Hi Experts, Actually i am very new to Pants.. I am facing issues running my pex file in another system . We are using the command (PEX_TOOLS=1 ./pants my_webapp:my_webapp) to package our python project to a pex file. We have developed our project using python 3.7 and i want to bundle and run it as a pex package in a system which has python 2.7 in it without any dependencies. But when i try to run this on the system i m getting the below error:

[vagrant@localhost ~]$ ./my_webapp.pex 
/usr/bin/env: python3.9: No such file or directory
[vagrant@localhost ~]$ python --version
Python 2.7.5

So how do i ship venv with the project as a single PEX file, so that this can be executed in any system we want to without any python version requirement? Some expert opinion/advise is much appreciated!! TIA

A few questions first: + What version of Pants are you using? + What is the intention of using

PEX_TOOLS=1

in

PEX_TOOLS=1 ./pants my_webapp:my_webapp

? + Can you provide your BUILD file target? You should be able to configure your BUILD file target to both package your PEX file for multiple target Python versions and use a neutral shebang. For modern Pants that would be by using the

interpreter_constraints

(or

platforms

) and

shebang

fields of the

pex_binary

target. So, part 1 - build the PEX file for multiple Pythons: 1.) You need to run Pants on a machine with all the Python versions you're targeting if the PEX will contain any non-universal wheels. 2.) Add

interpreter_constraints=[">=2.7,<4"]

to your

pex_binary

target: https://www.pantsbuild.org/docs/reference-pex_binary#codeinterpreter_constraintscode Part 2 - ensure the resulting PEX file shebang is

#!/usr/bin/env python

instead of `#!/usr/bin/python3.9`: 1.) Add

shebang="/usr/bin/env python"

to your

pex_binary

target. You can check the result of this step by running Pants to generate the PEX file and executing

head -1 <path to my PEX file>

. You should get

#!/usr/bin/env python

hi @enough-analyst-54434 We are able to get a single pex file but when we are trying to run that in a system that has python 2.7 , we are getting the below error:

$./my_app_play.pex
Traceback (most recent call last):
  File "/home/sancbane/my_app_play.pex/.bootstrap/pex/pex.py", line 488, in execute
  File "/home/sancbane/my_app_play.pex/.bootstrap/pex/pex.py", line 144, in activate
  File "/home/sancbane/my_app_play.pex/.bootstrap/pex/pex.py", line 131, in _activate
  File "/home/sancbane/my_app_play.pex/.bootstrap/pex/environment.py", line 427, in activate
  File "/home/sancbane/my_app_play.pex/.bootstrap/pex/environment.py", line 775, in _activate
  File "/home/sancbane/my_app_play.pex/.bootstrap/pex/environment.py", line 601, in resolve
  File "/home/sancbane/my_app_play.pex/.bootstrap/pex/environment.py", line 686, in resolve_dists
pex.environment.ResolveError: Failed to resolve requirements from PEX environment @ /home/sancbane/my_app_play.pex.
Needed manylinux_2_17_x86_64-cp-27-cp27mu compatible dependencies for:
 1: psutil
    Required by:
      ansible-runner 1.4.7
    But this pex had no u'psutil' distributions.
 2: PyYAML
    Required by:
      ansible-runner 1.4.7
    But this pex had no u'PyYAML' distributions

Please find our pants.toml file below:

[GLOBAL]
pants_version = "2.4.1"

backend_packages = [
  'pants.backend.python',
  'pants.backend.python.lint.black',
  'pants.backend.python.lint.isort',
  'pants.backend.python.lint.flake8',
  'pants.backend.python.typecheck.mypy',
]

[source]
root_patterns = [
  '/',
]

[python-setup]
# The default interpreter compatibility for code in this repo. Individual targets can override
#  this with the `interpreter_constraints` field. See
#  <https://www.pantsbuild.org/docs/python-interpreter-compatibility>.
interpreter_constraints = [">=2.7"]

# Use a constraints file. See <https://www.pantsbuild.org/docs/python-third-party-dependencies>.
requirement_constraints = "my_app_playbooks/python/constraints.txt"

# We search for interpreters on both on the $PATH and in the `$(pyenv root)/versions` folder.
#  If you're using macOS, you may want to leave off the <PATH> entry to avoid using the
#  problematic system Pythons. See
#  <https://www.pantsbuild.org/docs/python-interpreter-compatibility#changing-the-interpreter-search-path>.
interpreter_search_paths = ["<PATH>", "<PYENV>"]

Could you please advise us on the same

@white-address-70112 your interpreter constraints look good; however, Pants (really Pex) will only resolve using the interpreters it can find on your system when building the PEX file. I'm guessing you simply don't have a Python 2.7 interpreter on the machine where you are running Pants to create the PEX file. Is that right?

1. I have written code in Python3 and build the pex file on my mac system which has python 2.7 and 3.7 versions. 2. The PEX file is working fine on the mac system. 3. when i copy that pex file into a system which has linux and run python 2.7 on it , i get the mentioned error.

Aha. Yeah, so for a multi-platform PEX you need to use

platforms

instead of interpreter constraints: https://www.pantsbuild.org/docs/reference-pex_binary#codeplatformscode Also, you'll need to have pre-built wheels available for all distributions. Neither Pants nor Pex has cross-building magic. This is confusing enough that I should provide an example. I'll prepare an example-python branch for you to look at.

I m currently using the below parameters

platforms=[
    "manylinux_2_17_x86_64-cp-27-cp27mu",
    "linux_x86_64-cp-27-cp27mu",
    "macosx_10.12_x86_64-cp-36-cp36m",
  ],

but when i try to package it i m getting the below error:

sanchayan@sanchayan-mac pex_build % ./pants package my_app_playbooks:my_app_play
19:27:42.68 [INFO] Completed: Resolving 2 requirements: ansible-runner, requests
19:27:42.68 [ERROR] Exception caught: (pants.engine.internals.scheduler.ExecutionError)
  File "/Users/sanchayan/.cache/pants/setup/bootstrap-Darwin-x86_64/2.4.1_py37/lib/python3.7/site-packages/pants/bin/local_pants_runner.py", line 229, in _run_inner
    return self._perform_run(goals)
  File "/Users/sanchayan/.cache/pants/setup/bootstrap-Darwin-x86_64/2.4.1_py37/lib/python3.7/site-packages/pants/bin/local_pants_runner.py", line 168, in _perform_run
    return self._perform_run_body(goals, poll=False)
  File "/Users/sanchayan/.cache/pants/setup/bootstrap-Darwin-x86_64/2.4.1_py37/lib/python3.7/site-packages/pants/bin/local_pants_runner.py", line 190, in _perform_run_body
    poll_delay=(0.1 if poll else None),
  File "/Users/sanchayan/.cache/pants/setup/bootstrap-Darwin-x86_64/2.4.1_py37/lib/python3.7/site-packages/pants/init/engine_initializer.py", line 136, in run_goal_rules
    goal_product, params, poll=poll, poll_delay=poll_delay
  File "/Users/sanchayan/.cache/pants/setup/bootstrap-Darwin-x86_64/2.4.1_py37/lib/python3.7/site-packages/pants/engine/internals/scheduler.py", line 530, in run_goal_rule
    self._raise_on_error([t for _, t in throws])
  File "/Users/sanchayan/.cache/pants/setup/bootstrap-Darwin-x86_64/2.4.1_py37/lib/python3.7/site-packages/pants/engine/internals/scheduler.py", line 500, in _raise_on_error
    wrapped_exceptions=tuple(t.exc for t in throws),

Exception message: 1 Exception encountered:

  ProcessExecutionFailure: Process 'Resolving 2 requirements: ansible-runner, requests' failed with exit code 1.
stdout:

stderr:
ERROR: Could not find a version that satisfies the requirement ansible-runner
ERROR: No matching distribution found for ansible-runner
ERROR: Could not find a version that satisfies the requirement ansible-runner
ERROR: No matching distribution found for ansible-runner
pid 84331 -> /System/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python /Users/sanchayan/.cache/pants/named_caches/pex_root/pip.pex/cf4106b4c7898b462f7c172dde686a9747103f1a --disable-pip-version-check --no-python-version-warning --exists-action a --use-feature 2020-resolver --isolated -q --cache-dir /Users/sanchayan/.cache/pants/named_caches/pex_root --log /private/var/folders/py/mw_r2yw93rv65p8zp60whqqw0000gn/T/process-executiontYLj2S/.tmp/tmpjXFBnp/pip.log download --dest /private/var/folders/py/mw_r2yw93rv65p8zp60whqqw0000gn/T/process-executiontYLj2S/.tmp/tmpZ4uxsO/linux_x86_64-cp-27-cp27mu --platform manylinux2014_x86_64 --platform linux_x86_64 --implementation cp --python-version 27 --abi cp27mu --only-binary :all: --constraint my_app_playbooks/python/constraints.txt ansible-runner requests --index-url <https://pypi.org/simple/> --retries 5 --timeout 15 exited with 1 and STDERR:
None



(Use --print-stacktrace to see more error details.)

Yeah, that's just saying there is no Linux python 2.7 pre-built wheel available. That's the part where Pants / Pex is not magic. They cannot cross build a Linux wheel on your Mac. You'll need to pre-build any needed Linux wheels that aren't available on PyPI and host them at a location you can add to

[python-repos] repos

Yes @enough-analyst-54434 that makes sense.. But we are getting another issue 😞

Can you provide a listing of that PEX file? `unzip -l ./dist//my_playbooks/play.pex' should do it. Or better, can you provide the PEX file itself?

my_app_pex_unzip_lst.txt

Hrm, that does have a

__main__.py

. The uncompressed size of the PEX zip is ~700MB which is not interesting. It has 120,950 files (entries) though and that is potentially interesting since storing more than ~2^16 files requires zip64 extensions. .... and - lo and behold: https://bugs.python.org/issue32959

@enough-analyst-54434 FYI: if we put ansible in constraints it not packaging so we have imported the ansible in entrypoint pex_build % cat casper_sre_playbooks/python/constraints.txt requests sshtunnel psutil ansible-runner

@full-intern-53951 one problem at a time please. I just want to make sure this 1st problem is understood. Does it make sense?

@enough-analyst-54434 Got it, so do we need to try changing interpreter_constraints to 3.9 ?

interpreter_constraints=[">=3.9.0","<=3.9.9"],

I proved this bug is present in python 3.8 but not python 3.9 with this myself:

mkdir test && for i in `seq 1 120950`; do touch test/example_$i.py; done
zip -q numerous_but_small.zip test/
$ PYTHONPATH=numerous_but_small.zip python3.8 -c 'import test.example_1; print(test.example_1.__file__)'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ModuleNotFoundError: No module named 'test.example_1'
$ PYTHONPATH=numerous_but_small.zip python3.9 -c 'import test.example_1; print(test.example_1.__file__)'
/home/jsirois/Downloads/test/example_1.py

Sounds good, our goal is build the executable and we can install python 3.9 in target system, I am currently trying to build with interpreter_constraints=[">=3.9.0","<=3.9.9"],

To be clear here: Pex itself can handle zip64; it's only the bootstrap process that happens before Pex runtime code is executed, that cannot on python <= 3.8. That code is CPython c code that implements zip support. And that CPython c code doesn't handle zip64. The python zipfile module does though! That's implemented in python.

@enough-analyst-54434 I used the same as you mentioned, but It seem pants using python3.8 for bootstrapping ./pants package my_app_playbooks:my_app_play --print-stacktrace -ldebug Bootstrapping Pants using /Library/Frameworks/Python.framework/Versions/3.8/bin/python3.8 Downloading the virtualenv zipapp

That's fine. A confusing thing is Pants itself needs a Python to run Pants with. Pants can accept Python 3.7, 3.8 or 3.9. It will build your code though using the interpreter you asked for.

pex_binary(
  shebang="/usr/bin/env python3.9",
  name='my_app_play',
  entry_point='my_app_play.py',
  zip_safe=False,
  execution_mode="unzip",
  interpreter_constraints=[">=3.9,<4"],

)

also, I see it not packaging ansible, please check the below 7.96s Resolving 4 requirements: ansible-runner, psutil, requests, sshtunnel

You shouldn't need that shebang setting, although it causes no harm - in other words, if you remove that field from your pex_binary - you should still get a PEX file with a python 3.9 shebang.

after I built it 3.9, execution is failing with below error as ansible module did not packaged import ansible ModuleNotFoundError: No module named 'ansible'

So, does any of your code actually

import ansible

? If not, Pants can't know ansible should be included.

in entry point

import ansible

Yes we are importing ansible inside "my_app_play.py"

And you have a python_library() target along side that pex_binary target in the same BUILD file?

from python_library:

python_library(
  dependencies = [
    'my_app_playbooks/configs',
    'my_app_playbooks/configs/my_rba_config.py',
    'my_app_playbooks/telemetry',
    'my_app_playbooks/clients',
    'my_app_playbooks/playbooks',
    './ansible_runner',
    ':all',
    './configs:json_resources',
    'my_app_playbooks/python:requirements.txt',
  ],
)

So one super suspicious thing is that your requirements.txt has no version constrainst for ansible and the latest ansible is 4.1.0 released 5 days agio, but your listing of the python3.8 zip has ansible 3.4.0.

we are adding ansible version in the requiremment.txt file and repackaging it

What version of Pants is this by the way? You may have answered in some other thread but I've forgotten if so.

2.4.1

What does the following command say for your pex_binary target?:

./pants dependencies --transitive --type=source-and-3rdparty your/pex_binary:target

Depens.txt

In that listing I do not see my_app_play.py which is your pex_binary entrypoint. Am I just missing it?

can we exclude python file like below, will that work

resources(
  name='all',
  sources=['**', '!*.py'],
)

That should work.

This time it picked up, but we see below error WARNING: Discarding https://files.pythonhosted.org/packages/42/c6/e97fbab98d4d80f423cfdb3f82ed2d6461d9e608cd93422242b072d47b1a/ansible-4.1.0.tar.gz#sha256=f561cca7fbc4daa14d98e18cd0cb74bd8b173f1501b8fa11543f6ef002de3167 (from https://pypi.org/simple/ansible/) (requires-python:>=2.7,!=3.0.,!=3.1.,!=3.2.,!=3.3.,!=3.4.*). Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output. ERROR: Could not find a version that satisfies the requirement ansible ERROR: No matching distribution found for ansible

Just to back up a bit. There was a key lesson there. Pants dependency inference only works if files have unique target ownership. Keep that strongly in mind. There is a tension since ** seems more convenient. You'll get burned by that though as here.

@enough-analyst-54434 the PEX is working fine from my system, but see issue executing it from target system it is not working % ./my_app_play.pex -t IOS-33165 validating auth token.... Remediation starting for cschema-service-01301.node.ad1.1 heartbeat : casper_heartbeat.yml casper_heartbeat.yml ERROR! Unexpected Exception, this is probably a bug: No module named ‘psutil’ to see the full traceback, use -vvv

Sure, so tell me more about your system vs the other. How are they different?

we see the psutil is packaged in the binary

What prefix does psutil have in the PEX?

Is it a known issue? https://github.com/ansible/ansible-runner/issues/54

both are mac

Ok. And both macs do have a python3.9 interpreter on the PATH?

currently I am using below parameters in pex_binary

zip_safe=False,
execution_mode="unzip",

Maybe, but 1st, can you confirm both macs have python3.9 on the PATH?

yes both are MAC with python3.9

K. Try removing the zip_safe field and setting execution_mode="venv".

okay

Hrm. One debugging approach is to try to build this same PEX on the other machine and then compare PEX files for differences.

sure, we try tomorrow, actually we work in IST time zone (India) and its already Morning for us, it is a great help, we were able to fix some of the issues, Tomorrow we will try building it on other system and keep you posted

You're welcome. Hopefully you'll find differences in the PEX files tomorrow and that will make the remedy obvious.

hi @enough-analyst-54434 could you please help us with the procedure to build executable for linux from mac

@enough-analyst-54434 Good Morning, It working fine after we installing the pip install Ansible but when I extract the pex I can see 2 ansible whl directories in .deps drwxr-xr-x 4 gtripura staff 128 Jan 1 1980 ansible-4.1.0-py3-none-any.whl drwxr-xr-x 4 gtripura staff 128 Jan 1 1980 ansible-3.1.0-py3-none-any.whl

Hey folks. I'm out of the office here for a few weeks. You'll need to cast a wider net for help. Before doing that though it may make sense to internally decide on one person to be the primary communicator and have that person come up with a good summary of the current problems such that whoever takes over helping you out can quickly understand the relevant details.