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Getting Started with GraphQL

Installing the Tailcall CLI

You can install the latest version - by using NPM.

NPM

  1. If you don't already have nodejs installed, you can find the instructions here.

  2. Install Tailcall by running the following command in your terminal:

    npm i -g @tailcallhq/tailcall
  3. To verify the correct installation of Tailcall, run:

    tailcall
    note

    Do not use the --force flag during npm installations, as it ignores installing platform-specific builds.

Yarn

  1. Install Tailcall by running the following command in your terminal:

    yarn global add @tailcallhq/tailcall
  2. To verify the correct installation of Tailcall, run:

    tailcall

Homebrew

  1. If you don't already have Homebrew installed, you can find the instructions here.

  2. Add the Tailcall repository to Homebrew by running the following command in your terminal:

    brew tap tailcallhq/tailcall
    brew install tailcall
  3. To verify the correct installation of Tailcall, run:

    tailcall
  4. After completing the installation, perform upgrades with:

    brew update
    brew upgrade tailcall

Curl

Follow the steps below to manually install the cli on your system:

curl -sSL https://tailcall.run/install.sh | bash -s -- 

This command fetches and executes the Tailcall installation script. The ~/.tailcall directory contains the installed files.

Upon completion of the installation, extend your PATH environment variable to include the ~/.tailcall/bin directory:

# export PATH=$PATH:~/.tailcall/bin

Docker

To install Tailcall with Docker, follow the steps below. Please note that currently, this installation method only works on Linux/amd64 systems. Before starting, make sure you have Docker installed on your system. If not, download it from here.

  1. Pull the latest Tailcall Docker image using the following command:

    docker pull tailcall.docker.scarf.sh/tailcallhq/tailcall/tc-server:

    This command fetches the latest version of the Tailcall Docker image from the Docker registry.

  2. Run the Tailcall Docker container with the following command:

    docker run -d --name graphql-server -p 8000:8000 \ -v /path/to/your/configs:/etc/tailcall \ --entrypoint "/bin/sh"
    ghcr.io/tailcallhq/tailcall/tc-server: \ -c "export PATH=$PATH:~/.tailcall/bin && tailcall start /etc/tailcall/config.graphql"

    This command launches the GraphQL server in a Docker container, exposing the GraphQL endpoint on port 8080.

Configuration

Writing a GraphQL Configuration

For our first example, we are going to compose a GraphQL schema from the REST APIs at https://jsonplaceholder.typicode.com, a free online REST API with some fake data. We will use the API at /users to get a list of users, and /users/:id/posts to get the posts for each user, and compose them into a single GraphQL schema.

We can use the following formats to define our GraphQL schema: .graphql, .yml, .json.

Create one of the following files and paste the contents into it.

schema
# Specify server configuration: Start GraphQL server at 0.0.0.0:8000
@server(port: 8000)

# Specify a base url for all http requests

@upstream(baseURL: "http://jsonplaceholder.typicode.com") {

query: Query
}

type Query {

# Specify the http path for the users query

users: [User] @http(path: "/users")
}

# Create a user type with the fields returned by the users api

type User {
id: Int!
name: String!
username: String!
email: String!

# Extend the user type with the posts field

# Use the current user's id to construct the path

posts: [Post] @http(path: "/users/{{.value.id}}/posts")
}

# Create a post type with the fields returned by the posts api

type Post {
id: Int!
title: String!
body: String!
}

The above file is a standard .graphQL file, with some minor additions such as @upstream and @http directives. Basically we specify the GraphQL schema and how to resolve that GraphQL schema in the same file, without having to write any code!

Starting the GraphQL server

Now, run the following command to start the server with the full path to the file that you created earlier.

tailcall start ./jsonplaceholder.graphql

If the command succeeds, you should see logs like the following below.

INFO File read: ./jsonplaceholder.graphql ... ok
INFO N + 1 detected: 0
INFO 🚀 Tailcall launched at [0.0.0.0:8000] over HTTP/1.1
INFO 🌍 Playground: https://tailcall.run/playground/?u=http://127.0.0.1:8000/graphql

The server starts with the schema provided and prints out a load of meta information. We will cover those in detail in a bit. For now, open the playground URL in a new tab in your browser and try it out for yourself!

Making GraphQL requests to the server

  1. Open a web browser and go to https://tailcall.run/playground/?u=http://127.0.0.1:8000/graphql. This should load the GraphiQL interface.

  2. In the query editor of GraphiQL, enter the following query

    query {
    users {
    id
    name
    posts {
    title
    }
    }
    }
  3. After running the query in GraphiQL, expect to see a JSON response structured like this:

    {
    "data": {
    "users": [
    {
    "id": 1,
    "name": "Leanne Graham",
    "posts": [
    {
    "title": "sunt aut facere repellat provident occaecati excepturi option reprehenderit"
    }
    // Posts truncated for brevity
    ]
    },
    {
    "id": 2,
    "name": "Ervin Howell",
    "posts": [
    {
    "title": "et ea vero quia laudantium autem"
    },
    {
    "title": "in quibusdam tempore odit est dolorem"
    }
    // Posts truncated for brevity
    ]
    }
    // Users truncated for brevity
    ]
    }
    }

You can now add more fields, and compose more queries together!