Fix Docker database startup (#360)

DOCKER_README.md

@@ -43,10 +43,14 @@ docker compose up -d
 
 This command will:
 - Build the TravianZ web application container
-- Start a MariaDB (latest) database container
+- Start a MariaDB (latest) database container and wait for it to become ready
-- Start a phpMyAdmin container for database management
+- Start the web application and phpMyAdmin after MariaDB is healthy
 - Set up a network for all containers to communicate
 
+The installation wizard creates the TravianZ schema. SQL files in `var/db`
+are templates whose placeholders are resolved by the installer; MariaDB does
+not execute them directly during container initialization.
+
 ### 4. Access the Installation Wizard
 
 Once the containers are running, open your browser and navigate to:

docker-compose.yml

@@ -11,7 +11,8 @@ services:
     environment:
       - APACHE_DOCUMENT_ROOT=/var/www/html
     depends_on:
-      - db
+      db:
+        condition: service_healthy
     networks:
       - travianz-network
     restart: unless-stopped
@@ -26,13 +27,18 @@ services:
       MARIADB_PASSWORD: ${MARIADB_PASSWORD:-${MYSQL_PASSWORD:-travianzpass}}
     volumes:
       - db-data:/var/lib/mysql
-      - ./var/db:/docker-entrypoint-initdb.d:ro
     ports:
       - "3306:3306"
     networks:
       - travianz-network
     restart: unless-stopped
     command: --sql_mode=""
+    healthcheck:
+      test: ["CMD", "healthcheck.sh", "--connect", "--innodb_initialized"]
+      interval: 10s
+      timeout: 5s
+      retries: 10
+      start_period: 10s
 
   phpmyadmin:
     image: phpmyadmin/phpmyadmin:latest
@@ -45,7 +51,8 @@ services:
     ports:
       - "8081:80"
     depends_on:
-      - db
+      db:
+        condition: service_healthy
     networks:
       - travianz-network
     restart: unless-stopped

tests/docker-compose-contract.sh

@@ -0,0 +1,91 @@
+#!/bin/sh
+set -eu
+
+script_dir=$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)
+repo_root=$(CDPATH= cd -- "$script_dir/.." && pwd)
+compose_file=${1:-"$repo_root/docker-compose.yml"}
+
+fail()
+{
+    printf 'FAIL: %s\n' "$1" >&2
+    exit 1
+}
+
+[ -f "$compose_file" ] || fail "Compose file not found: $compose_file"
+
+if awk '
+    /^[[:space:]]*#/ { next }
+    index($0, "./var/db") && index($0, "/docker-entrypoint-initdb.d") { found = 1 }
+    END { exit found ? 0 : 1 }
+' "$compose_file"
+then
+    fail "installer SQL templates must not be mounted into /docker-entrypoint-initdb.d"
+fi
+
+if ! awk '
+    $0 == "  db:" {
+        in_db = 1
+        next
+    }
+    in_db && /^  [[:alnum:]_-]+:$/ {
+        in_db = 0
+    }
+    in_db && $0 == "    healthcheck:" {
+        healthcheck = 1
+    }
+    in_db && /healthcheck[.]sh/ && /--connect/ && /--innodb_initialized/ {
+        readiness_probe = 1
+    }
+    in_db && $0 ~ /^      interval:/ {
+        interval = 1
+    }
+    in_db && $0 ~ /^      timeout:/ {
+        timeout = 1
+    }
+    in_db && $0 ~ /^      retries:/ {
+        retries = 1
+    }
+    END {
+        exit (healthcheck && readiness_probe && interval && timeout && retries) ? 0 : 1
+    }
+' "$compose_file"
+then
+    fail "db service must define a bounded MariaDB readiness healthcheck"
+fi
+
+require_healthy_db_dependency()
+{
+    service=$1
+
+    if ! awk -v service="$service" '
+        $0 == "  " service ":" {
+            in_service = 1
+            next
+        }
+        in_service && /^  [[:alnum:]_-]+:$/ {
+            in_service = 0
+        }
+        in_service && $0 == "    depends_on:" {
+            in_dependencies = 1
+            next
+        }
+        in_service && in_dependencies && $0 == "      db:" {
+            in_db_dependency = 1
+            next
+        }
+        in_service && in_db_dependency && $0 == "        condition: service_healthy" {
+            found = 1
+        }
+        END {
+            exit found ? 0 : 1
+        }
+    ' "$compose_file"
+    then
+        fail "$service must wait for the db service to become healthy"
+    fi
+}
+
+require_healthy_db_dependency web
+require_healthy_db_dependency phpmyadmin
+
+printf 'PASS: Docker Compose database initialization contract\n'