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Showing posts from September, 2012

out: an output utility

Intro Whilst writing the tests for the Job Logging feature in Upstart, I discovered that I needed some very specific job behaviour that was not easy to produce using any simple existing utility I could find. The Problem What I wanted was a utility that would produce specified amounts of data to either standard output, standard error or direct to the terminal without using shell redirection. The reason for eschewing the shell being that Upstart is clever and intelligently determines whether a shell should be involved. From a user perspective, that's fantastic, but for testing purposes, I needed to force Upstart down particular code paths where it would not for example automatically pass the job through a shell. In fact the constraint was even more restrictive; what I really wanted to do was this: Produce output (including null bytes) to stdout, stderr or the terminal without using any shell meta characters. Unless I used some extremely esoteric shell, that effective...

Call for Testing: Upstart stateful re-exec

If you'd like to help out testing the new "stateful re-exec" feature of Upstart which we hope to land for Ubuntu Quantal, see the details here: https://lists.ubuntu.com/archives/upstart-devel/2012-September/001948.html In brief (more posts will follow), "stateful re-exec" allows Upstart to be restarted (or upgraded!) without rebooting your system. A basic restart or re-exec isn't difficult, but what stateful re-exec does is maintain Upstarts internal state over the re-exec such that it continues to track jobs and log job output. This is an early cut of the code so don't install it on any critical systems . Additionally, there are some caveats... https://wiki.ubuntu.com/FoundationsTeam/Specs/QuantalUpstartStatefulReexec#Phase_1_Limitations ... but we plan for that list to dwindle quickly over the coming days and weeks.