zx script for zero downtime docker compose deployment

deploy.mjs

#!/usr/bin/env zx
const SERVICE_NAME = 'community-api-public';

const reloadNginx = () =>
  quiet($`docker compose exec nginx /usr/sbin/nginx -s reload > /dev/null`);

const trim = (promise) =>
  promise.then((result) => result.stdout).then((output) => output.trim());

const getHealthStatus = (id) =>
  trim(quiet($`docker inspect -f {{.State.Health.Status}} ${id}`));

const waitForHealthy = async (id) =>
  new Promise(async (resolve, reject) => {
    const MAX_ATTEMPTS = process.env.MAX_ATTEMPTS
      ? parseInt(process.env.MAX_ATTEMPTS)
      : 10;

    console.log(
      `Waiting for container ${id} to be healthy. Max attempts: ${MAX_ATTEMPTS}`,
    );

    let success = false;
    let attempts = 0;

    while (!success) {
      if (attempts >= MAX_ATTEMPTS) {
        return reject(
          new Error(
            `Container ${id} is not healthy after ${MAX_ATTEMPTS} attempts`,
          ),
        );
      }

      const status = await getHealthStatus(id);

      if (status === 'unhealthy') {
        return reject(new Error(`Container ${id} is unhealthy`));
      }

      if (status === 'healthy') {
        success = true;
        return resolve();
      }

      attempts++;
      await sleep(10000);
    }
  });

console.log(`Deploying service ${SERVICE_NAME}`);

const OLD_CONTAINER_ID = await trim(
  $`docker ps -f name=${SERVICE_NAME} -q | tail -n1`,
);
console.log(`Old container id: ${OLD_CONTAINER_ID}`);

console.log('Starting new container');
await $`docker-compose up -d --no-deps --scale ${SERVICE_NAME}=2 --no-recreate ${SERVICE_NAME}`;

const NEW_CONTAINER_ID = await trim(
  $`docker ps -f name=${SERVICE_NAME} -q | head -n1`,
);
console.log(`New container id: ${NEW_CONTAINER_ID}`);

await waitForHealthy(NEW_CONTAINER_ID).catch(async (err) => {
  console.error(err.message);
  await $`docker rm --force ${NEW_CONTAINER_ID}`;
  process.exit(1);
});

console.log('Container is healthy. Reloading nginx');
await reloadNginx();

console.log('Stopping old container');
await $`docker stop ${OLD_CONTAINER_ID}`;
await $`docker rm ${OLD_CONTAINER_ID}`;

console.log('Reloading nginx');
reloadNginx();

console.log('Scaling compose service down');
await $`docker-compose up -d --no-deps --scale ${SERVICE_NAME}=1 --no-recreate ${SERVICE_NAME}`;

console.log('Deployment finished');