> ## Documentation Index
> Fetch the complete documentation index at: https://wundergraphinc-brendan-add-sof-link.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.
# From Zero to Federation in 5 Steps using Cosmo
> This tutorial offers a hands-on introduction to Cosmo using a sample demo repository. You'll set up the demo subgraphs and Cosmo Router locally, allowing you to start querying right away.
### Prerequisites
## Project setup
Clone the example project, which includes two subgraphs (`Posts` and `Users`) as well as a Router.
The example project is available here: [https://github.com/wundergraph/cosmo-demo](https://github.com/wundergraph/cosmo-demo), or you can clone it with the following command:
```bash theme={null}
git clone https://github.com/wundergraph/cosmo-demo.git
cd cosmo-demo
```
### Step 1: Install the Cosmo CLI tool
Install the latest version of the Cosmo CLI.
```bash theme={null}
npm i -g wgc@latest
```
### Step 2: Set Up and Run the Subgraphs
The cloned project contains preconfigured subgraphs and a script to run them.
#### **Ensure the script is executable**
In the project's **root directory**, run this to ensure the `start-subgraphs.sh` script is executable:
```bash theme={null}
chmod +x start-subgraphs.sh
```
#### **Start the subgraphs**
Run the following command to install dependencies and start the subgraphs in the background:
```bash theme={null}
./start-subgraphs.sh
```
#### **Verify the subgraphs are running**
Once the script finishes, check the subgraphs are running by visiting:
(for `subgraph-posts`)
(for `subgraph-users`)
If both load correctly, the servers are running.
#### **Test Queries**
You can run the following queries to confirm the subgraphs are functioning correctly.
#### **Posts Subgraph (localhost:4001)**
**To retrieve all posts, run the following query:**
```bash theme={null}
query {
posts {
id
content
authorId
}
}
```
**Expected Output:**
```json theme={null}
{
"data": {
"posts": [
{
"id": "1",
"content": "Sample content",
"authorId": "user-1"
},
{
"id": "2",
"content": "Some more sample content",
"authorId": "user-1"
},
{
"id": "3",
"content": "Quality content",
"authorId": "user-2"
}
]
}
}
```
**To retrieve a single post using its** `id`**, run the following query:**
```bash theme={null}
query {
post(id: "1") {
id
content
authorId
}
}
```
**Expected Output:**
```json theme={null}
{
"data": {
"post": {
"id": "1",
"content": "Sample content",
"authorId": "user-1"
}
}
}
```
#### **Users Subgraph (localhost:4002)**
**To retrieve all users, run the following query:**
```bash theme={null}
query {
users {
id
name
}
}
```
**Expected Output:**
```json theme={null}
{
"data": {
"users": [
{
"id": "user-1",
"name": "Jane Doe"
},
{
"id": "user-2",
"name": "John Doe"
}
]
}
}
```
**To retrieve a single user with their** `id`**, run the following query:**
```bash theme={null}
query {
user(id: "user-1") {
id
name
}
}
```
**Expected Output:**
```json theme={null}
{
"data": {
"user": {
"id": "user-1",
"name": "Jane Doe"
}
}
}
```
#### **Stop the Subgraphs**
You will need to keep the script running in the background for this tutorial, but if it is necessary to stop it, run:
```bash theme={null}
pkill -f "npm run dev"
```
### Step 3: Generate the Router Configuration
The repository includes a `graph.localhost.yaml` configuration file for the `wgc` CLI tool to introspect and generate a router configuration.
#### Setup Considerations
* For Docker-based subgraphs, use `graph.yaml` instead of `graph.localhost.yaml`.
* For custom subgraphs, update the configuration file to match your setup.
#### Generate the Router Configuration
Open a new terminal and run the following command to navigate to the `router` directory.
```bash theme={null}
cd router
```
Then, generate the router configuration by running:
```bash theme={null}
wgc router compose --input graph.localhost.yaml --out config.json
```
**Expected Output**:
```bash theme={null}
Router config successfully written to config.json
```
### Step 4: Run the router
While still in the `router` directory, start the router using Docker. Make sure Docker is running on your machine before proceeding.
We recommend using Docker to prevent dependency conflicts and maintain a consistent environment.
```bash theme={null}
docker run \
--name cosmo-router \
--rm \
-p 3002:3002 \
--add-host=host.docker.internal:host-gateway \
--platform=linux/amd64 \
-e pull=always \
-e DEV_MODE=true \
-e LISTEN_ADDR=0.0.0.0:3002 \
-e EXECUTION_CONFIG_FILE_PATH="/config/config.json" \
-v "$(pwd)/config.json:/config/config.json" \
ghcr.io/wundergraph/cosmo/router:latest
```
The router will now be running in a Docker container.
### Step 5: Query Against Your Router
Now that the router is running, you can test it by running queries on your federated graph at [http://localhost:3002](http://localhost:3002).
**Get All Posts with Author Details**
```bash theme={null}
query {
posts {
id
content
author {
id
name
}
}
}
```
**Expected Output:**
```json theme={null}
{
"data": {
"posts": [
{
"id": "1",
"content": "Sample content",
"author": {
"id": "user-1",
"name": "Jane Doe"
}
},
{
"id": "2",
"content": "Some more sample content",
"author": {
"id": "user-1",
"name": "Jane Doe"
}
},
{
"id": "3",
"content": "Quality content",
"author": {
"id": "user-2",
"name": "John Doe"
}
}
]
},
"extensions": { /* omitted for brevity */ }
```
**Get a Single Post with Author Details**
```bash theme={null}
query {
post(id: "1") {
id
content
author {
id
name
}
}
}
```
**Expected Output:**
```json theme={null}
{
"data": {
"post": {
"id": "1",
"content": "Sample content",
"author": {
"id": "user-1",
"name": "Jane Doe"
}
}
},
"extensions": { /* omitted for brevity */ }
```
### All done!
Congrats! You've deployed two subgraphs, composed them into a federated Graph, and deployed a Router.
Next, consider deploying to the cloud to enable features like metrics, tracing, and monitoring in Cosmo Studio.
## Next Steps: Cosmo Cloud and deployments