Add support for using task execution ID fields in log URI templates

[jeevb]

This PR adds a new templating scheme, TaskExecution, that supports the following task execution metadata variables in the log link templates:

{{ .taskID }}
{{ .taskVersion }}
{{ .taskProject }}
{{ .taskDomain }}
{{ .taskRetryAttempt }}
{{ .nodeID }}
{{ .executionName }}
{{ .executionProject }}
{{ .executionDomain }}
{{ .subtaskExecutionIndex }}
{{ .subtaskParentName }}
{{ .subtaskRetryAttempt }}
{{ .subtaskParentRetryAttempt }}

Usage:

plugins:
  logs:
    kubernetes-enabled: false
    templates:
      - displayName: Task Logs
        templateUris:
          - https://flyte.corp.net/console/projects/{{.executionProject}}/domains/{{.executionDomain}}/executions/{{.executionName}}/nodeId/{{.nodeID}}/taskId/{{.taskID}}/attempt/{{.taskRetryAttempt}}/view/logs
        messageFormat: 2
        scheme: TaskExecution
  k8s-array:
    logs:
      config:
        kubernetes-enabled: false
        templates:
          - displayName: Task Logs
            templateUris:
              - https://flyte.corp.net/console/projects/{{.executionProject}}/domains/{{.executionDomain}}/executions/{{.executionName}}/nodeId/{{.nodeID}}/taskId/{{.taskID}}/attempt/{{ .subtaskParentRetryAttempt }}/mappedIndex/{{ .subtaskExecutionIndex }}/mappedAttempt/{{ .subtaskRetryAttempt }}/view/logs
            messageFormat: 2
            scheme: TaskExecution

[codecov]

Codecov Report

Merging #372 (d9c71de) into master (3d2525a) will increase coverage by 1.31%.
The diff coverage is 82.86%.

❗ Current head d9c71de differs from pull request most recent head 06b5e94. Consider uploading reports for the commit 06b5e94 to get more accurate results

@@            Coverage Diff             @@
##           master     #372      +/-   ##
==========================================
+ Coverage   62.92%   64.23%   +1.31%     
==========================================
  Files         153      154       +1     
  Lines       12901    10570    -2331     
==========================================
- Hits         8118     6790    -1328     
+ Misses       4170     3167    -1003     
  Partials      613      613              

Flag	Coverage Δ
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Impacted Files	Coverage Δ
go/tasks/logs/config.go	0.00% <ø> (ø)
...s/pluginmachinery/tasklog/templatescheme_enumer.go	0.00% <0.00%> (ø)
go/tasks/logs/logging_utils.go	89.70% <100.00%> (+1.47%)	⬆️
go/tasks/pluginmachinery/tasklog/template.go	98.60% <100.00%> (+1.30%)	⬆️
go/tasks/plugins/array/k8s/subtask.go	30.35% <100.00%> (-0.14%)	⬇️
go/tasks/plugins/array/k8s/subtask_exec_context.go	83.18% <100.00%> (+3.98%)	⬆️
go/tasks/plugins/k8s/dask/dask.go	86.12% <100.00%> (+3.24%)	⬆️
.../plugins/k8s/kfoperators/common/common_operator.go	70.06% <100.00%> (+6.12%)	⬆️
go/tasks/plugins/k8s/kfoperators/mpi/mpi.go	75.00% <100.00%> (+2.42%)	⬆️
...o/tasks/plugins/k8s/kfoperators/pytorch/pytorch.go	79.86% <100.00%> (+1.17%)	⬆️
... and 3 more

... and 123 files with indirect coverage changes

[fg91]

Nice, thanks, very useful :)
Could you please document these new variables here?