> ## Documentation Index
> Fetch the complete documentation index at: https://docs.metlo.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Development Guide

### Setting Up Metlo Locally

#### Requirements

1. `node` version `18.7.0`. We recommend using
   [nvm](https://github.com/nvm-sh/nvm) to manage node versions.
2. `postgres` version `14`.
3. `redis`

#### Initial Setup

```bash Bash theme={null}
# Clone Metlo
git clone https://github.com/metlo-labs/metlo.git
cd metlo

# Install Yarn
npm i -g yarn

# Create a test database
psql postgres://localhost:5432/postgres -c "CREATE DATABASE metlo_api_security;"

# Build the common modules
cd common
yarn install && yarn build

# Install npm packages for the frontend and backend
cd ../frontend
yarn
cd ../backend
yarn
yarn run migration:run
yarn build
```

#### Set up environment

Create `.env` file in backend directory with the following environment
variables:

```
DB_URL=<DB_CONNECTION_URL>
ENCRYPTION_KEY=<ENCRYPTION_KEY>
EXPRESS_SECRET="some_random_string"
```

To generate the `ENCRYPTION_KEY` run this python script:

```py Python theme={null}
import secrets
from base64 import b64encode

print(b64encode(secrets.token_bytes(32)).decode("UTF-8"))
```

#### Start Services

Finally, you can start each service in a different terminal window:

**1. Start the frontend**

```bash Bash theme={null}
cd frontend
yarn dev
```

**2. Start the backend**

```bash Bash theme={null}
cd backend
yarn dev
```

**3. Start the collector service**

```bash Bash theme={null}
cd backend
yarn dev-collector
```

**4. Start the job scheduler**

```bash Bash theme={null}
cd backend
yarn start-jobs
```

**5. Start the analyzer**

```bash Bash theme={null}
cd backend
yarn start-analyzer
```

<Warning>
  Job Scheduler and Analyzer

  For changes in the backend to take effect in the Job Scheduler and Analyzer, the
  backend module must be rebuilt and the Job Scheduler and Analyzer must be
  restarted.
</Warning>

You should now be able to view the metlo frontend at
[http://localhost:3000](http://localhost:3000) !

#### Load test data

Without any trace data your Metlo dashboard won't be very interesting! You can
load test trace data by running the test ingestor:

```bash Bash theme={null}
# Get an API Key from the backend
curl -X POST 'http://localhost:3000/api/v1/keys/create' -H 'Content-Type: application/json' -d '{"name":"test-api-key"}'
{"apiKey":"<YOUR_API_KEY>"}

# Start the test ingestor
cd ingestors/test_data
virtualenv --python=python3 env
source env/bin/activate
pip install -r requirements.txt
python main.py -b http://localhost:8081 -key <YOUR_API_KEY>
```

#### Migrations

To add any changes to the database schema, you must create a migration. To
create a new migration, run this command in the root of the backend directory:

```bash Bash theme={null}
yarn run migration:create ./src/migrations/<MIGRATION_DESCRIPTION>
```

Running this command will add a new file to the `migrations` directory to which
you will need to add queries to run for the migration. Afterwards, you will need
to add the new migration class to the `migrations` array in the `AppDataSource`
constructor options in the `backend/src/data-source.ts` file. To run any new
migrations, you can run this command:

```bash Bash theme={null}
yarn run migration:run
```