How can I start and stop a background task on travis?

Question

I need to start and restart a custom web server on travis. Starting in background is fine using a sub-shell (.travis.yml):

- if [ "$TEST_ADAPTER" = "HTTP" ]; then (vendor/bin/httpd.php start &); fi

To stop/kill the process again I'm trying to get its PID and then kill it:

- if [ "$TEST_ADAPTER" = "HTTP" ]; then (vendor/bin/httpd.php start &) && SERVER_PID=$!; fi
- ...
- if [ "$TEST_ADAPTER" = "HTTP" ]; then kill -9 $SERVER_PID && ...; fi

However, SERVER_PID is empty.

What is the right way to obtain the PID of a background process on travis in order to stop it (complication: without using an additional shell script)?

score 9 · Answer 1 · answered Apr 23 '15 at 14:30

9

Answering question here as @xmonk's answer is correct in terms of functionality but requires an external shell script which- in turn- would need to use a temp file to write the pid value to.

I've just found out that travis-ci does actually allow multi-line statements which simplified the whole thing. Put this in .travis.yml:

- |
  if [ "$TEST_ADAPTER" = "HTTP" ]; then
    vendor/bin/httpd.php&
    SERVER_PID=$!
  fi

answered Apr 23 '15 at 14:30

andig

13,378
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61
98

After this, you can use `- kill $SERVER_PID` in a separate step. The variable `$SERVER_PID` will be preserved across steps. – Mr-IDE Oct 02 '18 at 01:38

score 3 · Accepted Answer · answered Apr 22 '15 at 15:24

3

The following should work:

if [ "$TEST_ADAPTER" = "HTTP" ]; then
    vendor/bin/httpd.php&
    SERVER_PID=$!
fi

The () surrounding the command, creates a sub-shell. The $! comes empty in your examples, because the program is running in the sub-shell, but your $! is running on the parent shell.

answered Apr 22 '15 at 15:24

xmonk

535
6
13

As far as I know I can't write multi-lien statements in travis.yml https://groups.google.com/forum/#!topic/travis-ci/uaAP9zEdiCg – andig Apr 22 '15 at 16:14
Right, but you can put the above in a shell script, and run that script from your .travis.yml file. – xmonk Apr 22 '15 at 16:35
You can write multi-line statements in Travis CI YAML using the `|` multiline operator, see: https://www.jeffgeerling.com/blog/2017/bash-logic-structures-and-conditionals-if-case-loops-etc-travis-ci – geerlingguy Apr 11 '18 at 20:26

How can I start and stop a background task on travis?

2 Answers2

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