About

CMake script that downloads and builds conan packages from github using provided options.

See as example https://github.com/blockspacer/chromium_base_conan/blob/master/get_conan_dependencies.cmake

Where to store SCRIPT_PATH file?

Best practices is to create get_conan_dependencies.cmake file near conanfile.py (or near conanfile.txt).

get_conan_dependencies.cmake file must contain cmake code that creates all dependencies i.e. it does not auto-detect dependencies of dependencies.

That will allow to continue working even if ConanCenter server goes down.

Why build from sources

Some people do not like to install binaries.

If you think that it is beneficial to build software from sources - you may prefer conan_github_downloader

Gentoo answer why build from sources

How it works

conan_github_downloader.cmake includes script provided by SCRIPT_PATH.

Use cmake -P to run conan_github_downloader.cmake:

cmake \
  -DSCRIPT_PATH="$PWD/my_script.cmake" \
  -DEXTRA_CONAN_OPTS="--profile;default" \
  -P tools/conan_github_downloader.cmake

You can provide multiple conan options:

cmake \
  -DSCRIPT_PATH="$PWD/get_conan_dependencies.cmake"\
  -DEXTRA_CONAN_OPTS="--profile;clang\
;-s;build_type=Debug\
;-s;cling_conan:build_type=Release\
;-s;llvm_tools:build_type=Release\
;--build;missing" \
  -P ~/conan_github_downloader/conan_github_downloader.cmake

About SCRIPT_PATH file contents

First, create directory where git repos must be cloned:

if(EXISTS "${CURRENT_SCRIPT_DIR}/.tmp")
  cmake_remove_directory("${CURRENT_SCRIPT_DIR}/.tmp")
endif()

cmake_make_dir("${CURRENT_SCRIPT_DIR}/.tmp")

Now you can run commands that can clone git repo, remove old conan package and create new package.

Example with best practices:

set(ENABLE_CPPCHECK TRUE CACHE BOOL "ENABLE_CPPCHECK")
if(ENABLE_CPPCHECK
  AND NOT EXISTS "${CURRENT_SCRIPT_DIR}/.tmp/conan-cppcheck_installer")
  git_clone("${CURRENT_SCRIPT_DIR}/.tmp/conan-cppcheck_installer"
      "https://github.com/bincrafters/conan-cppcheck_installer.git"
      "-b;testing/1.90")
endif()
#
set(CLEAN_CPPCHECK FALSE CACHE BOOL "CLEAN_CPPCHECK")
if(ENABLE_CPPCHECK AND CLEAN_CPPCHECK)
  conan_remove_target(conan-cppcheck_installer)
endif()
#
conan_build_target_if(
  "conan-cppcheck_installer" # target to clean
  "conan/stable"
  "${CURRENT_SCRIPT_DIR}/.tmp/conan-cppcheck_installer" # target to build
  ENABLE_CPPCHECK
  "")

Example below clones git repo and creates conan package:

if(NOT EXISTS "${CURRENT_SCRIPT_DIR}/.tmp/flex_support_headers")
  git_clone("${CURRENT_SCRIPT_DIR}/.tmp/flex_support_headers"
      "https://github.com/blockspacer/flex_support_headers.git"
      "")
endif()
conan_build_target_if(
  "flex_support_headers" # target to clean
  "conan/stable"
  "${CURRENT_SCRIPT_DIR}/.tmp/flex_support_headers" # target to build
  ALWAYS_BUILD
  "")

Example below clones git repo branch "testing/1.90" and creates conan package if ENABLE_CPPCHECK is TRUE:

set(ENABLE_CPPCHECK TRUE CACHE BOOL "ENABLE_CPPCHECK")
if(ENABLE_CPPCHECK
  AND NOT EXISTS "${CURRENT_SCRIPT_DIR}/.tmp/conan-cppcheck_installer")
  git_clone("${CURRENT_SCRIPT_DIR}/.tmp/conan-cppcheck_installer"
      "https://github.com/bincrafters/conan-cppcheck_installer.git"
      "-b;testing/1.90")
endif()
conan_build_target_if(
  "conan-cppcheck_installer" # target to clean
  "conan/stable"
  "${CURRENT_SCRIPT_DIR}/.tmp/conan-cppcheck_installer" # target to build
  ENABLE_CPPCHECK
  "")

Example below removes conan package if conan search succeeded:

# Runs `conan search` command i.e.
# conan search cppcheck_installer/master@conan/stable \
#   -q "compiler=clang OR compiler=gcc"
conan_search(
  TARGET "conan-cppcheck_installer/master@conan/stable"
  RESULT_VAR_NAME cppcheck_installer_EXISTS
  VERBOSE TRUE
  QUERY -q "compiler=clang OR compiler=gcc"
)
if(cppcheck_installer_EXISTS)
  conan_remove_target(conan-cppcheck_installer)
endif()

You can change conan setting and options, example (note build_type and include_what_you_use):

conan_build_target_if(
  "llvm_9" # target to clean
  "conan/stable"
  "${CURRENT_SCRIPT_DIR}/.tmp/llvm_9" # target to build
  ENABLE_LLVM_9
  ";-s;llvm_9:build_type=Release\
;-o;llvm_9:include_what_you_use=True")

Motivation

Events similar to Bintray Sunset may happen any day, see https://blog.conan.io/2021/03/31/Bintray-sunset-timeline.html

About CLEAN_BUILD option

If can pass -DCLEAN_BUILD=ON than all conan packages from SCRIPT_PATH will be re-created (i.e. will run conan remove before conan create)

cmake \
  -DSCRIPT_PATH="$PWD/integration_tests/integration_test.cmake" \
  -DEXTRA_CONAN_OPTS="--profile;clang\
;-s;build_type=Debug\
;--build;missing" \
  -DCLEAN_BUILD=ON \
  -P conan_github_downloader.cmake

Alternatives

See https://stackoverflow.com/q/62261869

(for contibutors) Integration tests

Run tests before pull requests:

cmake \
  -DSCRIPT_PATH="$PWD/integration_tests/integration_test.cmake" \
  -DEXTRA_CONAN_OPTS="--profile;clang\
;-s;build_type=Debug\
;--build;missing" \
  -P conan_github_downloader.cmake