Update README.md

.dockerignore

@@ -0,0 +1,46 @@
+# This file excludes paths from the Docker build context.
+#
+# By default, Docker's build context includes all files (and folders) in the
+# current directory. Even if a file isn't copied into the container it is still sent to
+# the Docker daemon.
+#
+# There are multiple reasons to exclude files from the build context:
+#
+# 1. Prevent nested folders from being copied into the container (ex: exclude
+#    /assets/node_modules when copying /assets)
+# 2. Reduce the size of the build context and improve build time (ex. /build, /deps, /doc)
+# 3. Avoid sending files containing sensitive information
+#
+# More information on using .dockerignore is available here:
+# https://docs.docker.com/engine/reference/builder/#dockerignore-file
+
+.dockerignore
+
+# Ignore git, but keep git HEAD and refs to access current commit hash if needed:
+#
+# $ cat .git/HEAD | awk '{print ".git/"$2}' | xargs cat
+# d0b8727759e1e0e7aa3d41707d12376e373d5ecc
+.git
+!.git/HEAD
+!.git/refs
+
+# Common development/test artifacts
+/cover/
+/doc/
+/test/
+/tmp/
+.elixir_ls
+
+# Mix artifacts
+/_build/
+/deps/
+*.ez
+
+# Generated on crash by the VM
+erl_crash.dump
+
+# Static artifacts - These should be fetched and built inside the Docker image
+# https://phoenix.hexdocs.pm/Mix.Tasks.Phx.Gen.Release.html#module-docker
+/assets/node_modules/
+/priv/static/assets/
+/priv/static/cache_manifest.json

Dockerfile

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+# Find eligible builder and runner images on Docker Hub. We use Ubuntu/Debian
+# instead of Alpine to avoid DNS resolution issues in production.
+#
+# https://hub.docker.com/r/hexpm/elixir/tags?name=ubuntu
+# https://hub.docker.com/_/ubuntu/tags
+#
+# This file is based on these images:
+#
+#   - https://hub.docker.com/r/hexpm/elixir/tags - for the build image
+#   - https://hub.docker.com/_/debian/tags?name=trixie-20260610-slim - for the release image
+#   - https://pkgs.org/ - resource for finding needed packages
+#   - Ex: docker.io/hexpm/elixir:1.18.4-erlang-28.5.0.2-debian-trixie-20260610-slim
+#
+ARG ELIXIR_VERSION=1.18.4
+ARG OTP_VERSION=28.5.0.2
+ARG DEBIAN_VERSION=trixie-20260610-slim
+
+ARG BUILDER_IMAGE="docker.io/hexpm/elixir:${ELIXIR_VERSION}-erlang-${OTP_VERSION}-debian-${DEBIAN_VERSION}"
+ARG RUNNER_IMAGE="docker.io/debian:${DEBIAN_VERSION}"
+
+FROM ${BUILDER_IMAGE} AS builder
+
+# install build dependencies
+RUN apt-get update \
+  && apt-get install -y --no-install-recommends build-essential git \
+  && rm -rf /var/lib/apt/lists/*
+
+# prepare build dir
+WORKDIR /app
+
+# install hex + rebar
+RUN mix local.hex --force \
+  && mix local.rebar --force
+
+# set build ENV
+ENV MIX_ENV="prod"
+
+# install mix dependencies
+COPY mix.exs mix.lock ./
+RUN mix deps.get --only $MIX_ENV
+RUN mkdir config
+
+# copy compile-time config files before we compile dependencies
+# to ensure any relevant config change will trigger the dependencies
+# to be re-compiled.
+COPY config/config.exs config/${MIX_ENV}.exs config/
+RUN mix deps.compile
+
+RUN mix assets.setup
+
+COPY priv priv
+
+COPY lib lib
+
+# Compile the release
+RUN mix compile
+
+COPY assets assets
+
+# compile assets
+RUN mix assets.deploy
+
+# Changes to config/runtime.exs don't require recompiling the code
+COPY config/runtime.exs config/
+
+COPY rel rel
+RUN mix release
+
+# start a new build stage so that the final image will only contain
+# the compiled release and other runtime necessities
+FROM ${RUNNER_IMAGE} AS final
+
+RUN apt-get update \
+  && apt-get install -y --no-install-recommends libstdc++6 openssl libncurses6 locales ca-certificates \
+  && rm -rf /var/lib/apt/lists/*
+
+# Set the locale
+RUN sed -i '/en_US.UTF-8/s/^# //g' /etc/locale.gen \
+  && locale-gen
+
+ENV LANG=en_US.UTF-8
+ENV LANGUAGE=en_US:en
+ENV LC_ALL=en_US.UTF-8
+
+WORKDIR "/app"
+RUN chown nobody /app
+
+# set runner ENV
+ENV MIX_ENV="prod"
+
+# Only copy the final release from the build stage
+COPY --from=builder --chown=nobody:root /app/_build/${MIX_ENV}/rel/rsh26pool ./
+
+USER nobody
+
+# If using an environment that doesn't automatically reap zombie processes, it is
+# advised to add an init process such as tini via `apt-get install`
+# above and adding an entrypoint. See https://github.com/krallin/tini for details
+# ENTRYPOINT ["/tini", "--"]
+
+CMD ["/app/bin/server"]

README.md

@@ -103,3 +103,46 @@ mix precommit
 ```
 
 > テストは `DATABASE_URL` の接続先サーバー上に、専用の `..._test` データベースを自動的に作成して実行します。
+
+## Docker でのデプロイ
+
+Docker を使って本番用リリースをビルド・起動できます。データベース接続 URL は、コンテナの **起動時** に環境変数 `DATABASE_URL` から読み込まれます（イメージには埋め込まれません）。
+
+### 1. イメージのビルド
+
+```bash
+docker build -t rsh26pool:latest .
+```
+
+### 2. マイグレーションの実行
+
+```bash
+docker run --rm \
+  -e DATABASE_URL="ecto://ユーザー名:パスワード@DBホスト:5432/rsh26pool_prod" \
+  -e SECRET_KEY_BASE="$(mix phx.gen.secret)" \
+  rsh26pool:latest /app/bin/migrate
+```
+
+### 3. サーバーの起動
+
+```bash
+docker run -p 4000:4000 \
+  -e DATABASE_URL="ecto://ユーザー名:パスワード@DBホスト:5432/rsh26pool_prod" \
+  -e SECRET_KEY_BASE="生成したシークレット" \
+  -e PHX_HOST="example.com" \
+  rsh26pool:latest
+```
+
+起動後、ブラウザで [`http://localhost:4000`](http://localhost:4000) にアクセスしてください。
+
+### 環境変数
+
+| 変数 | 必須 | 説明 |
+| --- | --- | --- |
+| `DATABASE_URL` | 必須 | データベース接続 URL（例：`ecto://ユーザー名:パスワード@DBホスト:5432/rsh26pool_prod`）。 |
+| `SECRET_KEY_BASE` | 必須 | Cookie の署名・暗号化に使用。`mix phx.gen.secret` で生成できます。 |
+| `PHX_HOST` | 推奨 | 公開ホスト名。未設定時は `example.com`。 |
+| `PORT` | 任意 | 待ち受けポート。既定は `4000`。 |
+| `POOL_SIZE` | 任意 | DB コネクションプールのサイズ。既定は `10`。 |
+
+> 本番設定（`config/prod.exs`）では `force_ssl`（HSTS）が有効です。`localhost` 以外のホストでは `https` にリダイレクトされるため、TLS を終端して `x-forwarded-proto` ヘッダーを付与するリバースプロキシの背後で運用してください。

lib/rsh26pool/release.ex

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+defmodule Rsh26pool.Release do
+  @moduledoc """
+  Used for executing DB release tasks when run in production without Mix
+  installed.
+  """
+  @app :rsh26pool
+
+  def migrate do
+    load_app()
+
+    for repo <- repos() do
+      {:ok, _, _} = Ecto.Migrator.with_repo(repo, &Ecto.Migrator.run(&1, :up, all: true))
+    end
+  end
+
+  def rollback(repo, version) do
+    load_app()
+    {:ok, _, _} = Ecto.Migrator.with_repo(repo, &Ecto.Migrator.run(&1, :down, to: version))
+  end
+
+  defp repos do
+    Application.fetch_env!(@app, :ecto_repos)
+  end
+
+  defp load_app do
+    # Many platforms require SSL when connecting to the database
+    Application.ensure_all_started(:ssl)
+    Application.ensure_loaded(@app)
+  end
+end

rel/overlays/bin/migrate

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+#!/bin/sh
+set -eu
+
+cd -P -- "$(dirname -- "$0")"
+exec ./rsh26pool eval Rsh26pool.Release.migrate

rel/overlays/bin/migrate.bat

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+call "%~dp0\rsh26pool" eval Rsh26pool.Release.migrate

rel/overlays/bin/server

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+#!/bin/sh
+set -eu
+
+cd -P -- "$(dirname -- "$0")"
+PHX_SERVER=true exec ./rsh26pool start

rel/overlays/bin/server.bat

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+set PHX_SERVER=true
+call "%~dp0\rsh26pool" start