Development Guide

​

Setting Up Metlo Locally

​

Requirements

1. node version 18.7.0. We recommend using nvm to manage node versions.
2. postgres version 14.
3. redis

​

Initial Setup

# 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:

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

cd frontend
yarn dev

2. Start the backend

cd backend
yarn dev

3. Start the collector service

cd backend
yarn dev-collector

4. Start the job scheduler

cd backend
yarn start-jobs

5. Start the analyzer

cd backend
yarn start-analyzer

You should now be able to view the metlo frontend at 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:

# 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:

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:

yarn run migration:run