Using a docker runner configfile to parameterize a Dockerfile

Warning

This feature is experimental and subject to breaking changes. See the Conan stability section for more information.

In this example we are going to see how to use a docker runner configfile to define our Dockerfile base image. Let’s create two profiles and a Dockerfile inside our project folder.

$ cd </my/runner/folder>
$ tree
.
├── Dockerfile
├── configfile
├── docker_example_build
└── docker_example_host

docker_example_host profile

[settings]
arch=x86_64
build_type=Release
compiler=gcc
compiler.cppstd=gnu17
compiler.libcxx=libstdc++11
compiler.version=11
os=Linux
[runner]
type=docker
configfile=</my/runner/folder>/configfile
cache=copy
remove=false

docker_example_build profile

[settings]
arch=x86_64
build_type=Release
compiler=gcc
compiler.cppstd=gnu17
compiler.libcxx=libstdc++11
compiler.version=11
os=Linux

configfile

image: my-conan-runner-image
build:
    dockerfile: </my/runner/folder>
    build_context: </my/runner/folder>
    build_args:
        BASE_IMAGE: ubuntu:22.04
run:
    name: my-conan-runner-container

Dockerfile

ARG BASE_IMAGE
FROM $BASE_IMAGE
RUN apt-get update \
    && DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
        build-essential \
        cmake \
        python3 \
        python3-pip \
        python3-venv \
    && rm -rf /var/lib/apt/lists/*
RUN pip install conan

In this example we are going to start from a totally clean docker, without containers or images. In addition, we are going to have the conan cache also completely empty.

$ conan list "*:*"
Found 0 pkg/version recipes matching * in local cache
$ docker ps --all
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES
$ docker images
REPOSITORY   TAG       IMAGE ID   CREATED   SIZE

Now, we are going to clone and build zlib from conan-center-index and create it using our new runner definition.

$ git clone https://github.com/conan-io/conan-center-index.git --depth 1
$ conan create ./conan-center-index/recipes/zlib/all --version 1.3.1 -pr:h </my/runner/folder>/docker_example_host -pr:b </my/runner/folder>/docker_example_build
...
****************************************************
* Building the Docker image: my-conan-runner-image *
****************************************************
Dockerfile path: '</my/runner/folder>/Dockerfile'
Docker build context: '</my/runner/folder>'
Step 1/5 : ARG BASE_IMAGE
Step 2/5 : FROM $BASE_IMAGE
...
Successfully built 286df085400f
Successfully tagged my-conan-runner-image:latest
...
*********************************
* Creating the docker container *
*********************************
*******************************************
* Container my-conan-runner-image running *
*******************************************
*******************************************
* Running in container: "conan --version" *
*******************************************
************************************************************************************************************************
* Restore host cache from: </my/runner/folder>/conan-center-index/recipes/zlib/all/.conanrunner/docker_cache_save.tgz *
************************************************************************************************************************
Restore: zlib/1.3.1 in p/zlib95420566fc0dd
Restore: zlib/1.3.1:b647c43bfefae3f830561ca202b6cfd935b56205 in p/zlibd59462fc4358e/p
Restore: zlib/1.3.1:b647c43bfefae3f830561ca202b6cfd935b56205 metadata in p/zlibd59462fc4358e/d/metadata
**********************
* Stopping container *
**********************

If we now check the status of our Conan and docker cache, we will see the zlib package compiled for Linux and the new docker image and container.

$ conan list "*:*"
Found 1 pkg/version recipes matching * in local cache
Local Cache
  zlib
    zlib/1.3.1
    revisions
        e20364c96c45455608a72543f3a53133 (2024-04-29 17:18:07 UTC)
        packages
            b647c43bfefae3f830561ca202b6cfd935b56205
            info
                settings
                arch: x86_64
                build_type: Release
                compiler: gcc
                compiler.version: 11
                os: Linux
                options
                fPIC: True
                shared: False
$ docker ps --all
CONTAINER ID   IMAGE                   COMMAND                  CREATED          STATUS                       PORTS     NAMES
1379072ae424   my-conan-runner-image   "/bin/bash -c 'while…"   17 seconds ago   Exited (137) 2 seconds ago             my-conan-runner-image
$ docker images
REPOSITORY        TAG       IMAGE ID       CREATED          SIZE
my-conan-runner   latest    383b905f352e   22 minutes ago   531MB
ubuntu            22.04     437ec753bef3   12 days ago      77.9MB

If we run the conan create command again we will see how Conan reuses the previous container because we have set remove=False.

$ conan create ./conan-center-index/recipes/zlib/all --version 1.3.1 -pr:h </my/runner/folder>/docker_example_host -pr:b </my/runner/folder>/docker_example_build
...
*********************************
* Starting the docker container *
*********************************
...