Running and deploying packages

Executables and applications including shared libraries can also be distributed, deployed and run with Conan. This might have some advantages compared to deploying with other systems:

  • A unified development and distribution tool, for all systems and platforms

  • Manage any number of different deployment configurations in the same way you manage them for development

  • Use a Conan server remote to store all your applications and runtimes for all Operating Systems, platforms and targets

There are different approaches:

Using virtual environments

We can create a package that contains an executable, for example from the default package template created by conan new:

$ conan new Hello/0.1

The source code used contains an executable called greet, but it is not packaged by default. Let’s modify the recipe package() method to also package the executable:

def package(self):
    self.copy("*greet*", src="hello/bin", dst="bin", keep_path=False)

Now we create the package as usual, but if we try to run the executable it won’t be found:

$ conan create . user/testing
...
Hello/0.1@user/testing package(): Copied 1 '.h' files: hello.h
Hello/0.1@user/testing package(): Copied 1 '.exe' files: greet.exe
Hello/0.1@user/testing package(): Copied 1 '.lib' files: hello.lib

$ greet
> ... not found...

By default, Conan does not modify by default the environment, it will just create the package in the local cache, and that is not in the system PATH, so the greet executable is not found.

The virtualrunenv generator generates files that add the package’s default binary locations to the necessary paths:

  • It adds the dependencies lib subfolder to the DYLD_LIBRARY_PATH environment variable (for OSX shared libraries)

  • It adds the dependencies lib subfolder to the LD_LIBRARY_PATH environment variable (for Linux shared libraries)

  • It adds the dependencies bin subfolder to the PATH environment variable (for executables)

So if we install the package, specifying such virtualrunenv like:

$ conan install Hello/0.1@user/testing -g virtualrunenv

This will generate a few files that can be called to activate and deactivate the required environment variables

$ activate_run.sh # $ source activate_run.sh in Unix/Linux
$ greet
> Hello World!
$ deactivate_run.sh # $ source deactivate_run.sh in Unix/Linux

Imports

It is possible to define a custom conanfile (either .txt or .py), with an imports section, that can retrieve from local cache the desired files. This approach requires a user conanfile. For more details see example below runtime packages

Deployable packages

With the deploy() method, a package can specify which files and artifacts to copy to user space or to other locations in the system. Let’s modify the example recipe adding the deploy() method:

def deploy(self):
    self.copy("*", dst="bin", src="bin")

And run conan create

$ conan create . user/testing

With that method in our package recipe, it will copy the executable when installed directly:

$ conan install Hello/0.1@user/testing
...
> Hello/0.1@user/testing deploy(): Copied 1 '.exe' files: greet.exe
$ bin\greet.exe
> Hello World!

The deploy will create a deploy_manifest.txt file with the files that have been deployed.

Sometimes it is useful to adjust the package ID of the deployable package in order to deploy it regardless of the compiler it was compiled with:

def package_id(self):
    del self.info.settings.compiler

See also

Read more about the deploy() method.

Running from packages

If a dependency has an executable that we want to run in the conanfile, it can be done directly in code using the run_environment=True argument. It internally uses a RunEnvironment helper. For example, if we want to execute the greet app while building the Consumer package:

from conans import ConanFile, tools, RunEnvironment

class ConsumerConan(ConanFile):
    name = "Consumer"
    version = "0.1"
    settings = "os", "compiler", "build_type", "arch"
    requires = "Hello/0.1@user/testing"

    def build(self):
        self.run("greet", run_environment=True)

Now run conan install and conan build for this consumer recipe:

$ conan install . && conan build .
...
Project: Running build()
Hello World!

Instead of using the environment, it is also possible to explicitly access the path of the dependencies:

def build(self):
    path = os.path.join(self.deps_cpp_info["Hello"].rootpath, "bin")
    self.run("%s/greet" % path)

Note that this might not be enough if shared libraries exist. Using the run_environment=True helper above is a more complete solution.

Finally, there is another approach: the package containing the executable can add its bin folder directly to the PATH. In this case the Hello package conanfile would contain:

def package_info(self):
    self.cpp_info.libs = ["hello"]
    self.env_info.PATH = os.path.join(self.package_folder, "bin")

We may also define DYLD_LIBRARY_PATH and LD_LIBRARY_PATH if they are required for the executable.

The consumer package is simple, as the PATH environment variable contains the greet executable:

def build(self):
    self.run("greet")

Runtime packages and re-packaging

It is possible to create packages that contain only runtime binaries, getting rid of all build-time dependencies. If we want to create a package from the above “Hello” one, but only containing the executable (remember that the above package also contains a library, and the headers), we could do:

from conans import ConanFile

class HellorunConan(ConanFile):
    name = "HelloRun"
    version = "0.1"
    build_requires = "Hello/0.1@user/testing"
    keep_imports = True

    def imports(self):
        self.copy("greet*", src="bin", dst="bin")

    def package(self):
        self.copy("*")

This recipe has the following characteristics:

  • It includes the Hello/0.1@user/testing package as build_requires. That means that it will be used to build this HelloRun package, but once the HelloRun package is built, it will not be necessary to retrieve it.

  • It is using imports() to copy from the dependencies, in this case, the executable

  • It is using the keep_imports attribute to define that imported artifacts during the build() step (which is not define, then using the default empty one), are kept and not removed after build

  • The package() method packages the imported artifacts that will be created in the build folder.

To create and upload this package to a remote:

$ conan create . user/testing
$ conan upload HelloRun* --all -r=my-remote

Installing and running this package can be done using any of the methods presented above. For example:

$ conan install HelloRun/0.1@user/testing -g virtualrunenv
# You can specify the remote with -r=my-remote
# It will not install Hello/0.1@...
$ activate_run.sh # $ source activate_run.sh in Unix/Linux
$ greet
> Hello World!
$ deactivate_run.sh # $ source deactivate_run.sh in Unix/Linux