#2301 pex 2.1.154 New discussion created by github-actions[bot] * * * 2.1.154 This release brings three new features: 1. When creating PEXes without specifying an explicit

--python-shebang

, an appropriate shebang is chosen correctly in more cases than previously and a warning is emitted when the shebang chosen cannot be guaranteed to be correct. The common case this helps select the appropriate shebang for is PEXes built using

--platform

or

--complete-platform

. 2. PEXes can now be created with

--no-pre-install-wheels

to cut down PEX build times with a tradeoff of roughly 10% greater boot overhead upon the 1st execution of the PEX file. For PEXes with very large dependency sets (machine learning provides common cases), the build time savings can be dramatic. 3. PEXes can now be told to install dependencies at runtime on 1st execution using parallel processes using

--max-install-jobs

at PEX build time or by setting the

PEX_MAX_INSTALL_JOBS

environment variable at runtime. The last two features come with complicated tradeoffs and are turned off by default as a result. If you think they might help some of your use cases, there is more detail in the command line help for

--no-pre-install-wheels

and

--max-install-jobs

as well as in the

pex --help-variables

output for

PEX_MAX_INSTALL_JOBS

. You can also find a detailed performance analysis in #2292 for the extreme cases of very small and very large PEXes. In the end though, experimenting is probably your best bet. • Use appropriate shebang for multi-platform PEXes. (#2296) • Add support for --no-pre-install-wheels and --max-install-jobs. (#2298) * * * This discussion was created from the release pex 2.1.154. pantsbuild/pex