Check if token file exists on disk

[m0dular]

This commit checks if the admin_token_file exists on disk before reading
it in the retrieve_token() function.

[puppet-community-rangefinder]

influxdb::retrieve_token is a function

that may have no external impact to Forge modules.

This module is declared in 0 of 578 indexed public Puppetfiles.

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Exact matches are those that we can positively identify via namespace and the declaring modules' metadata. Non-namespaced items, such as Puppet 3.x functions, will always be reported as near matches only.

[jarretlavallee]

Does the code that use this function handle a nil/undef result? You may have to return a default string.

[m0dular]

It does, in the sense that it will create a Sensitive[undef] value. That causes the Telegraf override file and the Grafana datasource to use an empty token, which I guess is the expected behavior?

[jarretlavallee]

Sounds good.

[m0dular]

Centos 7 was hung on "Installing PE" for about 40 minutes, so I killed it.