Fix and improve Dockerfile.

Author: bovender

CHANGELOG.md

@@ -5,6 +5,16 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Version 3.0.1 (2025-06-29)][v3.0.1]
+
+### Changed
+
+- Updated dependencies.
+
+### Fixed
+
+- Docker image now works again for real (finally fixes #10?).
+
 ## [Version 3.0.0 (2025-04-21)][v3.0.0]
 
 ### Fixed
@@ -93,6 +103,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fix: Docker image.
 - Fix: Options error message.
 
+[v3.0.1]: https://github.com/bovender/imapcli/releases/tag/v3.0.1
 [v3.0.0]: https://github.com/bovender/imapcli/releases/tag/v3.0.0
 [v2.1.0]: https://github.com/bovender/imapcli/releases/tag/v2.1.0
 [v2.0.1]: https://github.com/bovender/imapcli/releases/tag/v2.0.1

Dockerfile

@@ -1,18 +1,22 @@
-FROM ruby:3.4-alpine
-LABEL maintainer="bovender@bovender.de"
-LABEL description="Command-line tool to query IMAP servers, collect stats etc."
-
-WORKDIR /
-ADD . /imapcli
-RUN apk add --no-cache git build-base && \
+FROM ruby:3.5-rc AS builder
+WORKDIR /imapcli
+COPY Gemfile Gemfile.lock imapcli.gemspec .
+COPY lib/imapcli/version.rb lib/imapcli/version.rb
+RUN apt-get update -qq && \
+  apt-get install -y build-essential libc6 && \
   gem update --system && \
-  cd imapcli && \
   bundle config set --local without development test && \
   bundle config set --local deployment true && \
-  bundle install && \
-  apk del build-base && \
-  rm -rf /var/cache/apk/*
+  bundle install
 
+FROM ruby:3.5-rc-slim
+LABEL maintainer="bovender@bovender.de"
+LABEL description="Command-line tool to query IMAP servers, collect stats etc."
 WORKDIR /imapcli
+RUN apt-get update -qq && \
+  apt-get install -y git && \
+  apt-get clean && rm -rf /var/lib/apt/lists/*
+COPY --from=builder /usr/local/bundle /usr/local/bundle
+COPY --from=builder /imapcli/vendor /imapcli/vendor
+COPY . .
 ENTRYPOINT ["bundle", "exec", "exe/imapcli"]
-