PID/Hostname File Locking for Cluster Environments.

[willow-ahrens]

The PID file locking ecosystem in Python may not be robust to the networked filesystems common to HPC clusters, which may have multiple hosts on multiple operating systems.

Quoting @amilsted:

Julia core uses https://github.com/vtjnash/Pidfile.jl to do hostname/PID-based locking to JuliaLang/julia#42405 and JuliaLang/julia#42405, because this type of locking is JuliaLang/julia#31953.

A successful fix for this issue would identify and integrate a python pidfile implementation which offers the same (tested) guarantees as https://github.com/vtjnash/Pidfile.jl. Further discussion in #45, where FileLock may be used as an interim solution.