Environment variables

These are the environment variables used to customize conan.

CONAN_CMAKE_GENERATOR

Conan CMake helper class is just a convenience to help to translate conan settings and options into cmake parameters, but you can easily do it yourself, or adapt it.

For some compiler configurations, as gcc it will use by default the Unix Makefiles cmake generator. Note that this is not a package settings, building it with makefiles or other build system, as Ninja, should lead to the same binary if using appropriately the same underlying compiler settings. So it doesn’t make sense to provide a setting or option for this.

So it can be set with the environment variable CONAN_CMAKE_GENERATOR. Just set its value to your desired cmake generator (as Ninja).

CONAN_USER_HOME

Allows defining a custom conan cache directory. Can be useful for concurrent builds under different users in CI, to retrieve and store per-project specific dependencies (useful for deployment, for example).

Read more about it in Virtual environments: concurrency, Continuous Integration, isolation

CONAN_LOGGING_LEVEL

By default this environment varible is = 50, which means only logging critical events. If you want to show more detailed logging information, set this variable to lower values, as 10 to show debug information

CONAN_COMPRESSION_LEVEL

Conan uses tgz compression for archives before uploading them to remotes. The default compression level is 9, which is good compression and fast enough for most cases, but users with huge packages might want to change it and set CONAN_COMPRESSION_LEVEL environment variable to a lower number, which is able to get slightly bigger archives but much better compression speed.

CONAN_SYSREQUIRES_SUDO

This environment variable controls whether sudo is used for installing apt, yum, etc. system packages via SystemPackageTool helper, typically used in system_requirements(). Set it to “False” or “0” to don’t use sudo.

CONAN_COLOR_DISPLAY

Useful to remove colored output, set it to CONAN_COLOR_DISPLAY=0 to remove console output colors

CONAN_COLOR_DARK

Set it to CONAN_COLOR_DARK=1 to use dark colors in the terminal output, instead of light ones. Useful for terminal or consoles with light colors as white, so text is rendered in Blue, Black, Magenta, instead of Yellow, Cyan, White.

CONAN_USER, CONAN_CHANNEL

Environment variables commonly used in test_package conanfiles, to allow package creation for different users and channel without modifying the code. They are also the environment variables that will be checked when using self.user or self.channel in conanfile.py package recipes in user space, where a user/channel has not been assigned yet (it is assigned when exported in the local cache)

Read more about it in user, channel

CONAN_ENV_XXXX_YYYY

You can override the default settings (located in your ~/.conan/profiles/default directory) with environment variables.

The XXXX is the setting name upper-case, and the YYYY (optional) is the sub-setting name.

Examples:

  • Override the default compiler:
CONAN_ENV_COMPILER = "Visual Studio"
  • Override the default compiler version:
CONAN_ENV_COMPILER_VERSION = "14"
  • Override the architecture:
CONAN_ENV_ARCH = "x86"

CONAN_BASH_PATH

Used only in windows to help the tools.run_in_windows_bash() function to locate our Cygwin/MSYS2 bash. Set it with the bash executable path if it’s not in the PATH or you want to use a different one.

CONAN_TRACE_FILE

If you want extra logging information about your conan command executions, you can enable it by setting the CONAN_TRACE_FILE environment variable. Set it with an absolute path to a file, e.j: export CONAN_TRACE_FILE=/tmp/conan_trace.log

When the conan command is executed, some traces will be appended to the specified file. Each line contains a JSON object. The _action field contains the action type, like COMMAND for command executions, EXCEPTION for errors and REST_API_CALL for HTTP calls to a remote.

The logger will append the traces until the CONAN_TRACE_FILE variable is unset or pointed to a different file.

Read more here: How to log and debug a conan execution

CONAN_LOG_RUN_TO_FILE

Defaulted to “0”. If it’s set to “1” will log every self.run("{Some command}") command output in a file called conan_run.log. That file will be located in the current execution directory, so if we call self.run in the conanfile.py’s build method, the file will be located in the build folder.

In case we execute self.run in our source method, the conan_run.log will be created in the source directory, but then conan will copy it to the build folder following the regular execution flow. So the conan_run.log will contain all the logs from your conanfile.py command executions.

The file can be included in the conan package (for debugging purposes) using the package method.

def package(self):
    self.copy(pattern="conan_run.log", dst="", keep_path=False)

CONAN_LOG_RUN_TO_OUTPUT

Defaulted to “1”. If it’s set to “0” conan won’t print the command output to the stdout. Can be used with CONAN_LOG_RUN_TO_FILE set to “1” to log only to file and not printing the output.

CONAN_PRINT_RUN_COMMANDS

Defaulted to “0”. If it is set to “1” every self.run("{Some command}") call will log the executed command {Some command} to the output. E.j. In the conanfile.py file:

self.run("cd %s && %s ./configure" % (self.ZIP_FOLDER_NAME, env_line))

Will print to the output (stout and/or file):

...
----Running------
> cd zlib-1.2.9 && env LIBS="" LDFLAGS=" -m64   $LDFLAGS" CFLAGS="-mstackrealign -fPIC $CFLAGS -m64  -s -DNDEBUG  " CPPFLAGS="$CPPFLAGS -m64  -s -DNDEBUG  " C_INCLUDE_PATH=$C_INCLUDE_PATH: CPLUS_INCLUDE_PATH=$CPLUS_INCLUDE_PATH: ./configure
-----------------
...

CONAN_CPU_COUNT

Set the number of cores that the tools.cpu_count() will return, by default the number of cores available in your machine. Conan recipes can use the cpu_count() tool to build the library using more than one core.