Conditional if the variable exists and does not exist-CodePudding

I have a YAML data like this :

peers:
  eth1:
    hostname: host-01
    state: Idle
  eth2:
    hostname: host-02
    state: Established
  eth3:
    hostname: host-03
    state: Established
ping_to:
  host-02: success
  host-03: success

with jinja2,Ii want to define something like this:

{% for key, value in peers.iteritems() %}
{% for key2, value2 in ping.iteritems() %}
{% if value.hostname is exist in key2 %}
ping is success
{% elif value.hostname is not exist key2 %}
ping not found
{% endif %}
{% endfor %}
{% endfor %}

So basically if the hostname value is in one of the ping keys, then it is a success. If not, then fail. how to say it if the hostname exists or does not exist?

CodePudding user response：

You actually do not need that nested loop, you could simply assert that the hostname value is a key in the ping_to dictionnary:

{% for interface_name, interface_value in peers.items() %}
  {%- if ping_to[interface_value.hostname] is defined -%}
    ping is success
  {%- else -%}
    ping is not found
  {%- endif %}
{% endfor %}

Another, simpler way, would be to use the default filter, to have an alternative output when the key is indeed not defined.

{% for interface_name, interface_value in peers.items() -%}
  ping is {{ ping_to[interface_value.hostname] | default('not found') }}
{% endfor %}

Both those snippets would give:

ping is success
ping is success
ping is not found