 (Big thank you to those who have already contributed 🙏)

Before submitting a major PR, please find consensus on it in Issues.

To get started developing, run:

git clone https://github.com/temporalio/samples-typescript.git
cd samples-typescript
npm install
npm run prepare
npm run bootstrap

Prettier and ESLint are run on each commit, but you can also run them manually:

npm run format
npm run lint

Dependencies

• The docs and tutorials depend on SNIPSTART and SNIPEND comments in samples. Make sure to search through the docs and learn repos to make sure a snippet is unused before removing it.
• There are blog posts and a PDF that depend on the file structure of the food-delivery/ sample.

Updating to latest SDK version

lerna exec -- npm update

Upgrading the SDK version in package.jsons

npx zx .scripts/upgrade-versions.mjs 'VERSION_STRING_HERE'
npm run format

Config files

Also on each commit, config files from .shared/ are copied into each sample directory, overwriting the sample directory's config files (with a few exceptions listed in .scripts/copy-shared-files.mjs). So if you're editing config files, you usually want to be editing the versions in .shared/.

The .post-create file is a chalk template that is displayed in the command line after someone uses npx @temporalio/create. If you're adding a sample that requires different instructions from the default message, then add your sample name to POST_CREATE_EXCLUDE and your message template to your-sample/.post-create.