Monitor Postgres

[nicnocquee]

As mentioned in this discussion, it'd be great if Monika can also check if a postgres is running. Maybe using this function:

const { Client } = require('pg')
const client = new Client({
  host: 'my.database-server.com',
  port: 5334,
  user: 'database-user',
  password: 'secretpassword!!',
})
client.connect(err => {
  if (err) {
    console.error('connection error', err.stack)
  } else {
    console.log('connected')
  }
})

probes:
  - id: 'check-redis'
    postgres:
      host: '<hostname>'
      port: <port>
      password: '<password>'
      user: <user>

Just like tcp and ping probing that we already have, user doesn't need to define any alerts for the postgres checking.

So, todo:

• [ ] Monitor Postgres, send notification when it cannot be reached after reaching threshold.
• [ ] Update monika-config-schema.json to include the new properties.
• [ ] Add in the documentation.