migrator: codeinsights-db cannot be migrated without other databases configured

Created by: danieldides

Environment

Minimal docker-compose.yaml to test with:

version: '2.4'
services:
  migrator:
    container_name: migrator
    image: 'index.docker.io/sourcegraph/migrator:3.35.1'
    cpus: 4
    mem_limit: '8g'
    command:
      ["up"]
    environment:
      - PGHOST=pgsql
      - PGPORT=5432
      - PGUSER=sg
      - PGPASSWORD=sg
      - PGDATABASE=sg
      - PGSSLMODE=disable

      - CODEINTEL_PGHOST=codeintel-db
      - CODEINTEL_PGPORT=5432
      - CODEINTEL_PGUSER=sg
      - CODEINTEL_PGPASSWORD=sg
      - CODEINTEL_PGDATABASE=sg
      - CODEINTEL_PGSSLMODE=disable

      - CODEINSIGHTS_PGHOST=codeinsights-db
      - CODEINSIGHTS_PGPORT=5432
      - CODEINSIGHTS_PGUSER=postgres
      - CODEINSIGHTS_PGPASSWORD=password
      - CODEINSIGHTS_PGDATABASE=postgres
      - CODEINSIGHTS_PGSSLMODE=disable
    restart: "on-failure"
    networks: 
      - sourcegraph
    depends_on:
      pgsql:
        condition: service_healthy
      codeintel-db:
        condition: service_healthy

  pgsql:
    container_name: pgsql
    image: 'index.docker.io/sourcegraph/postgres-12.6-alpine:insiders@sha256:695eaa5070a879863597b077c610129685a7ab4e8ac0039864b7aad3dfc5cf5b'
    cpus: 4
    mem_limit: '2g'
    healthcheck:
      test: '/liveness.sh'
      interval: 10s
      timeout: 1s
      retries: 10
      start_period: 15s
    volumes:
      - 'pgsql:/data/'
    networks:
      - sourcegraph
    restart: always
    stop_grace_period: 120s

  codeintel-db:
    container_name: codeintel-db
    image: 'index.docker.io/sourcegraph/codeintel-db:insiders@sha256:a525705803fc787d20aed15e74c739bbfb77eed4351cbb6d1a46edc89877319b'
    cpus: 4
    mem_limit: '2g'
    healthcheck:
      test: '/liveness.sh'
      interval: 10s
      timeout: 1s
      retries: 10
      start_period: 15s
    volumes:
      - 'codeintel-db:/data/'
    networks:
      - sourcegraph
    restart: always
    stop_grace_period: 120s

  codeinsights-db:
    container_name: codeinsights-db
    image: "index.docker.io/sourcegraph/codeinsights-db:insiders@sha256:56596dff34785b950fe69bcf051cbd2b7cd47fbc8d9733e8fd8af180047cdcb8"
    cpus: 4
    mem_limit: "2g"
    environment:
      - POSTGRES_PASSWORD=password
      - PGDATA=/var/lib/postgresql/data/pgdata
    volumes:
      - "codeinsights-db:/var/lib/postgresql/data/"
    networks:
      - sourcegraph
    restart: always
    stop_grace_period: 120s

volumes:
  pgsql:
  codeintel-db:
  codeinsights-db:
networks:
  sourcegraph:

Run with: docker compose -f /path/to/file.yaml up and down with docker compose -f /path/to/file.yaml -v down --remove-orphans to reset between tests.

Migrating frontend only:

Commenting out the CODEINTEL_ and CODEINSIGHTS_ env vars and changing the command to ["up", "-db", "frontend"] yields:

migrator         | t=2022-01-21T00:21:11+0000 lvl=info msg="Checked current version" schema=frontend version=1528395964 dirty=false
migrator         | t=2022-01-21T00:21:11+0000 lvl=info msg="Checked current version" schema=frontend version=1528395964 dirty=false
migrator         | t=2022-01-21T00:21:11+0000 lvl=info msg="Upgrading schema" schema=frontend
migrator exited with code 0

where the migrator starts and migrates the frontend alone.

Migrating codeinsights only:

Commenting out PG_ and CODEINTEL_ env vars and changing the command to ["up", "-db", "codeinsights"] yields:

migrator         | error: frontend and codeintel databases must be distinct: postgres://[email protected]:5432 and postgres://[email protected]:5432 seem to refer to the same database
migrator exited with code 1

If you add back in all three sets of env vars, it starts and succeeds as expected. It does not appear to make a connection (the values can invalid) but it needs them set to be able to identify that the connection strings are different.