.gitignore

@@ -41,3 +41,6 @@ npm-debug.log
 .env
 
 .elixir_ls/
+
+# Docker secrets directory (generated by `just init-secrets`)
+/secrets/

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - CopyToClipboard JavaScript hook with fallback for older browsers
   - Button shows count of visible selected members (respects search/filter)
   - German/English translations
+- Docker secrets support via `_FILE` environment variables for all sensitive configuration (SECRET_KEY_BASE, TOKEN_SIGNING_SECRET, OIDC_CLIENT_SECRET, DATABASE_URL, DATABASE_PASSWORD)
 
 ### Fixed
 - Email validation false positive when linking user and member with identical emails (#168 Problem #4)

Justfile

@@ -90,4 +90,27 @@ clean:
 remove-gettext-conflicts:
   #!/usr/bin/env bash
   set -euo pipefail
-  find priv/gettext -type f -exec sed -i '/^<<<<<<< HEAD$/d; /^=======$/d; /^>>>>>>>/d' {} \;
+  find priv/gettext -type f -exec sed -i '/^<<<<<<< HEAD$/d; /^=======$/d; /^>>>>>>>/d' {} \;
+
+# Production environment commands
+# ================================
+
+# Initialize secrets directory with generated secrets (only if not exists)
+init-prod-secrets:
+  #!/usr/bin/env bash
+  set -euo pipefail
+  if [ -d "secrets" ]; then
+    echo "Secrets directory already exists. Skipping generation."
+    exit 0
+  fi
+  echo "Creating secrets directory and generating secrets..."
+  mkdir -p secrets
+  mix phx.gen.secret > secrets/secret_key_base.txt
+  mix phx.gen.secret > secrets/token_signing_secret.txt
+  openssl rand -base64 32 | tr -d '\n' > secrets/db_password.txt
+  touch secrets/oidc_client_secret.txt
+  echo "Secrets generated in ./secrets/"
+
+# Start production environment with Docker Compose
+start-prod: init-prod-secrets
+  docker compose -f docker-compose.prod.yml up -d

README.md

@@ -217,6 +217,13 @@ For testing the production Docker build locally:
    # OIDC_BASE_URL=http://localhost:8080/auth/v1
    # OIDC_REDIRECT_URI=http://localhost:4001/auth/user/rauthy/callback
    # OIDC_CLIENT_SECRET=<from-rauthy-client>
+   
+   # Alternative: Use _FILE variables for Docker secrets (takes priority over regular vars):
+   # SECRET_KEY_BASE_FILE=/run/secrets/secret_key_base
+   # TOKEN_SIGNING_SECRET_FILE=/run/secrets/token_signing_secret
+   # OIDC_CLIENT_SECRET_FILE=/run/secrets/oidc_client_secret
+   # DATABASE_URL_FILE=/run/secrets/database_url
+   # DATABASE_PASSWORD_FILE=/run/secrets/database_password
    ```
 
 3. **Start development environment** (for Rauthy):
@@ -250,7 +257,7 @@ For actual production deployment:
    - Set `OIDC_BASE_URL` to your production OIDC provider
    - Configure proper Docker networks
 3. **Set up SSL/TLS** (e.g., via reverse proxy like Nginx/Traefik)
-4. **Use secure secrets management** (environment variables, Docker secrets, vault)
+4. **Use secure secrets management** — All sensitive environment variables support a `_FILE` suffix for Docker secrets (e.g., `SECRET_KEY_BASE_FILE=/run/secrets/secret_key_base`). See `docker-compose.prod.yml` for an example setup with Docker secrets.
 5. **Configure database backups**
 
 

config/runtime.exs

@@ -7,6 +7,75 @@ import Config
 # any compile-time configuration in here, as it won't be applied.
 # The block below contains prod specific runtime configuration.
 
+# Helper function to read environment variables with Docker secrets support.
+# Supports the _FILE suffix pattern: if VAR_FILE is set, reads the value from
+# that file path. Otherwise falls back to VAR directly.
+# VAR_FILE takes priority and must contain the full absolute path to the secret file.
+get_env_or_file = fn var_name, default ->
+  file_var = "#{var_name}_FILE"
+
+  case System.get_env(file_var) do
+    nil ->
+      System.get_env(var_name, default)
+
+    file_path ->
+      case File.read(file_path) do
+        {:ok, content} ->
+          String.trim_trailing(content)
+
+        {:error, reason} ->
+          raise """
+          Failed to read secret from file specified in #{file_var}="#{file_path}".
+          Error: #{inspect(reason)}
+          """
+      end
+  end
+end
+
+# Same as get_env_or_file but raises if the value is not set
+get_env_or_file! = fn var_name, error_message ->
+  case get_env_or_file.(var_name, nil) do
+    nil -> raise error_message
+    value -> value
+  end
+end
+
+# Build database URL from individual components or use DATABASE_URL directly.
+# Supports both approaches:
+# 1. DATABASE_URL (or DATABASE_URL_FILE) - full connection URL
+# 2. Separate vars: DATABASE_HOST, DATABASE_USER, DATABASE_PASSWORD (or _FILE), DATABASE_NAME, DATABASE_PORT
+build_database_url = fn ->
+  case get_env_or_file.("DATABASE_URL", nil) do
+    nil ->
+      # Build URL from separate components
+      host =
+        System.get_env("DATABASE_HOST") ||
+          raise "DATABASE_HOST is required when DATABASE_URL is not set"
+
+      user =
+        System.get_env("DATABASE_USER") ||
+          raise "DATABASE_USER is required when DATABASE_URL is not set"
+
+      password =
+        get_env_or_file!.("DATABASE_PASSWORD", """
+        DATABASE_PASSWORD or DATABASE_PASSWORD_FILE is required when DATABASE_URL is not set.
+        """)
+
+      database =
+        System.get_env("DATABASE_NAME") ||
+          raise "DATABASE_NAME is required when DATABASE_URL is not set"
+
+      port = System.get_env("DATABASE_PORT", "5432")
+
+      # URL-encode the password to handle special characters
+      encoded_password = URI.encode_www_form(password)
+      "ecto://#{user}:#{encoded_password}@#{host}:#{port}/#{database}"
+
+    url ->
+      url
+  end
+end
+
 # ## Using releases
 #
 # If you use `mix release`, you need to explicitly enable the server
@@ -21,12 +90,7 @@ if System.get_env("PHX_SERVER") do
 end
 
 if config_env() == :prod do
-  database_url =
-    System.get_env("DATABASE_URL") ||
-      raise """
-      environment variable DATABASE_URL is missing.
-      For example: ecto://USER:PASS@HOST/DATABASE
-      """
+  database_url = build_database_url.()
 
   maybe_ipv6 = if System.get_env("ECTO_IPV6") in ~w(true 1), do: [:inet6], else: []
 
@@ -41,12 +105,12 @@ if config_env() == :prod do
   # want to use a different value for prod and you most likely don't want
   # to check this value into version control, so we use an environment
   # variable instead.
+  # Supports SECRET_KEY_BASE or SECRET_KEY_BASE_FILE for Docker secrets.
   secret_key_base =
-    System.get_env("SECRET_KEY_BASE") ||
-      raise """
-      environment variable SECRET_KEY_BASE is missing.
-      You can generate one by calling: mix phx.gen.secret
-      """
+    get_env_or_file!.("SECRET_KEY_BASE", """
+    environment variable SECRET_KEY_BASE (or SECRET_KEY_BASE_FILE) is missing.
+    You can generate one by calling: mix phx.gen.secret
+    """)
 
   host = System.get_env("PHX_HOST") || raise "Please define the PHX_HOST environment variable."
   port = String.to_integer(System.get_env("PORT") || "4000")
@@ -54,32 +118,47 @@ if config_env() == :prod do
   config :mv, :dns_cluster_query, System.get_env("DNS_CLUSTER_QUERY")
 
   # Rauthy OIDC configuration
+  # Supports OIDC_CLIENT_SECRET or OIDC_CLIENT_SECRET_FILE for Docker secrets.
+  # OIDC_CLIENT_SECRET is required only if OIDC is being used (indicated by explicit OIDC env vars).
+  oidc_base_url = System.get_env("OIDC_BASE_URL")
+  oidc_client_id = System.get_env("OIDC_CLIENT_ID")
+  oidc_in_use = not is_nil(oidc_base_url) or not is_nil(oidc_client_id)
+
+  client_secret =
+    if oidc_in_use do
+      get_env_or_file!.("OIDC_CLIENT_SECRET", """
+      environment variable OIDC_CLIENT_SECRET (or OIDC_CLIENT_SECRET_FILE) is missing.
+      This is required when OIDC authentication is configured (OIDC_BASE_URL or OIDC_CLIENT_ID is set).
+      """)
+    else
+      get_env_or_file.("OIDC_CLIENT_SECRET", nil)
+    end
+
   config :mv, :rauthy,
-    client_id: System.get_env("OIDC_CLIENT_ID") || "mv",
-    base_url: System.get_env("OIDC_BASE_URL") || "http://localhost:8080/auth/v1",
-    client_secret: System.get_env("OIDC_CLIENT_SECRET"),
+    client_id: oidc_client_id || "mv",
+    base_url: oidc_base_url || "http://localhost:8080/auth/v1",
+    client_secret: client_secret,
     redirect_uri:
       System.get_env("OIDC_REDIRECT_URI") || "http://#{host}:#{port}/auth/user/rauthy/callback"
 
   # Token signing secret from environment variable
   # This overrides the placeholder value set in prod.exs
+  # Supports TOKEN_SIGNING_SECRET or TOKEN_SIGNING_SECRET_FILE for Docker secrets.
   token_signing_secret =
-    System.get_env("TOKEN_SIGNING_SECRET") ||
-      raise """
-      environment variable TOKEN_SIGNING_SECRET is missing.
-      You can generate one by calling: mix phx.gen.secret
-      """
+    get_env_or_file!.("TOKEN_SIGNING_SECRET", """
+    environment variable TOKEN_SIGNING_SECRET (or TOKEN_SIGNING_SECRET_FILE) is missing.
+    You can generate one by calling: mix phx.gen.secret
+    """)
 
   config :mv, :token_signing_secret, token_signing_secret
 
   config :mv, MvWeb.Endpoint,
     url: [host: host, port: 443, scheme: "https"],
     http: [
-      # Enable IPv6 and bind on all interfaces.
-      # Set it to  {0, 0, 0, 0, 0, 0, 0, 1} for local network only access.
+      # Bind on all IPv4 interfaces.
+      # Use {0, 0, 0, 0, 0, 0, 0, 0} for IPv6, or {127, 0, 0, 1} for localhost only.
       # See the documentation on https://hexdocs.pm/bandit/Bandit.html#t:options/0
-      # for details about using IPv6 vs IPv4 and loopback vs public addresses.
-      ip: {0, 0, 0, 0, 0, 0, 0, 0},
+      ip: {0, 0, 0, 0},
       port: port
     ],
     secret_key_base: secret_key_base,

docker-compose.prod.yml

@@ -2,21 +2,32 @@ services:
   app:
     image: git.local-it.org/local-it/mitgliederverwaltung:latest
     container_name: mv-prod-app
-    # Use host network for local testing to access localhost:8080 (Rauthy)
-    # In real production, remove this and use external OIDC provider
-    network_mode: host
+    ports:
+      - "4001:4001"
     environment:
-      DATABASE_URL: "ecto://postgres:postgres@localhost:5001/mv_prod"
-      SECRET_KEY_BASE: "${SECRET_KEY_BASE}"
-      TOKEN_SIGNING_SECRET: "${TOKEN_SIGNING_SECRET}"
-      PHX_HOST: "${PHX_HOST}"
+      # Database configuration using separate variables
+      # Use Docker service name for internal networking
+      DATABASE_HOST: "db-prod"
+      DATABASE_PORT: "5432"
+      DATABASE_USER: "postgres"
+      DATABASE_NAME: "mv_prod"
+      DATABASE_PASSWORD_FILE: "/run/secrets/db_password"
+      # Phoenix secrets via Docker secrets
+      SECRET_KEY_BASE_FILE: "/run/secrets/secret_key_base"
+      TOKEN_SIGNING_SECRET_FILE: "/run/secrets/token_signing_secret"
+      PHX_HOST: "${PHX_HOST:-localhost}"
       PORT: "4001"
       PHX_SERVER: "true"
-      # Rauthy OIDC config - uses localhost because of host network mode
+      # Rauthy OIDC config - use host.docker.internal to reach host services
       OIDC_CLIENT_ID: "mv"
-      OIDC_BASE_URL: "http://localhost:8080/auth/v1"
-      OIDC_CLIENT_SECRET: "${OIDC_CLIENT_SECRET:-}"
+      OIDC_BASE_URL: "http://host.docker.internal:8080/auth/v1"
+      OIDC_CLIENT_SECRET_FILE: "/run/secrets/oidc_client_secret"
       OIDC_REDIRECT_URI: "http://localhost:4001/auth/user/rauthy/callback"
+    secrets:
+      - db_password
+      - secret_key_base
+      - token_signing_secret
+      - oidc_client_secret
     depends_on:
       - db-prod
     restart: unless-stopped
@@ -26,13 +37,25 @@ services:
     container_name: mv-prod-db
     environment:
       POSTGRES_USER: postgres
-      POSTGRES_PASSWORD: postgres
+      POSTGRES_PASSWORD_FILE: /run/secrets/db_password
       POSTGRES_DB: mv_prod
+    secrets:
+      - db_password
     volumes:
       - postgres_data_prod:/var/lib/postgresql/data
     ports:
       - "5001:5432"
     restart: unless-stopped
 
+secrets:
+  db_password:
+    file: ./secrets/db_password.txt
+  secret_key_base:
+    file: ./secrets/secret_key_base.txt
+  token_signing_secret:
+    file: ./secrets/token_signing_secret.txt
+  oidc_client_secret:
+    file: ./secrets/oidc_client_secret.txt
+
 volumes:
   postgres_data_prod: