update release drafter install command, move compose.yaml to deploy/d…

…ocker-compose, create deploy/docker-compose.env to allow image overriding

.github/release-drafter.yml

@@ -41,5 +41,5 @@ template: |
 
   ## Install from the command line
   ```sh
-  docker pull ghcr.io/$OWNER/$REPOSITORY:v$RESOLVED_VERSION
+  DEMOAPP_BACKEND_IMAGE="ghcr.io/$OWNER/$REPOSITORY:v$RESOLVED_VERSION" docker compose --project-directory deploy/docker-compose u
   ```

README.md

@@ -103,11 +103,12 @@ services:
       - "8080:8080" # Forwards container port 8080 to host port 8080. URL: http://localhost:8080/. Actuator URL: http://localhost:8080/actuator/health
 ```
 ```sh
-docker-compose up # builds application image when it doesn't exist
-docker-compose up --build # rebuild application image
-docker-compose down # remove containers, networks and volumes created by docker compose
+# Note: by default, compose.yaml was configured to use an existing application image. Run build before docker compose or update compose.yaml and enable `build` field
+
+docker compose --project-directory deploy/docker-compose up
+docker compose --project-directory deploy/docker-compose up --build # rebuild application image, only applicable if `build` field is enabled
+docker compose --project-directory deploy/docker-compose down # remove containers, networks and volumes created by docker compose
 
-# Note: by default, compose.yaml was configured to use an existing application image. Run build before docker-compose or update compose.yaml and enable `build` field
 ```
 
 ## Testing Application Container Image with Container Structure Tests

deploy/docker-compose/.env

@@ -0,0 +1,6 @@
+DEMOAPP_BACKEND_IMAGE="demoapp-backend:latest"    # locally built image
+MYSQL_IMAGE="mysql:8.0"    # https://hub.docker.com/_/mysql
+MYSQL_ROOT_PASSWORD="local"
+MYSQL_DATABASE="demoapp"
+MYSQL_USER="user"
+MYSQL_PASSWORD="password"

compose.yaml → deploy/docker-compose/compose.yaml

@@ -2,15 +2,15 @@
 # Service top-level element reference: https://docs.docker.com/compose/compose-file/05-services/
 services:
   mysql:    # Service name is also used as hostname when connecting from other containers
-    image: mysql:8.0    # https://hub.docker.com/_/mysql
+    image: ${MYSQL_IMAGE}    # use image specified in .env file
     # Docker Hub mysql image already exposes port 3306, thus `expose` keyword can be omitted
     # expose:
     #   - "3306"
     environment:
-      MYSQL_ROOT_PASSWORD: local
-      MYSQL_DATABASE: demoapp
-      MYSQL_USER: user
-      MYSQL_PASSWORD: password
+      MYSQL_ROOT_PASSWORD: ${MYSQL_ROOT_PASSWORD}
+      MYSQL_DATABASE: ${MYSQL_DATABASE}
+      MYSQL_USER: ${MYSQL_USER}
+      MYSQL_PASSWORD: ${MYSQL_PASSWORD}
     healthcheck:
       # Login to mysql demoapp db
       test: mysql --host=localhost --user=root --password=$$MYSQL_ROOT_PASSWORD demoapp    # command for testing health
@@ -31,15 +31,15 @@ services:
     depends_on:
       mysql:
         condition: service_healthy    # healthy status is indicated by `healthcheck` keyword
-    image: demoapp-backend:latest    # use built image
+    image: ${DEMOAPP_BACKEND_IMAGE}    # use image specified in .env file
     # Build image from Containerfile
     # build:
     #   context: .
     #   dockerfile: Containerfile.multistage
     environment:
       # Externalized Spring Configuration: https://docs.spring.io/spring-boot/docs/1.5.6.RELEASE/reference/html/boot-features-external-config.html
       SPRING_DATASOURCE_USERNAME: root
-      SPRING_DATASOURCE_PASSWORD: local
+      SPRING_DATASOURCE_PASSWORD: ${MYSQL_ROOT_PASSWORD}
     healthcheck:
       # Check Spring Boot Actuator
       test: curl --fail http://localhost:8080/actuator/health    # command for testing health