can not save logs in login phase

[guazhang]

after one case finished, maybe we need save some logs.
now I try to add login step to do that but I found var TMT_TEST_DATA don't find in the phase.

so could we plan to support the function ?

 login -s execute -c "rhts-submit-log -l /var/log/messages" 

[guazhang@dhcp-131-247 plan]$ tree
.
├── data
│   └── variables.env
├── discover
│   ├── step.yaml
│   └── tests.yaml
├── execute
│   ├── data
│   │   └── guest
│   │       └── default-0
│   │           └── tests
│   │               └── reboot-1
│   │                   ├── ASSERT_STATUSES
│   │                   ├── clbuff
│   │                   ├── cleanup.sh
│   │                   ├── data
│   │                   ├── journal_colored.txt
│   │                   ├── journal.meta
│   │                   ├── journal.txt
│   │                   ├── journal.xml
│   │                   ├── metadata.yaml
│   │                   ├── output.txt
│   │                   ├── PersistentData
│   │                   ├── PHASE_STATUSES
│   │                   ├── TestResults
│   │                   ├── tmt-test-topology.sh
│   │                   └── tmt-test-topology.yaml
│   ├── results.yaml
│   └── step.yaml
├── finish
│   └── step.yaml
├── prepare
│   └── step.yaml
├── provision
│   ├── guests.yaml
│   └── step.yaml
└── report
    └── step.yaml

           00:00:02 pass /tests/reboot (on default-0) [1/1]

        Copy '/var/tmp/tmt/run-005/default/plan/data' from the guest to '/'.
        
        execute task #2: login on default-0
        login: Starting interactive shell
        Push workdir to guest 'storageqe-100.rhts.eng.pek2.redhat.com'.
        Run 'rhts-submit-log -l /var/log/messages' in interactive mode.
        Execute command 'export TMT_PLAN_DATA=/var/tmp/tmt/run-005/default/plan/data; export TMT_PLAN_ENVIRONMENT_FILE=/var/tmp/tmt/run-005/default/plan/data/variables.env; export TMT_TREE=/var/tmp/tmt/run-005/default/plan/tree; export TMT_VERSION=1.30.0; cd /var/tmp/tmt/run-005/default/plan/tree; rhts-submit-log -l /var/log/messages' on guest 'storageqe-100.rhts.eng.pek2.redhat.com'.
Warning: Permanently added 'storageqe-100.rhts.eng.pek2.redhat.com' (ED25519) to the list of known hosts.
/usr/local/bin/rhts-submit-log: line 31: TMT_TEST_DATA: unbound variable
Connection to storageqe-100.rhts.eng.pek2.redhat.com closed.
        login: Interactive shell finished
    
        summary: 1 test executed
    report
    workdir: /var/tmp/tmt/run-005/default/plan/report
        how: display
            pass /tests/reboot
        summary: 1 test passed
    finish

[lukaszachy]

'TMT_TEST_DATA' is available only when test is executed (or login -t). Should we use TMT_PLAN_DATA when https://tmt.readthedocs.io/en/stable/stories/features.html#save-a-log-file is used outside of the test?

Downside is that the risk of name conflicts will be high - we might need to check for that and rename submitted files.