* moved tests from filters to actual jinja2 tests
also removed some unused declarations and imports
* split tests into their own docs
removed isnan as existing jinja2's 'number' already covers same
added missing docs for several tests
* updated as per feedback
At its most basic, this is nothing more than an array or hash lookup,
but when used in conjunction with map, it is very useful. For example,
while constructing an "ssh-keyscan …" command to update known_hosts on
all hosts in a group, one can get a list of IP addresses with:
groups['x']|map('extract', hostvars, 'ec2_ip_address')|list
This returns hostvars[a].ec2_ip_address, hostvars[b].ec2_ip_address, and
so on. You can even specify an array of keys for a recursive lookup, and
mix string and integer keys depending on what you're looking up:
['localhost']|map('extract', hostvars, ['vars','group_names',0])|first
== hostvars['localhost']['vars']['group_names'][0]
== 'ungrouped'
Includes documentation and tests.
This is based on some code from (closed) PR #7872, but reworked based on
suggestions by @abadger and the other core team members.
Closes#7872 by @darkk (hash_merge/hash_replace filters)
Closes#11153 by @telbizov (merged_dicts lookup plugin)