Feature request: allow test name to be templated by an environment variable

[hagertnl]

This may be difficult to do, but I envision a use case like the following.

Say we are using OSU_Alltoall. Instead of creating a new test for each node count we want to test, we create a test like:

Test = osu_alltoall_gpu_VarNODES

In it's rgt_test_input.ini it has nodes = <obtain_from_environment>, which looks for RGT_NODES.
Then this test ingests the RGT_NODES environment variable and sets the test name to osu_alltoall_gpu_<x>nodes.
A test like this would always require RGT_NODES to be set anyway, so I think not setting a default is a good idea, too.

This would be required for InfluxDB, otherwise you'll have data from all your tests mixed in.

One challenge I foresee is that the test name is needed at logging_start, but I don't recall exactly when logging_start happens, so it's possible we have validated the rgt_test_input.ini file by that point.

[ddietz89]

• Worth trying and see how it works.
• Can we bundle multi-node count/related tests into a single sweep test rather than introducing more variables?