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.

If you need more control over the build and execution of the container, you can define more parameters inside a configfile yaml.

For example, you can add arguments in the build step or environment variables when you launch the container.

To use it, you just need to add it in the host profile.

[settings]
...
[runner]
type=docker
configfile=</my/runner/folder>/configfile
cache=copy
remove=false

How to use

Let’s create a Dockerfile inside your project folder, a cmake_lib myparamlib like the “Creating a Conan package using a Docker runner” example and two profiles.

$ cd </my/runner/folder>
$ mkdir myparamlib
$ cd myparamlib
$ conan new cmake_lib -d name=myparamlib -d version=0.1
$ cd </my/runner/folder>
$ tree
.
├── CMakeLists.txt
├── conanfile.py
├── include
│   └── myparamlib.h
├── src
│   └── myparamlib.cpp
└── test_package
    ├── CMakeLists.txt
    ├── conanfile.py
    └── src
        └── example.cpp

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

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

$ cd </my/runner/folder>/myparamlib
$ tree
.
...
├── Dockerfile
...
├── configfile
...

docker_param_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>/myparamlib/configfile
cache=copy
remove=false

docker_param_example_build profile

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

Now it’s time to create our new library.

$ conan create . --version 0.1 -pr:h docker_param_example_host -pr:b docker_param_example_build
...
****************************************************
* Building the Docker image: my-conan-runner-image *
****************************************************
Dockerfile path: '</my/runner/folder>/myparamlib/Dockerfile'
Docker build context: '</my/runner/folder>/myparamlib'
Step 1/5 : ARG BASE_IMAGE
Step 2/5 : FROM $BASE_IMAGE
...
Successfully built caa8071cdff7
Successfully tagged my-conan-runner-image:latest
...
**************************************************************************************************************************************************************************
* Running in container: "conan create /root/conanrunner/myparamlib --version 0.1 -pr:h docker_param_example_host -pr:b docker_param_example_build -f json > create.json" *
**************************************************************************************************************************************************************************
...
[ 50%] Building CXX object CMakeFiles/example.dir/src/example.cpp.o
[100%] Linking CXX executable example
[100%] Built target example
======== Testing the package: Executing test ========
myparamlib/0.1 (test package): Running test()
myparamlib/0.1 (test package): RUN: ./example
myparamlib/0.1: Hello World Release!
myparamlib/0.1: __x86_64__ defined
myparamlib/0.1: _GLIBCXX_USE_CXX11_ABI 1
myparamlib/0.1: __cplusplus201703
myparamlib/0.1: __GNUC__11
myparamlib/0.1: __GNUC_MINOR__4
myparamlib/0.1 test_package
**********************************************************************************************
* Restore host cache from: </my/runner/folder>/myparamlib/.conanrunner/docker_cache_save.tgz *
**********************************************************************************************
Saving myparamlib/0.1: mypar36e44205a36b9
Saving myparamlib/0.1:8631cf963dbbb4d7a378a64a6fd1dc57558bc2fe: b/mypare0dc449d4125d/p
Saving myparamlib/0.1:8631cf963dbbb4d7a378a64a6fd1dc57558bc2fe metadata: b/mypare0dc449d4125d/d/metadata

If we now check the status of our conan cache, we will see the new myparamlib pacakge.

$ conan list "*:*"
Found 1 pkg/version recipes matching * in local cache
Local Cache
myparamlib
    myparamlib/0.1
    revisions
        11cb359a0526fe9ce3cfefb59c5d1953 (2024-07-08 12:47:21 UTC)
        packages
            8631cf963dbbb4d7a378a64a6fd1dc57558bc2fe
            info
                settings
                arch: x86_64
                build_type: Release
                compiler: gcc
                compiler.cppstd: gnu17
                compiler.libcxx: libstdc++11
                compiler.version: 11
                os: Linux
                options
                fPIC: True
                shared: False