fix #321: POSTGRES_INITDB_WALDIR handling (#324)

This is mainly to fix #321 Fix POSTGRES_INITDB_WALDIR behaviour as expected for the default setup. With added several minor improvements: * Add scenario tests for testing POSTGRES_INITDB_WALDIR possible setup * Improve README.md * Fix symlink resolution check
2021-08-19 20:55:32 +07:00 · 2021-08-19 20:55:32 +07:00 · dd9c11fdcf
commit dd9c11fdcf
--- a/.github/workflows/build-latest.yaml
+++ b/.github/workflows/build-latest.yaml
@ -14,72 +14,13 @@ on:
 #        description: Base image variant
 #        required: true
 #        default: slim
-  push:
+  workflow_dispatch:
  pull_request:
    branches:
      - develop
 jobs:
-  build-image:
-    runs-on: ubuntu-latest
-    env:
-      latest-ref: refs/heads/develop
-      defaultRepo: kartoza
-    strategy:
-      matrix:
-        postgresMajorVersion:
-          - 13
-        postgisMajorVersion:
-          - 3
-        postgisMinorRelease:
-          - 1
-        include:
-          - distro: debian
-            imageVersion: bullseye
-            imageVariant: slim
-    steps:
-      - uses: actions/checkout@v2
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v1
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v1
-      - name: Get build cache
-        uses: actions/cache@v2
-        with:
-          path: /tmp/.buildx-cache
-          # Build inputs are:
-          # - Dockerfile recipe
-          # - docker-compose.build.yml
-          # - build args (.example.env)
-          # - base_build directory
-          # - scripts directory
-          key: buildx-${{ hashFiles('Dockerfile', 'docker-compose.build.yml', '.example.env', 'base_build', 'scripts', 'scenario_tests/utils/requirements.txt') }}-${{ github.sha }}
-          restore-keys: |
-            buildx-${{ hashFiles('Dockerfile', 'docker-compose.build.yml', '.example.env', 'base_build', 'scripts', 'scenario_tests/utils/requirements.txt') }}-
-
-      - name: Build all stages
-        id: docker_build_base
-        uses: docker/build-push-action@v2
-        with:
-          context: .
-          file: Dockerfile
-          push: false
-          load: true
-          tags: ${{ secrets.DOCKERHUB_REPO || env.defaultRepo }}/postgis:base-${{ matrix.distro }}-${{ matrix.imageVersion }}-${{ matrix.imageVariant }}
-          build-args: |
-            DISTRO=${{ matrix.distro }}
-            IMAGE_VERSION=${{ matrix.imageVersion }}
-            IMAGE_VARIANT=${{ matrix.imageVariant }}
-            LANGS=en_US.UTF-8,id_ID.UTF-8
-            GENERATE_ALL_LOCALE=0
-            POSTGRES_MAJOR_VERSION=${{ matrix.postgresMajorVersion }}
-            POSTGIS_MAJOR_VERSION=${{ matrix.postgisMajorVersion }}
-            POSTGIS_MINOR_VERSION=${{ matrix.postgresMinorVersion }}
-          cache-from: type=local,src=/tmp/.buildx-cache
-          cache-to: type=local,mode=max,dest=/tmp/.buildx-cache
-
  run-scenario-tests:
    runs-on: ubuntu-latest
-    needs: [ build-image ]
    strategy:
      matrix:
        postgresMajorVersion:
@ -104,20 +45,6 @@ jobs:
        uses: docker/setup-qemu-action@v1
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v1
-      - name: Get build cache
-        uses: actions/cache@v2
-        with:
-          path: /tmp/.buildx-cache
-          # Build inputs are:
-          # - Dockerfile recipe
-          # - docker-compose.build.yml
-          # - build args (.example.env)
-          # - base_build directory
-          # - scripts directory
-          key: buildx-${{ hashFiles('Dockerfile', 'docker-compose.build.yml', '.example.env', 'base_build', 'scripts', 'scenario_tests/utils/requirements.txt') }}-${{ github.sha }}
-          restore-keys: |
-              buildx-${{ hashFiles('Dockerfile', 'docker-compose.build.yml', '.example.env', 'base_build', 'scripts', 'scenario_tests/utils/requirements.txt') }}-
-
      - name: Build image for testing
        id: docker_build_testing_image
        uses: docker/build-push-action@v2
@ -136,22 +63,25 @@ jobs:
            POSTGRES_MAJOR_VERSION=${{ matrix.postgresMajorVersion }}
            POSTGIS_MAJOR_VERSION=${{ matrix.postgisMajorVersion }}
            POSTGIS_MINOR_VERSION=${{ matrix.postgresMinorVersion }}
-          cache-from: type=local,src=/tmp/.buildx-cache
+          cache-from: |
+            type=gha,scope=test
+            type=gha,scope=prod
+            type=gha,scope=base
+          cache-to: type=gha,scope=test
          target: postgis-test

-      - name: Run scenario test
+      - name: Run scenario test ${{ matrix.scenario }}
+        working-directory: scenario_tests/${{ matrix.scenario }}
        env:
          COMPOSE_INTERACTIVE_NO_CLI: 1
          PRINT_TEST_LOGS: 1
        run: |
-          pushd scenario_tests/${{ matrix.scenario }}
-          ./test.sh
-          popd
+          bash ./test.sh

  push-internal-pr-images:
    if: github.event_name == 'pull_request' && github.event.pull_request.base.repo.url == github.event.pull_request.head.repo.url
    runs-on: ubuntu-latest
-    needs: [ build-image ]
+    needs: [ run-scenario-tests ]
    strategy:
      matrix:
        postgresMajorVersion:
@ -165,37 +95,25 @@ jobs:
            imageVersion: bullseye
            imageVariant: slim
    steps:
-      - name: Login to DockerHub
-        uses: docker/login-action@v1
-        with:
-          username: ${{ secrets.DOCKERHUB_USERNAME }}
-          password: ${{ secrets.DOCKERHUB_PASSWORD }}
-
-      - name: Docker meta
-        id: docker_meta
-        uses: crazy-max/ghaction-docker-meta@v1
-        with:
-          images: ${{ secrets.DOCKERHUB_REPO}}/postgis
-          tag-latest: false
-      
      - uses: actions/checkout@v2
      - name: Set up QEMU
        uses: docker/setup-qemu-action@v1
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v1
-      - name: Get build cache
-        uses: actions/cache@v2
+      - name: Login to DockerHub
+        uses: docker/login-action@v1
        with:
-          path: /tmp/.buildx-cache
-          # Build inputs are:
-          # - Dockerfile recipe
-          # - docker-compose.build.yml
-          # - build args (.example.env)
-          # - base_build directory
-          # - scripts directory
-          key: buildx-${{ hashFiles('Dockerfile', 'docker-compose.build.yml', '.example.env', 'base_build', 'scripts') }}-${{ github.sha }}
-          restore-keys: |
-            buildx-${{ hashFiles('Dockerfile', 'docker-compose.build.yml', '.example.env', 'base_build', 'scripts') }}-
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_PASSWORD }}
+      - name: Docker meta
+        id: docker_meta
+        uses: docker/metadata-action@v3
+        with:
+          images: ${{ secrets.DOCKERHUB_REPO}}/postgis
+          tags: |
+            type=semver,pattern=\d-\d.\d
+            type=ref,event=branch
+            type=ref,event=pr

      - name: Build image for testing
        id: docker_build_testing_image
@ -204,7 +122,8 @@ jobs:
          context: .
          file: Dockerfile
          push: true
-          tags: ${{ steps.docker_meta.outputs.tags }}-${{ matrix.postgresMajorVersion }}-${{ matrix.postgisMajorVersion }}.${{ matrix.postgisMinorRelease }}
+          tags: |
+            ${{ steps.docker_meta.outputs.tags }}-${{ matrix.postgresMajorVersion }}-${{ matrix.postgisMajorVersion }}.${{ matrix.postgisMinorRelease }}
          build-args: |
            DISTRO=${{ matrix.distro }}
            IMAGE_VERSION=${{ matrix.imageVersion }}
@ -214,5 +133,9 @@ jobs:
            POSTGRES_MAJOR_VERSION=${{ matrix.postgresMajorVersion }}
            POSTGIS_MAJOR_VERSION=${{ matrix.postgisMajorVersion }}
            POSTGIS_MINOR_VERSION=${{ matrix.postgresMinorVersion }}
-          cache-from: type=local,src=/tmp/.buildx-cache
+          cache-from: |
+            type=gha,scope=test
+            type=gha,scope=prod
+            type=gha,scope=base
+          cache-to: type=gha,scope=test
          target: postgis-test
--- a/.github/workflows/deploy-image.yaml
+++ b/.github/workflows/deploy-image.yaml
@ -44,19 +44,6 @@ jobs:
        uses: docker/setup-qemu-action@v1
      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v1
-      - name: Get build cache
-        uses: actions/cache@v2
-        with:
-          path: /tmp/.buildx-cache
-          # Build inputs are:
-          # - Dockerfile recipe
-          # - docker-compose.build.yml
-          # - build args (.example.env)
-          # - base_build directory
-          # - scripts directory
-          key: buildx-${{ hashFiles('Dockerfile', 'docker-compose.build.yml', '.example.env', 'base_build', 'scripts', 'scenario_tests/utils/requirements.txt') }}-${{ github.sha }}
-          restore-keys: |
-            buildx-${{ hashFiles('Dockerfile', 'docker-compose.build.yml', '.example.env', 'base_build', 'scripts', 'scenario_tests/utils/requirements.txt') }}-

      - name: Login to DockerHub
        uses: docker/login-action@v1
@ -82,8 +69,11 @@ jobs:
            POSTGRES_MAJOR_VERSION=${{ matrix.postgresMajorVersion }}
            POSTGIS_MAJOR_VERSION=${{ matrix.postgisMajorVersion }}
            POSTGIS_MINOR_VERSION=${{ matrix.postgresMinorVersion }}
-          cache-from: type=local,src=/tmp/.buildx-cache
-          cache-to: type=local,dest=/tmp/.buildx-cache
+          cache-from: |
+            type=gha,scope=test
+            type=gha,scope=prod
+            type=gha,scope=base
+          cache-to: type=gha,scope=base
          target: postgis-base

      - name: Build prod image
@ -105,6 +95,9 @@ jobs:
            POSTGRES_MAJOR_VERSION=${{ matrix.postgresMajorVersion }}
            POSTGIS_MAJOR_VERSION=${{ matrix.postgisMajorVersion }}
            POSTGIS_MINOR_VERSION=${{ matrix.postgresMinorVersion }}
-          cache-from: type=local,src=/tmp/.buildx-cache
-          cache-to: type=local,dest=/tmp/.buildx-cache
+          cache-from: |
+            type=gha,scope=test
+            type=gha,scope=prod
+            type=gha,scope=base
+          cache-to: type=gha,scope=prod
          target: postgis-prod
--- a/README.md
+++ b/README.md
@ -1,4 +1,5 @@
-[![Build Status](https://travis-ci.org/kartoza/docker-postgis.svg?branch=develop)](https://travis-ci.org/kartoza/docker-postgis)
+[![Scenario Tests](https://github.com/kartoza/docker-postgis/actions/workflows/build-latest.yaml/badge.svg?branch=develop&event=push)](https://github.com/kartoza/docker-postgis/actions/workflows/build-latest.yaml)
+[![deploy-image](https://github.com/kartoza/docker-postgis/actions/workflows/deploy-image.yaml/badge.svg)](https://github.com/kartoza/docker-postgis/actions/workflows/deploy-image.yaml)

 # docker-postgis

@ -143,7 +144,7 @@ You need to specify different empty directory, like this
 The containers will use above parameters to initialize a new db cluster in the
 specified directory. If the directory is not empty, then initialization parameter will be ignored.

-These are some initialization parameters that will only get used to initialize a new cluster.
+These are some initialization parameters that will only be used to initialize a new cluster.
 If the container uses an existing cluster, it is ignored (for example, when the container restarts).

 * `DEFAULT_ENCODING`: cluster encoding
@ -152,6 +153,7 @@ If the container uses an existing cluster, it is ignored (for example, when the
 * `WAL_SEGSIZE`: WAL segsize option
 * `PASSWORD_AUTHENTICATION` : PASSWORD AUTHENTICATION
 * `INITDB_EXTRA_ARGS`: extra parameter that will be passed down to `initdb` command
+* `POSTGRES_INITDB_WALDIR`: parameter to tell postgres about the initial waldir location. Note that you must always mount persistent volume to this location. Postgres will expect that the directory will always be available, even though it doesn't need the environment variable anymore. If you didn't persist this location, postgres will not be able to find the `pg_wal` directory and consider the instance to be broken.

 In addition to that, we have another parameter: `RECREATE_DATADIR` that can be used to force database reinitializations.
 If this parameter is specified as `TRUE` it will act as explicit consent to delete `DATADIR` and create
--- a/scenario_tests/datadir_init/docker-compose.yml
+++ b/scenario_tests/datadir_init/docker-compose.yml
@ -2,7 +2,10 @@ version: '2.1'
 volumes:
  default-pg-data-dir:
  new-pg-data-dir:
+  new-pg-data-dir-2:
+  new-pg-data-dir-3:
  recreate-pg-data-dir:
+  init-waldir:
 services:
  pg-default:
    image: 'kartoza/postgis:${TAG:-manual-build}'
@ -58,3 +61,83 @@ services:
      timeout: 30s
      retries: 3
      test: "pg_isready"
+  
+  pg-custom-waldir-wrong:
+    image: 'kartoza/postgis:${TAG:-manual-build}'
+    volumes:
+      # Mount to a locations where there are initial data
+      - new-pg-data-dir-2:/opt/mypostgis/data
+      # Specify different waldir location
+      - init-waldir:/opt/mypostgis/data/waldir
+      - ./tests:/tests
+      - ../utils:/lib/utils
+    environment:
+      TEST_CLASS: TestCustomWALdir
+      DATADIR: /opt/mypostgis/data
+      POSTGRES_INITDB_WALDIR: /opt/mypostgis/data/waldir
+      POSTGRES_PASS: 'docker'
+    healthcheck:
+      interval: 60s
+      timeout: 30s
+      retries: 3
+      test: "pg_isready"
+
+  pg-custom-waldir-correct:
+    image: 'kartoza/postgis:${TAG:-manual-build}'
+    volumes:
+      # Mount to new locations where there are no initial data
+      - new-pg-data-dir-3:/opt/mypostgis/data
+      # Specify different waldir location
+      - init-waldir:/opt/mypostgis/waldir
+      - ./tests:/tests
+      - ../utils:/lib/utils
+    environment:
+      TEST_CLASS: TestCustomWALdir
+      DATADIR: /opt/mypostgis/data
+      POSTGRES_INITDB_WALDIR: /opt/mypostgis/waldir
+      POSTGRES_PASS: 'docker'
+    healthcheck:
+      interval: 60s
+      timeout: 30s
+      retries: 3
+      test: "pg_isready"
+  
+  pg-custom-waldir-not-match-1:
+    image: 'kartoza/postgis:${TAG:-manual-build}'
+    volumes:
+      # Mount to a locations where there are initial data
+      - new-pg-data-dir-3:/opt/mypostgis/data
+      # Specify different waldir location
+      - init-waldir:/opt/mypostgis/waldir
+      - ./tests:/tests
+      - ../utils:/lib/utils
+    environment:
+      TEST_CLASS: TestCustomWALdirNotMatch
+      DATADIR: /opt/mypostgis/data
+      POSTGRES_INITDB_WALDIR: /opt/waldir
+      POSTGRES_PASS: 'docker'
+    healthcheck:
+      interval: 60s
+      timeout: 30s
+      retries: 3
+      test: "pg_isready"
+  
+  pg-custom-waldir-not-match-2:
+    image: 'kartoza/postgis:${TAG:-manual-build}'
+    volumes:
+      # Mount to a locations where there are initial data
+      - new-pg-data-dir-2:/opt/mypostgis/data
+      # Specify different waldir location
+      - init-waldir:/opt/waldir
+      - ./tests:/tests
+      - ../utils:/lib/utils
+    environment:
+      TEST_CLASS: TestCustomWALdirNotMatch
+      DATADIR: /opt/mypostgis/data
+      POSTGRES_INITDB_WALDIR: /opt/waldir
+      POSTGRES_PASS: 'docker'
+    healthcheck:
+      interval: 60s
+      timeout: 30s
+      retries: 3
+      test: "pg_isready"
--- a/scenario_tests/datadir_init/test.sh
+++ b/scenario_tests/datadir_init/test.sh
@ -6,7 +6,7 @@ set -e
 source ../test-env.sh

 # Run service
-docker-compose up -d
+docker-compose up -d pg-default pg-new pg-recreate

 if [[ -n "${PRINT_TEST_LOGS}" ]]; then
  docker-compose logs -f &
@ -28,4 +28,7 @@ for service in "${services[@]}"; do

 done

+# special meta test to check the setup
+bash ./test_custom_waldir.sh
+
 docker-compose down -v
--- a/scenario_tests/datadir_init/test_custom_waldir.sh
+++ b/scenario_tests/datadir_init/test_custom_waldir.sh
@ -0,0 +1,110 @@
+#!/usr/bin/env bash
+
+# exit immediately if test fails
+set -e
+
+source ../test-env.sh
+
+# This test is special
+# It is used to check the meta level of the setup.
+
+# Print logs
+if [[ -n "${PRINT_TEST_LOGS}" ]]; then
+    docker-compose logs -f &
+fi
+
+# Recreate containers with the same setup as pg-new and pg-default
+# Try to make sure that container recreation is successful
+echo "### Checking Container Recreation"
+docker-compose down
+docker-compose up -d pg-default pg-new pg-recreate
+
+sleep 60
+
+services=("pg-default" "pg-new" "pg-recreate")
+
+for service in "${services[@]}"; do
+
+    # Execute tests
+    until docker-compose exec -T $service pg_isready; do
+        sleep 5
+        echo "Wait service to be ready"
+    done;
+    echo "Execute test for $service"
+    docker-compose exec -T $service /bin/bash /tests/test.sh
+
+done
+
+# Check the wrong setup must have warned that nested custom pg_wal location
+# is prevented
+echo "### Checking Error Message on nested pg_wal location"
+service="pg-custom-waldir-wrong"
+docker-compose up -d pg-custom-waldir-wrong
+
+sleep 60
+
+# Loop until we found error message
+while true; do
+    if [[ -n "$(docker-compose logs $service | grep 'Error')" && \
+        -n "$(docker-compose logs $service | grep 'POSTGRES_INITDB_WALDIR should not be set to be inside DATADIR or PGDATA.')" ]]; then
+        break
+    fi
+    sleep 5
+done;
+
+docker-compose down
+
+# Check that the correct custom initdb waldir works, twice after container restart.
+echo "### Checking custom POSTGRES_INITDB_WALDIR should work"
+service="pg-custom-waldir-correct"
+for ((i=1;i<=2;i++)); do
+    echo "attempt $i"
+    docker-compose up -d $service
+    sleep 60
+    until docker-compose exec -T $service pg_isready; do
+        sleep 5
+        echo "Wait service to be ready"
+    done;
+    echo "Execute test for $service"
+    docker-compose exec -T $service /bin/bash /tests/test.sh
+    docker-compose down
+done
+
+# Check that if the variable POSTGRES_INITBD_WALDIR doesn't match with pg_wal symlink,
+# then give warning, but proceeds if the the mount is still correct
+echo "### Checking raise warning if custom POSTGRES_INITDB_WALDIR does not match"
+service="pg-custom-waldir-not-match-1"
+docker-compose up -d $service
+sleep 60
+# Loop until we found warning message
+while true; do
+    if [[ -n "$(docker-compose logs $service | grep 'Warning')" && \
+        -n "$(docker-compose logs $service | grep 'POSTGRES_INITDB_WALDIR is not the same as what pg_wal is pointing to.')" ]]; then
+        break
+    fi
+    sleep 5
+done;
+until docker-compose exec -T $service pg_isready; do
+    sleep 5
+    echo "Wait service to be ready"
+done;
+echo "Execute test for $service"
+docker-compose exec -T $service /bin/bash /tests/test.sh
+docker-compose down
+
+# Check that if the pg_wal is empty, then something is wrong and we should exit
+echo "### Checking Error and Exit if pg_wal is empty"
+service="pg-custom-waldir-not-match-2"
+docker-compose up -d $service
+sleep 60
+# Loop until we found warning message
+warning_text="Can't proceed because \"/opt/mypostgis/data/pg_wal\" directory is empty."
+while true; do
+    if [[ -n "$(docker-compose logs $service | grep 'Error')" && \
+        -n "$(docker-compose logs $service | grep "$warning_text")" ]]; then
+        break
+    fi
+    sleep 5
+done;
+
+docker-compose down -v
--- a/scenario_tests/datadir_init/tests/test_datadir.py
+++ b/scenario_tests/datadir_init/tests/test_datadir.py
@ -1,6 +1,7 @@
 import unittest
 import os
 from utils.utils import DBConnection
+from pathlib import Path


 class TestCollationBase(unittest.TestCase):
@ -78,3 +79,35 @@ class TestRecreate(TestCollationBase):
            self.assertEqual(dbcollate, os.environ.get('DEFAULT_COLLATION'))
            self.assertEqual(dbctype, os.environ.get('DEFAULT_CTYPE'))

+
+class TestCustomWALdir(TestCollationBase):
+
+    def test_check_pg_wal_symlink(self):
+        self.db.conn.autocommit = True
+        postgres_initdb_waldir = os.environ.get('POSTGRES_INITDB_WALDIR')
+        with self.db.cursor() as c:
+            datadir_location = self.fetch_datadir_location(c)
+            pg_wal_symlink = os.path.join(datadir_location, 'pg_wal')
+            # In this correct setup, pg_wal symlink must resolve to the 
+            # correct POSTGRES_INITDB_WALDIR location
+            self.assertTrue(
+                Path(pg_wal_symlink).resolve().match(postgres_initdb_waldir))
+
+
+class TestCustomWALdirNotMatch(TestCollationBase):
+
+    def test_check_pg_wal_symlink(self):
+        self.db.conn.autocommit = True
+        postgres_initdb_waldir = os.environ.get('POSTGRES_INITDB_WALDIR')
+        with self.db.cursor() as c:
+            datadir_location = self.fetch_datadir_location(c)
+            pg_wal_symlink = os.path.join(datadir_location, 'pg_wal')
+            # In this wrong setup, pg_wal symlink and POSTGRES_INITDB_WALDIR
+            # must resolve to a different path to raise the warning
+            self.assertFalse(
+                Path(pg_wal_symlink).resolve().match(postgres_initdb_waldir))
+
+            # It has different path, but if this unittests runs, that means
+            # postgres was able to start and the pg_wal symlink contains correct
+            # data
+            self.assertTrue(os.listdir(pg_wal_symlink))
--- a/scripts/env-data.sh
+++ b/scripts/env-data.sh
@ -3,7 +3,9 @@ POSTGRES_MAJOR_VERSION=$(cat /tmp/pg_version.txt)
 POSTGIS_MAJOR=$(cat /tmp/pg_major_version.txt)
 POSTGIS_MINOR_RELEASE=$(cat /tmp/pg_minor_version.txt)
 DEFAULT_DATADIR="/var/lib/postgresql/${POSTGRES_MAJOR_VERSION}/main"
-DEFAULT_INITDB_WALDIR="/var/lib/postgresql/${POSTGRES_MAJOR_VERSION}/pg_waldir"
+# Commented for documentation. You can specify the location of
+# pg_wal directory/volume using the following environment variable:
+# POSTGRES_INITDB_WALDIR (default value is unset)
 ROOT_CONF="/etc/postgresql/${POSTGRES_MAJOR_VERSION}/main"
 PG_ENV="$ROOT_CONF/environment"
 CONF="$ROOT_CONF/postgresql.conf"
@ -71,10 +73,6 @@ fi
 }


-if [ -z "${POSTGRES_INITDB_WALDIR}" ]; then
-	POSTGRES_INITDB_WALDIR=${DEFAULT_INITDB_WALDIR}
-fi
-
 # Make sure we have a user set up
 if [ -z "${POSTGRES_USER}" ]; then
 	POSTGRES_USER=docker
--- a/scripts/setup-database.sh
+++ b/scripts/setup-database.sh
@ -3,26 +3,76 @@
 source /scripts/env-data.sh

 POSTGRES_PASS=$(cat /tmp/PGPASSWORD.txt)
+INITDB_WALDIR_FLAG=""
+
+# Check POSTGRES_INITDB_WALDIR value
+if [[ -n "${POSTGRES_INITDB_WALDIR}" ]]; then
+    # If POSTGRES_INITDB_WALDIR is defined, make sure that it is not inside 
+    # the ${DATADIR} directory, to avoid deletions
+    case "${POSTGRES_INITDB_WALDIR}" in
+        ${DATADIR}/*)
+            # In this case, we have to fail early
+            echo "POSTGRES_INITDB_WALDIR should not be set to be inside DATADIR or PGDATA" 
+cat << EOF 1>&2
+Error!
+POSTGRES_INITDB_WALDIR should not be set to be inside DATADIR or PGDATA.
+POSTGRES_INITDB_WALDIR: ${POSTGRES_INITDB_WALDIR}
+DATADIR or PGDATA: ${DATADIR}
+EOF
+            exit 1
+            ;;
+        *)
+            # For other case, make sure the directory is created with proper permissions
+            create_dir "${POSTGRES_INITDB_WALDIR}"
+            chown -R postgres:postgres ${POSTGRES_INITDB_WALDIR}
+            ;;
+    esac
+    # Set the --waldir flag for postgres initialization
+    INITDB_WALDIR_FLAG="--waldir ${POSTGRES_INITDB_WALDIR}"
+fi

 # test if DATADIR has content
-# Do initialization if DATADIR is empty, or RECREATE_DATADIR is true
-if [[ -z "$(ls -A ${DATADIR} 2> /dev/null)" || "${RECREATE_DATADIR}" == 'TRUE' ]]; then
+# Do initialization if DATADIR directory is empty, or RECREATE_DATADIR is true
+if [[ -z "$(ls -A ${DATADIR} 2> /dev/null)" || "${RECREATE_DATADIR}" =~ [Tt][Rr][Uu][Ee] ]]; then
    # Only attempt reinitializations if ${RECREATE_DATADIR} is true
    # No Replicate From settings. Assume that this is a master database.
    # Initialise db
    echo "Initializing Postgres Database at ${DATADIR}"
-    create_dir ${POSTGRES_INITDB_WALDIR}
-    create_dir ${DATADIR}
+    create_dir "${DATADIR}"
    rm -rf ${DATADIR}/*
-    chown -R postgres:postgres ${DATADIR} ${POSTGRES_INITDB_WALDIR}
+    chown -R postgres:postgres "${DATADIR}"
    echo "Initializing with command:"
-    command="$INITDB -U postgres --pwfile=<(echo "$POSTGRES_PASS") -E ${DEFAULT_ENCODING} --lc-collate=${DEFAULT_COLLATION} --lc-ctype=${DEFAULT_CTYPE} --wal-segsize=${WAL_SEGSIZE} --auth=${PASSWORD_AUTHENTICATION} -D ${DATADIR} --waldir=${POSTGRES_INITDB_WALDIR} ${INITDB_EXTRA_ARGS}"
+    command="$INITDB -U postgres --pwfile=<(echo "$POSTGRES_PASS") -E ${DEFAULT_ENCODING} --lc-collate=${DEFAULT_COLLATION} --lc-ctype=${DEFAULT_CTYPE} --wal-segsize=${WAL_SEGSIZE} --auth=${PASSWORD_AUTHENTICATION} -D ${DATADIR} ${INITDB_WALDIR_FLAG} ${INITDB_EXTRA_ARGS}"
+    echo "$command"
    su - postgres -c "$command"
+else
+    # If using existing datadir:
+    # Check if pg_wal symlink point to the correct directory described by POSTGRES_INITDB_WALDIR.
+    # Give warning if the value is not the same
+    if [[ -n "${POSTGRES_INITDB_WALDIR}" && \
+        "$(realpath ${POSTGRES_INITDB_WALDIR})" != "$(realpath "$(readlink ${DATADIR}/pg_wal)")" ]]; then
+cat << EOF 1>&2
+Warning!
+POSTGRES_INITDB_WALDIR is not the same as what pg_wal is pointing to.
+POSTGRES_INITDB_WALDIR: ${POSTGRES_INITDB_WALDIR}
+pg_wal: $(readlink ${DATADIR}/pg_wal)
+EOF
+    fi
+
+    # Check if the pg_wal is empty.
+    # Exit the process if pg_wal is somehow empty
+    if [[ -z "$(ls -A ${DATADIR}/pg_wal 2> /dev/null)" ]]; then
+cat << EOF 1>&2
+Error!
+Can't proceed because "${DATADIR}/pg_wal" directory is empty.
+EOF
+      exit 1
+    fi
 fi;

 # Set proper permissions
 # needs to be done as root:
-create_dir ${WAL_ARCHIVE}
+create_dir "${WAL_ARCHIVE}"
 chown -R postgres:postgres ${DATADIR} ${WAL_ARCHIVE}
 chmod -R 750 ${DATADIR} ${WAL_ARCHIVE}