Checking if a list is empty...

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1

Hi,

My inventory script returns the correct JSON for a host including an empty list for ‘listen_ips’, i.e:

{ “listen_ips”: }

I want to include a task only if the listen_ips list contains at least one element. This doesn’t work:

  • { include: tasks/repo_server.yml, when: listen_ips > 0 }

Any ideas?

Cheers
GS

2

maybe just check if its got the first element:

- { include: tasks/repo_server.yml, when: listen_ips.0 is defined }

Kahlil (Kal) Hodgson GPG: C9A02289
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3

Thanks for the mega-fast response :slight_smile: That works!

  • GS
4

​
​
when: listen_ips|length > 0​

5

Serge's response is fine but I believe you can also just do:

- { include: tasks/repo_server.yml, when: listen_ips }

Python lists have a truthiness of False when empty.

6

Thanks Serge.

  • GS
7

This is the first thing that I tried, but it gave me an error about being unable to evaluate the conditional.

  • GS
8

“when: listen_ips|length > 0”

this.