Feature Request - Reuse init command for multiple charts

[allykzam]

The example configuration suggests using an init command for things that require some initial setup, such as getting performance metrics from a database server. In some cases, multiple charts may be fetching data from the same source, so it would be convenient if the sample instance of an init command could be reused somehow. This would be useful for e.g. setting up charts for multiple production servers, separately showing CPU load and RAM usage, where both data sets are coming from the same data source.

[Asherslab]

very much already a thing: https://github.com/sqshq/sampler#variables

[allykzam]

@Asherslab this just reuses the command path and arguments, it doesn't reuse the same instance of the init application. In the example I gave, showing both CPU load and RAM use, using a variable for init still causes two instances of the command to be run, in my case causing two separate connections to the same database server.

[drozdowsky]

Currently using sampler and I agree that global init looks like a must.
But.
Do we really have to have it in sampler? I think this can also can be handled by script/other app (that keeps session)

[Asherslab]

true we could have it elsewhere. but having it in sampler would be nice
i'm sure adding a simple boolean to the variables part to share the same "session" would work fine

[allykzam]

@drozdowsky: for my example of database connections, I did exactly that. I spent a half hour yesterday throwing together a windows service that responds to simple commands over the network. Now my init command for each data point is nc 127.0.0.1 1234, and they all reuse the same database connections.

While this definitely improves things for my company's database servers, it just moves the issue to my local system. Now I have 15 instances of sh -c $localconnection and 15 instances of nc 127.0.0.1 1234 running on my system.

[18829525501]

i agree with you.
usually i monitoring database status with some SELECT cmd, in most situation it is sufficient to create one DB connection, otherwise it will result resourses wasting.