matrix-docker-ansible-deploy/roles/matrix-postgres/tasks/util/detect_existing_postgres_version.yml

---

# This utility aims to determine if there is some existing Postgres version in use or not.
# If there is, it also tries to detect the Docker image that corresponds to that version.

- name: Initialize Postgres version determination variables (default to empty)
  set_fact:
    matrix_postgres_detection_pg_version_path: "{{ matrix_postgres_data_path }}/PG_VERSION"
    matrix_postgres_detected_existing: false
    matrix_postgres_detected_version: ""
    matrix_postgres_detected_version_corresponding_docker_image: ""

- name: Determine existing Postgres version (check PG_VERSION file)
  stat:
    path: "{{ matrix_postgres_detection_pg_version_path }}"
  register: result_pg_version_stat

- set_fact:
    matrix_postgres_detected_existing: true
  when: "result_pg_version_stat.stat.exists"

- name: Determine existing Postgres version (read PG_VERSION file)
  slurp:
    src: "{{ matrix_postgres_detection_pg_version_path }}"
  register: result_pg_version
  when: matrix_postgres_detected_existing|bool

- name: Determine existing Postgres version (make sense of PG_VERSION file)
  set_fact:
    matrix_postgres_detected_version: "{{ result_pg_version['content']|b64decode|replace('\n', '') }}"
  when: matrix_postgres_detected_existing|bool

- name: Determine corresponding Docker image to detected version (assume default of latest)
  set_fact:
    matrix_postgres_detected_version_corresponding_docker_image: "{{ matrix_postgres_docker_image_latest }}"
  when: "matrix_postgres_detected_version != ''"

- name: Determine corresponding Docker image to detected version (use 9.x, if detected)
  set_fact:
    matrix_postgres_detected_version_corresponding_docker_image: "{{ matrix_postgres_docker_image_v9 }}"
  when: "matrix_postgres_detected_version.startswith('9.')"

- name: Determine corresponding Docker image to detected version (use 10.x, if detected)
  set_fact:
    matrix_postgres_detected_version_corresponding_docker_image: "{{ matrix_postgres_docker_image_v10 }}"
  when: "matrix_postgres_detected_version == '10' or matrix_postgres_detected_version.startswith('10.')"