PEX runtime environment variables

PEX_ALWAYS_CACHE

Boolean.

Deprecated: This env var is no longer used; all internally cached distributions in a PEX are always installed into the local Pex dependency cache.

PEX_COVERAGE

Boolean.

Enable coverage reporting for this PEX file. This requires that the “coverage” module is available in the PEX environment.

Default: false.

PEX_COVERAGE_FILENAME

Filename.

Write the coverage data to the specified filename. If PEX_COVERAGE_FILENAME is not specified but PEX_COVERAGE is, coverage information will be printed to stdout and not saved.

PEX_DISABLE_VARIABLES

Boolean.

Disable reading of all PEX_* variables (except this one) from all sources. Both PEX_* environment variables and PEX_* variables sources from pexrc files will be ignored.

This can be used to lock down the function of a PEX.

PEX_EMIT_WARNINGS

Boolean.

Emit UserWarnings to stderr. When false, warnings will only be logged at PEX_VERBOSE >= 1. When unset the build-time value of –emit-warnings will be used.

Default: unset.

PEX_EXTRA_SYS_PATH

String.

A ‘:’ or ‘;’ separated string containing paths to add to the runtime sys.path.

Should be used sparingly, e.g., if you know that code inside this PEX needs to interact with code outside it.

For example, on a Unix system: “/path/to/lib1:/path/to/lib2”

This is distinct from PEX_INHERIT_PATH, which controls how the interpreter’s existing sys.path (which you may not have control over) is scrubbed.

See also PEX_PATH for how to merge packages from other pexes into the current environment.

PEX_FORCE_LOCAL

Boolean.

Deprecated: This env var is no longer used since user code is now always unzipped before execution.

PEX_IGNORE_ERRORS

Boolean.

Ignore any errors resolving dependencies when invoking the PEX file. This can be useful if you know that a particular failing dependency is not necessary to run the application.

Default: false.

PEX_IGNORE_RCFILES

Boolean.

Explicitly disable the reading/parsing of pexrc files (~/.pexrc).

Default: false.

PEX_INHERIT_PATH

String (false|prefer|fallback)

Allow inheriting packages from site-packages, user site-packages and the PYTHONPATH. By default, PEX scrubs any non stdlib packages from sys.path prior to invoking the application. Using ‘prefer’ causes PEX to shift any non-stdlib packages before the pex environment on sys.path and using ‘fallback’ shifts them after instead.

Using this option is generally not advised, but can help in situations when certain dependencies do not conform to standard packaging practices and thus cannot be bundled into PEX files.

See also PEX_EXTRA_SYS_PATH for how to add to the sys.path.

Default: false.

PEX_INTERPRETER

Boolean.

Drop into a REPL instead of invoking the predefined entry point of this PEX. This can be useful for inspecting the PEX environment interactively. It can also be used to treat the PEX file as an interpreter in order to execute other scripts in the context of the PEX file, e.g. “PEX_INTERPRETER=1 ./app.pex my_script.py”. Equivalent to setting PEX_MODULE to empty.

Default: false.

PEX_INTERPRETER_HISTORY

Boolean.

IF PEX_INTERPRETER is true, use a command history file for REPL user convenience. The location of the history file is determined by PEX_INTERPRETER_HISTORY_FILE.

Default: false.

PEX_INTERPRETER_HISTORY_FILE

File.

IF PEX_INTERPRETER_HISTORY is true, use this history file. The default is the standard Python interpreter history location.

Default: ~/.python_history.

PEX_MAX_INSTALL_JOBS

Integer.

The maximum number of parallel jobs to use when installing third party dependencies contained in a PEX during its first boot. Values are interpreted as follows:

• >=2 Dependencies should be installed in parallel using exactly this maximum number of jobs.

• 1 Dependencies should be installed in serial.

• 0 The maximum number of parallel jobs should be auto-selected taking the number of cores into account.

• -1 The maximum number of parallel jobs should be auto-selected taking both the characteristics of the third party dependencies contained in the PEX and the number of cores into account. The third party dependency heuristics are intended to yield good install performance, but are opaque and may change across PEX releases if better heuristics are discovered.

• <=-2 These are illegal values; an error is raised.

Default: 1

PEX_MODULE

String.

Override the entry point into the PEX file. Can either be a module, e.g. ‘SimpleHTTPServer’, or a specific entry point in module:symbol form, e.g. “myapp.bin:main”.

PEX_PATH

A set of one or more PEX files.

Merge the packages from other PEX files into the current environment. This allows you to do things such as create a PEX file containing the “coverage” module or create PEX files containing plugin entry points to be consumed by a main application. Paths should be specified in the same manner as $PATH. For example, on a Unix system PEX_PATH=/path/to/pex1.pex:/path/to/pex2.pex and so forth.

See also PEX_EXTRA_SYS_PATH for how to add arbitrary entries to the sys.path.

PEX_PROFILE

Boolean.

Enable application profiling. If specified and PEX_PROFILE_FILENAME is not specified, PEX will print profiling information to stdout.

PEX_PROFILE_FILENAME

Filename.

Profile the application and dump a profile into the specified filename in the standard “profile” module format.

PEX_PROFILE_SORT

String.

Toggle the profile sorting algorithm used to print out profile columns.

Default: ‘cumulative’.

PEX_PYTHON

String.

Override the Python interpreter used to invoke this PEX. Can be either an absolute path to an interpreter or a base name e.g. “python3.3”. If a base name is provided, the $PATH will be searched for an appropriate match.

PEX_PYTHON_PATH

String.

A ‘:’ or ‘;’ separated string containing paths of blessed Python interpreters for overriding the Python interpreter used to invoke this PEX. Can be absolute paths to interpreters or standard $PATH style directory entries that are searched for child files that are python binaries.

For example, on a Unix system: “/path/to/python27:/path/to/python36-distribution/bin”

PEX_ROOT

Directory.

The directory location for PEX to cache any dependencies and code. PEX must write not-zip- safe eggs and all wheels to disk in order to activate them.

Default: ~/.pex

PEX_SCRIPT

String.

The script name within the PEX environment to execute. This must either be an entry point as defined in a distribution’s console_scripts, or a script as defined in a distribution’s scripts section. While Python supports any script including shell scripts, PEX only supports invocation of Python scripts in this fashion.

PEX_TEARDOWN_VERBOSE

Boolean.

Enable verbosity for when the interpreter shuts down. This is mostly only useful for debugging PEX itself.

Default: false.

PEX_TOOLS

Boolean.

Run the PEX tools.

Default: false.

PEX_UNZIP

Boolean.

Deprecated: This env var is no longer used since unzipping PEX zip files before execution is now the default.

PEX_VENV

Boolean.

Force this PEX to create a venv under $PEX_ROOT and re-execute from there. If the pex file will be run multiple times under a stable $PEX_ROOT the venv creation will only be performed once and subsequent runs will enjoy lower startup latency.

Default: false.

PEX_VENV_BIN_PATH

String (false|prepend|append).

When running in PEX_VENV mode, optionally add the scripts and console scripts of distributions in the PEX file to the $PATH.

Default: false.

PEX_VERBOSE

Integer.

Set the verbosity level of PEX debug logging. The higher the number, the more logging, with 0 being disabled. This environment variable can be extremely useful in debugging PEX environment issues.

Default: 0