Update Ruby version to 4.0 and adjust related documentation (#401)

* Update Ruby version to 4.0 and adjust related documentation

* Add network check for rubygems.org accessibility in test script

* Improve network check for rubygems.org accessibility with retries and conditional gem installation

* Refactor gem installation check to use built-in bundler instead of external gem

* Add support for ruby 4.0

* Fix ruby-rails-postgres template option default

* Fix ruby template option default

* Update Ruby version in README and devcontainer configuration to 4.0-trixie

* Enhance Docker networking

* Refactor Docker Compose configuration for improved readability

* Update PostgreSQL image to latest and adjust volume path for data persistence

* Update PostgreSQL image to latest and adjust volume path for data persistence

* addressing  review comments

* addressing  review comments

* Update gem presence check for Bundler

* Update Ruby version format in devcontainer template

* Update Ruby version format in README and devcontainer templates

* Consolidate comments

Author: sireeshajonnalagadda

.devcontainer/devcontainer.json

@@ -2,7 +2,7 @@
 	"image": "mcr.microsoft.com/devcontainers/javascript-node:4-24-trixie",
 	"features": {
 		"ghcr.io/devcontainers/features/docker-in-docker:2": {
-			"moby":"false"
+			"moby": "false"
 		}
 	},
 	"postCreateCommand": "npm install -g @devcontainers/cli",

src/ruby-rails-postgres/.devcontainer/Dockerfile

@@ -1,4 +1,4 @@
-FROM mcr.microsoft.com/devcontainers/ruby:2-${templateOption:imageVariant}
+FROM mcr.microsoft.com/devcontainers/ruby:3-${templateOption:imageVariant}
 
 # Install Rails
 RUN su vscode -c "gem install rails webdrivers"

src/ruby-rails-postgres/.devcontainer/docker-compose.yml

@@ -1,4 +1,5 @@
-version: '3'
+# Dev Container Docker Compose Configuration for Ruby on Rails with PostgreSQL
+# This configuration has been optimized for reliability in automated and remote environments
 
 services:
   app:
@@ -12,17 +13,36 @@ services:
     # Overrides default command so things don't shut down after the process ends.
     command: sleep infinity
 
-    # Runs app on the same network as the database container, allows "forwardPorts" in devcontainer.json function.
-    network_mode: service:db
+    # Database connection string for Rails applications
+    # Provides a standard way to connect to the PostgreSQL database
+    environment:
+      DATABASE_URL: "postgresql://postgres:postgres@db:5432/postgres"
 
+   # Use proper Docker networking (not network_mode) to avoid namespace issues and ensure reliable container startup across environments
+    depends_on:
+      db:
+        condition: service_healthy # Wait for PostgreSQL to be ready before starting the app
+    networks:
+      - app-network # Connect to custom bridge network for service communication
     # Use "forwardPorts" in **devcontainer.json** to forward an app port locally.
     # (Adding the "ports" property to this file will not forward from a Codespace.)
 
   db:
     image: postgres:latest
     restart: unless-stopped
+    networks:
+      - app-network # Connect to the same network as the app container
+
+    # Health check ensures PostgreSQL is ready before dependent services start
+    # This is critical for depends_on with condition: service_healthy to work properly
+    healthcheck:
+      test: [ "CMD-SHELL", "pg_isready -U postgres" ]
+      interval: 10s # Check every 10 seconds
+      timeout: 5s # Wait up to 5 seconds for response
+      retries: 5 # Retry 5 times before marking as unhealthy
+      start_period: 30s # Give PostgreSQL 30 seconds to start before health checks begin
     volumes:
-      - postgres-data:/var/lib/postgresql/data
+      - postgres-data:/var/lib/postgresql
       - ./create-db-user.sql:/docker-entrypoint-initdb.d/create-db-user.sql
     environment:
       POSTGRES_USER: postgres
@@ -53,5 +73,15 @@ services:
     # Add "forwardPorts": ["5432"] to **devcontainer.json** to forward PostgreSQL locally.
     # (Adding the "ports" property to this file will not forward from a Codespace.)
 
+# Persistent storage for PostgreSQL data
 volumes:
   postgres-data:
+    # Named volume ensures data persists across container restarts
+    # Located at /var/lib/postgresql/data inside the container
+
+# Custom bridge network for service communication  
+# Replaces the problematic network_mode: service:db approach
+networks:
+  app-network:
+    driver: bridge # Standard bridge driver for container-to-container communication
+    # Services on this network can communicate using service names (app -> db)

src/ruby-rails-postgres/README.md

@@ -7,7 +7,7 @@ Develop Ruby on Rails applications with Postgres. Includes a Rails application c
 
 | Options Id | Description | Type | Default Value |
 |-----|-----|-----|-----|
-| imageVariant | Ruby version (use -trixie, -bookworm, -bullseye variants on local arm64/Apple Silicon) : | string | 3.4-trixie |
+| imageVariant | Ruby version (use -trixie, -bookworm, -bullseye variants on local arm64/Apple Silicon) : | string |4-trixie |
 
 This template references an image that was [pre-built](https://containers.dev/implementors/reference/#prebuilding) to automatically include needed devcontainer.json metadata.
 

src/ruby-rails-postgres/devcontainer-template.json

@@ -1,6 +1,6 @@
 {
     "id": "ruby-rails-postgres",
-    "version": "5.0.0",
+    "version": "6.0.0",
     "name": "Ruby on Rails & Postgres",
     "description": "Develop Ruby on Rails applications with Postgres. Includes a Rails application container and PostgreSQL server.",
     "documentationURL": "https://github.com/devcontainers/templates/tree/main/src/ruby-rails-postgres",
@@ -9,23 +9,23 @@
     "options": {
         "imageVariant": {
             "type": "string",
-            "description": "Ruby version (use -bookworm, -bullseye variants on local arm64/Apple Silicon):",
+            "description": "Ruby version (use - trixie, -bookworm, -bullseye variants on local arm64/Apple Silicon):",
             "proposals": [
-                "3-trixie",
+                "4-trixie",
                 "3.4-trixie",
                 "3.3-trixie",
                 "3.2-trixie",				
-                "3-bookworm",
+                "4-bookworm",
                 "3.4-bookworm",
                 "3.3-bookworm",
                 "3.2-bookworm",
-                "3-bullseye",
+                "4-bullseye",
                 "3.4-bullseye",				
                 "3.3-bullseye",
                 "3.2-bullseye"
             ],
-            "default": "3.4-trixie"
-        }
+			"default": "4-trixie"
+        }	
     },
     "platforms": ["Ruby"],
     "optionalPaths": [

src/ruby/.devcontainer/devcontainer.json

@@ -3,7 +3,7 @@
 {
 	"name": "Ruby",
 	// Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
-	"image": "mcr.microsoft.com/devcontainers/ruby:2-${templateOption:imageVariant}"
+	"image": "mcr.microsoft.com/devcontainers/ruby:3-${templateOption:imageVariant}"
 
 	// Features to add to the dev container. More info: https://containers.dev/features.
 	// "features": {},

src/ruby/README.md

@@ -7,7 +7,7 @@ Develop Ruby based applications. includes everything you need to get up and runn
 
 | Options Id | Description | Type | Default Value |
 |-----|-----|-----|-----|
-| imageVariant | Ruby version (use -trixie, -bookworm, -bullseye variants on local arm64/Apple Silicon) : | string | 3.4-trixie |
+| imageVariant | Ruby version (use -trixie, -bookworm, -bullseye variants on local arm64/Apple Silicon) : | string |4-trixie |
 
 This template references an image that was [pre-built](https://containers.dev/implementors/reference/#prebuilding) to automatically include needed devcontainer.json metadata.
 

src/ruby/devcontainer-template.json

@@ -1,6 +1,6 @@
 {
     "id": "ruby",
-    "version": "5.0.0",
+    "version": "6.0.0",
     "name": "Ruby",
     "description": "Develop Ruby based applications. includes everything you need to get up and running.",
     "documentationURL": "https://github.com/devcontainers/templates/tree/main/src/ruby",
@@ -11,20 +11,20 @@
             "type": "string",
             "description": "Ruby version (use -trixie, -bookworm, -bullseye variants on local arm64/Apple Silicon):",
             "proposals": [
-                "3-trixie",
+                "4-trixie",
                 "3.4-trixie",				
                 "3.3-trixie",
                 "3.2-trixie",				
-                "3-bookworm",
+                "4-bookworm",
                 "3.4-bookworm",				
                 "3.3-bookworm",
                 "3.2-bookworm",
-                "3-bullseye",
+                "4-bullseye",
                 "3.4-bullseye",				
                 "3.3-bullseye",
                 "3.2-bullseye"
             ],
-            "default": "3.4-trixie"
+            "default": "4-trixie"
         }
     },
     "platforms": ["Ruby"],

test/ruby-rails-postgres/test.sh

@@ -10,12 +10,17 @@ fixTestProjectFolderPrivs
 # Run common tests
 checkCommon
 
+
 # Run devcontainer specific tests
 check "rails" rails --version
 check "rails installation path" gem which rails
 check "user has write permission to rvm gems" [ -w /usr/local/rvm/gems ]
 check "user has write permission to rvm gems default" [ -w /usr/local/rvm/gems/default ]
 check "user can install gems" gem install github-markup
+check "gem command works" gem --version
+check "user can install gems" gem install github-markup
+check "Bundler gem presence " gem list | grep -q "bundler" 
+
 
 # Report result
 reportResults