Crystal container images and DEB/RPM packages

Multi-architecture (amd64 and arm64) container image and DEB/RPM package builder for the Crystal compiler. The images are built daily using GitHub actions.

The container images are published at https://hub.docker.com/r/84codes/crystal and the packages at https://packagecloud.com/84codes/crystal

Usage

Use these images when you want to build your Crystal app, (pro tip: always use a multi stage approach).

FROM 84codes/crystal:1.4.1-ubuntu-22.04 AS builder
WORKDIR /usr/src/app
# Copying and install dependencies
COPY shard.yml shard.lock .
RUN shards install --production
# Copying the rest of the code
COPY src src
# Build binaries
RUN shards build --release --no-debug

# start from a clean ubuntu image
FROM ubuntu:22.04
# install required dependencies
RUN apt-get update && \
    apt-get install -y libssl3 libevent-2.1-7 && \
    apt-get clean && \
    rm -rf /var/cache/apt/* /var/lib/apt/lists/* /var/cache/debconf/* /var/log/*
# copy the compiled binary from the build stage
COPY --from=builder /usr/src/app/bin/* /usr/local/bin/
ENTRYPOINT ["/usr/local/bin/myapp"]

Smallest images are achieved with static compiled binaries added to a scratch image:

# Compile in a build stage
FROM 84codes/crystal:1.4.1-alpine-latest as builder
WORKDIR /tmp
# Copying and install dependencies
COPY shard.yml shard.lock ./
RUN shards install --production
# Copy the rest of the code
COPY src/ src/
# Build a static binary
RUN shards build --release --production --static --no-debug

# The scratch image is completely empty
FROM scratch
# Don't run as root
USER 2:2
# Copy only the binary from the build stage
COPY --from=builder /tmp/bin/* /
# Install a CA store, only needed if the application verifies TLS peers (eg. talk to a https server)
COPY --from=builder /etc/ssl/cert.pem /etc/ssl/
# Set default entrypoint
ENTRYPOINT ["/myapp"]

Supported OSes and versions

Alpine latest
Ubuntu 20.04
Ubuntu 22.04
Debian Buster
Debian Bullseye
Fedora 35
Fedora 36

Supported Crystal version(s)

More versions are easily added, but currently images are build for these Crystal versions:

1.4.1

DEB/RPM packages

DEB and RPM packages are built both for amd64 and arm64, and published at https://packagecloud.io/84codes/crystal.

For best performance use dynamically built packages, they link to the distribution's libraries (there for only a few current versions are supported). For other distributions and versions, use the statically compiled binaries.

Install

Dynamically linked binaries for recent and current Ubuntu/Debian versions

curl -fsSL https://packagecloud.io/84codes/crystal/gpgkey | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/84codes_crystal.gpg
. /etc/os-release
echo "deb https://packagecloud.io/84codes/crystal/$ID $VERSION_CODENAME main" | sudo tee /etc/apt/sources.list.d/84codes_crystal.list
apt-get update
apt-get install crystal

Dynamically linked binaries for recent and current Fedora versions

sudo tee /etc/yum.repos.d/84codes_crystal.repo << 'EOF'
[84codes_crystal]
name=84codes_crystal
baseurl=https://packagecloud.io/84codes/crystal/fedora/$releasever/$basearch
gpgkey=https://packagecloud.io/84codes/crystal/gpgkey
repo_gpgcheck=1
gpgcheck=0
EOF
sudo dnf install crystal

Any Deb based distributions

curl -fsSL https://packagecloud.io/84codes/crystal/gpgkey | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/84codes_crystal.gpg
echo "deb https://packagecloud.io/84codes/crystal/any any main" | sudo tee /etc/apt/sources.list.d/84codes_crystal.list
apt-get update
apt-get install crystal

Any RPM based distributions

sudo tee /etc/yum.repos.d/84codes_crystal.repo << 'EOF'
[84codes_crystal]
name=84codes_crystal
baseurl=https://packagecloud.io/84codes/crystal/rpm_any/rpm_any/$basearch
gpgkey=https://packagecloud.io/84codes/crystal/gpgkey
repo_gpgcheck=1
gpgcheck=0
EOF
sudo dnf install crystal

The static packages are built using the binaries from the alpine container and packaged up using fpm.

The alpine image is built (multi-arch using buildx+qemu), then in the pkgs dockerfile the files from the alpine container are packaged up and copied to a scratch image, from which the packages are exported and then uploaded to packagecloud.

For details please see:

stakach/crystal-container-images