From aaaa79ebc519d50ed3f220714ac8c9d9e9201af6 Mon Sep 17 00:00:00 2001 From: Chris O'Hara Date: Mon, 1 Jul 2024 13:00:22 +1000 Subject: [PATCH 1/4] Port README from Python --- README.md | 303 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 303 insertions(+) create mode 100644 README.md diff --git a/README.md b/README.md new file mode 100644 index 0000000..4d90d7a --- /dev/null +++ b/README.md @@ -0,0 +1,303 @@ +

+ + + dispatch logo + +

+ +# dispatch-go + +[![Test](https://github.com/dispatchrun/dispatch-go/actions/workflows/test.yml/badge.svg?branch=main)](https://github.com/dispatchrun/dispatch-go/actions/workflows/test.yml) +[![Go Reference](https://pkg.go.dev/badge/github.com/dispatchrun/dispatch-go.svg)](https://pkg.go.dev/github.com/dispatchrun/dispatch-go) +[![Apache 2 License](https://img.shields.io/badge/license-Apache%202-blue.svg)](LICENSE) +[![Discord](https://img.shields.io/discord/1126309607166464131?label=Discord)](Discord) + +Go package to develop applications with Dispatch. + +[signup]: https://console.dispatch.run/ + +- [What is Dispatch?](#what-is-dispatch) +- [Installation](#installation) + - [Installing the Dispatch CLI](#installing-the-dispatch-cli) + - [Installing the Dispatch SDK](#installing-the-dispatch-sdk) +- [Usage](#usage) + - [Writing Dispatch Applications](#writing-dispatch-applications) + - [Running Dispatch Applications](#running-dispatch-applications) + - [Writing Transactional Applications with Dispatch](#writing-transactional-applications-with-dispatch) + - [Integration with HTTP servers](#integration-with-http-servers) + - [Configuration](#configuration) + - [Serialization](#serialization) +- [Examples](#examples) +- [Contributing](#contributing) + +## What is Dispatch? + +Dispatch is a cloud service for developing scalable and reliable applications in +Go, including: + +- **Event-Driven Architectures** +- **Background Jobs** +- **Transactional Workflows** +- **Multi-Tenant Data Pipelines** + +Dispatch differs from alternative solutions by allowing developers to write +simple Go code: it has a **minimal API footprint**, which usually only +requires wrapping a function (no complex framework to learn), failure +recovery is built-in by default for transient errors like rate limits or +timeouts, with a **zero-configuration** model. + +To get started, follow the instructions to [sign up for Dispatch][signup] 🚀. + +## Installation + +### Installing the Dispatch CLI + +As a pre-requisite, we recommend installing the Dispatch CLI to simplify the +configuration and execution of applications that use Dispatch. On macOS, this +can be done easily using [Homebrew](https://docs.brew.sh/): + +```console +brew tap dispatchrun/dispatch +brew install dispatch +``` + +Alternatively, you can download the latest `dispatch` binary from the +[Releases](https://github.com/dispatchrun/dispatch/releases) page. + +_Note that this step is optional, applications that use Dispatch can run without +the CLI, passing configuration through environment variables or directly in the +code. However, the CLI automates the onboarding flow and simplifies the +configuration, so we recommend starting with it._ + +### Installing the Dispatch SDK + +The Go SDK can be added as a dependency using: + +```console +go mod init dispatch-example # if starting fresh +go get github.com/dispatchrun/dispatch-go@latest +``` + +## Usage + +### Writing Dispatch Applications + +The following snippet shows how to write a simple Dispatch application +that does the following: + +1. declare a Dispatch function named `greet` which can run asynchronously +1. start a Dispatch endpoint to handle function calls +1. schedule a call to `greet` with the argument `World` + +```go +# main.go +package main + +import ( + "context" + "fmt" + "log" + + "github.com/dispatchrun/dispatch-go" +) + +func main() { + greet := dispatch.Func("greet", func(ctx context.Context, msg string) (any, error) { + fmt.Printf("Hello, %s!\n", msg) + return nil, nil + }) + + endpoint, err := dispatch.New(greet) + if err != nil { + log.Fatal(err) + } + + go func() { + if _, err := greet.Dispatch(context.Background(), "World"); err != nil { + log.Fatal(err) + } + }() + + if err := endpoint.ListenAndServe(); err != nil { + log.Fatal(err) + } +} +``` + +Obviously, this is just an example, a real application would perform much more +interesting work, but it's a good start to get a sense of how to use Dispatch. + +### Running Dispatch Applications + +The simplest way to run a Dispatch application is to use the Dispatch CLI, first +we need to login: + +```console +dispatch login +``` + +Then we are ready to run the example program we wrote above: + +```console +dispatch run -- go run main.go +``` + +### Writing Transactional Applications with Dispatch + +Dispatch functions are _coroutines_ that can be suspended and resumed at _await_ +points. The await points are durability checkpoints; if a function fails midway +through execution, it can be retried automatically from these checkpoints. + +```go +pipeline := dispatch.Func("pipeline", func (ctx context.Context, msg string) (string, error) { + // Each await point is a durability step, the functions can be run across the + // fleet of service instances and retried as needed without losing track of + // progress through the function execution. + msg, _ = transform1.Await(ctx, msg) + msg, _ = transform2.Await(ctx, msg) + return publish.Await(ctx, msg) +}) + +publish := dispatch.Func("publish", func (ctx context.Context, msg string) (*dispatchhttp.Response, error) { + // Each dispatch function runs concurrently to the others, even if it does + // blocking operations like this POST request, it does not prevent other + // concurrent operations from carrying on in the program. + return dispatchhttp.Post("https://somewhere.com/", bytes.NewBufferString(msg)) +}) + +transform1 := dispatch.Func("transform1", func (ctx context.Context, msg string) (string, error) { + // ... +}) + +transform2 := dispatch.Func("transform1", func (ctx context.Context, msg string) (string, error) { + // ... +}) +``` + +This model is composable and can be used to create fan-out/fan-in control flows. +`gather` can be used to wait on multiple concurrent calls: + +```go +process := dispatch.Func("process", func (ctx context.Context, msgs []string) ([]string, error) { + // Transform messages concurrently and await all of their results. + return transform.Gather(ctx, msgs) +}) + +transform := dispatch.Func("transform", func (ctx context.Context, msg string) (string, error) { + // ... +}) +``` + +Dispatch converts Go functions into _Distributed Coroutines_, which can be +suspended and resumed on any instance of a service across a fleet. For a deep +dive on these concepts, read our +[_Distributed Coroutines_](https://dispatch.run/blog/distributed-coroutines-in-python) +blog post. + +### Integration with HTTP servers + +Dispatch can be integrated into an existing HTTP server. + +In the example below, a request to `/` triggers an asynchronous call to the `greet` +function: + +```go +package main + +import ( + "context" + "fmt" + "log" + "net/http" + + "github.com/dispatchrun/dispatch-go" +) + +func main() { + greet := dispatch.Func("greet", func(ctx context.Context, msg string) (any, error) { + fmt.Printf("Hello, %s!\n", msg) + return nil, nil + }) + + endpoint, err := dispatch.New(greet) + if err != nil { + log.Fatal(err) + } + + mux := http.NewServeMux() + + mux.Handle(endpoint.Handler()) + + mux.Handle("/", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { + greet.Dispatch(r.Context(), "World") + w.WriteHeader(http.StatusOK) + })) + + if err := http.ListenAndServe("localhost:8000", mux); err != nil { + log.Fatal(err) + } +} +``` + +### Configuration + +The Dispatch CLI automatically configures the SDK, so manual configuration is +usually not required when running Dispatch applications. However, in some +advanced cases, it might be useful to explicitly set configuration options. + +In order for Dispatch to interact with functions remotely, the SDK needs to be +configured with the address at which the server can be reached. The Dispatch +API Key must also be set, and optionally, a public signing key should be +configured to verify that requests originated from Dispatch. These +configuration options can be passed as arguments to the +the `Dispatch` constructor, but by default they will be loaded from environment +variables: + +| Environment Variable | Value Example | +| :-------------------------- | :--------------------------------- | +| `DISPATCH_API_KEY` | `d4caSl21a5wdx5AxMjdaMeWehaIyXVnN` | +| `DISPATCH_ENDPOINT_URL` | `https://service.domain.com` | +| `DISPATCH_VERIFICATION_KEY` | `-----BEGIN PUBLIC KEY-----...` | + +### Serialization + +#### Inputs & Outputs + +Dispatch uses protobuf to serialize input and output values. + +The inputs and outputs must either be primitive values, list or maps +of primitive values, or have a type that implements one of the +following interfaces: +- `proto.Message` +- `encoding.TextMarshaler` +- `encoding.BinaryMarshaler` +- `json.Marshaler` + +#### Coroutine State + +Dispatch uses the [coroutine] library to serialize coroutines. + +[coroutine]: https://github.com/dispatchrun/coroutine + +The user must ensure that the contents of their stack frames are +serializable. + +For help with a serialization issues, please submit a [GitHub issue][issues]. + +[issues]: https://github.com/dispatchrun/dispatch-go/issues + +## Examples + +Check out the [examples](examples/) directory for code samples to help you get +started with the SDK. + +## Contributing + +Contributions are always welcome! Would you spot a typo or anything that needs +to be improved, feel free to send a pull request. + +Pull requests need to pass all CI checks before getting merged. Anything that +isn't a straightforward change would benefit from being discussed in an issue +before submitting a change. + +Remember to be respectful and open minded! From 379998aa792694436a25c2dd414d2a4262f25a07 Mon Sep 17 00:00:00 2001 From: Chris O'Hara Date: Mon, 1 Jul 2024 13:00:27 +1000 Subject: [PATCH 2/4] Add LICENSE --- LICENSE | 201 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 201 insertions(+) create mode 100644 LICENSE diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..a7aa8f9 --- /dev/null +++ b/LICENSE @@ -0,0 +1,201 @@ + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + + TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + + 1. 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From 4272930ef9c9eb6641a9ace15a9276cd0c84ee31 Mon Sep 17 00:00:00 2001 From: Chris O'Hara Date: Mon, 1 Jul 2024 13:04:40 +1000 Subject: [PATCH 3/4] Fixes --- README.md | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/README.md b/README.md index 4d90d7a..1388096 100644 --- a/README.md +++ b/README.md @@ -74,10 +74,11 @@ configuration, so we recommend starting with it._ The Go SDK can be added as a dependency using: ```console -go mod init dispatch-example # if starting fresh go get github.com/dispatchrun/dispatch-go@latest ``` +If you're starting fresh, don't forget to run `go mod init` first (e.g. `go mod init dispatch-example`). + ## Usage ### Writing Dispatch Applications @@ -169,7 +170,7 @@ transform1 := dispatch.Func("transform1", func (ctx context.Context, msg string) // ... }) -transform2 := dispatch.Func("transform1", func (ctx context.Context, msg string) (string, error) { +transform2 := dispatch.Func("transform2", func (ctx context.Context, msg string) (string, error) { // ... }) ``` @@ -179,7 +180,7 @@ This model is composable and can be used to create fan-out/fan-in control flows. ```go process := dispatch.Func("process", func (ctx context.Context, msgs []string) ([]string, error) { - // Transform messages concurrently and await all of their results. + // Transform messages concurrently and await the results. return transform.Gather(ctx, msgs) }) @@ -268,10 +269,10 @@ Dispatch uses protobuf to serialize input and output values. The inputs and outputs must either be primitive values, list or maps of primitive values, or have a type that implements one of the following interfaces: -- `proto.Message` - `encoding.TextMarshaler` - `encoding.BinaryMarshaler` - `json.Marshaler` +- `proto.Message` #### Coroutine State From 6a6aebb942971c75f90f5e1b3cf1ee884e051dd2 Mon Sep 17 00:00:00 2001 From: Chris O'Hara Date: Tue, 2 Jul 2024 07:47:42 +1000 Subject: [PATCH 4/4] Remove duplicate header --- README.md | 2 -- 1 file changed, 2 deletions(-) diff --git a/README.md b/README.md index 1388096..cb806dc 100644 --- a/README.md +++ b/README.md @@ -5,8 +5,6 @@

-# dispatch-go - [![Test](https://github.com/dispatchrun/dispatch-go/actions/workflows/test.yml/badge.svg?branch=main)](https://github.com/dispatchrun/dispatch-go/actions/workflows/test.yml) [![Go Reference](https://pkg.go.dev/badge/github.com/dispatchrun/dispatch-go.svg)](https://pkg.go.dev/github.com/dispatchrun/dispatch-go) [![Apache 2 License](https://img.shields.io/badge/license-Apache%202-blue.svg)](LICENSE)