Finding available Ansible tags in playbooks and roles

Jan 4, 2017 · 3 minute read · Comments
tripleo linux bash ansible

Today I went down a yak shaving path trying to figure out how to get all the available tags in a fairly complicated plethora of Ansible playbooks and roles. One of these such situations involves TripleO Quickstart, which is made up of several different playbooks and repositories of different roles.

Of course there is the nice feature of ansible-playbook that you could run ansible-playbook --list-tags which outputs something like the following:

playbook: playbooks/quickstart.yml

  play #1 (localhost): Add the virthost to the inventory	TAGS: [provision]
      TASK TAGS: [provision]

  play #2 (virthost): Tear down non-root user on virt host	TAGS: [teardown-provision,teardown-all]
      TASK TAGS: [teardown-all, teardown-provision]

  play #3 (localhost): Add virthost to inventory	TAGS: [provision]
      TASK TAGS: [provision]

  play #4 (virthost): Create non root user on the virthost	TAGS: [provision]
      TASK TAGS: [provision]

  play #5 (virthost): Create target user on virt host	TAGS: [provision]
      TASK TAGS: [provision]

The problem I’ve found is that running from the top level playbook (if there is even one) requires that all the other playbooks and roles are included in it to know for certain that you’ve gotten all the available tags.

So instead of relying on that, I built out a bash script that goes through the playbooks in a loop, teasing out all the available tags, creating a list of them, then sorting them and spitting out the unique values.

In all its infamous glory…

for i in $(ls playbooks/*.yml)
do
    ansible-playbook --list-tags $i 2>&1
done |
grep "TASK TAGS" |
cut -d":" -f2 |
awk '{sub(/\[/, "")sub(/\]/, "")}1' |
sed -e 's/,//g' |
xargs -n 1 |
sort -u

I told you it was a yak shaving exercise. And now that our yak sits in its birthday suit, we can analyze all the bits of what made this monstrosity a reality.

First, we setup a for loop that runs through all our playbooks (it is assumed that any roles you care about are called at least once from any of the playbooks in your repository). We then request Ansible to return us the available tags that is called from the playbook.

for i in $(ls playbooks/*.yml)
do
    ansible-playbook --list-tags $i 2>&1
done |

Then we grep out the list of tags.

grep "TASK TAGS" |

Grab just the tags themselves.

cut -d":" -f2 |

Strip off the opening and closing braces.

awk '{sub(/\[/, "")sub(/\]/, "")}1' |

Remove the comma separating lists of tags.

sed -e 's/,//g' |

Place each of the various tags on their own line.

xargs -n 1 |

And sort the tags, returning only the unique values.

sort -u

Conclusion

The funny thing, is I had an even more complicated solution as I found shyaml[1] which is pretty damn cool, but really is kind of a pain to work with if you’re trying to filter on sequences (which is pretty much all my Ansible playbooks consist of).

Additionally, it hates the block statement, and shyaml basically bails at that point. The script I had before also only found a subset of the tags.

I may still be missing some things as even Ansible was bombing on some particular syntax in the playbooks, although I’m relatively assured that I’ve gotten all the tags.

Leif Madsen

Finding available Ansible tags in playbooks and roles

Conclusion