Refactoring prometheus metrics and labels

[sanketsudake]

This change mainly fixes few things around router and executor
exposed metrices.

1. We are trying to follow standard in metric names.
2. Lables such as namespace are colliding with kube-prometheus standards
   so they are getting relabled to exported_namespace. Added function prefix
   to resolve this.
3. Also made required changes in canary config Prometheus queries.

Signed-off-by: Sanket Sudake sanketsudake@gmail.com

Description

Router

• Labels changed
  • name to function_name
  • namespace to function_namespace
• Changes affects following metrics exposed by router
  • fission_function_calls_total
  • fission_function_errors_total
  • fission_function_duration_seconds
  • fission_function_overhead_seconds
  • fission_function_response_size_bytes

Executor

• Labels
  • funcname -> function_name
  • funcuid -> function_uid
  • funcaddress -> function_address
• Metrics
  • fission_cold_starts_total -> fission_function_cold_starts_total
  • fission_func_running_seconds_summary -> fission_function_running_seconds
  • fission_func_alive_seconds_summary -> fission_function_alive_seconds
  • fission_func_is_alive -> fission_function_is_alive
  • fission_pod_reaptime_seconds -> fission_function_pod_reaptime_seconds
  • fission_idle_pod_time -> fission_function_idle_pod_time

Reference

prometheus/prometheus#9832

Which issue(s) this PR fixes:

Fixes #

Testing

Checklist:

• I ran tests as well as code linting locally to verify my changes.
• I have done manual verification of my changes, changes working as expected.
• I have added new tests to cover my changes.
• My changes follow contributing guidelines of Fission.
• I have signed all of my commits.

[codecov]

Codecov Report

Merging #2375 (1c80895) into master (10f64a8) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2375   +/-   ##
=======================================
  Coverage   18.75%   18.75%           
=======================================
  Files          56       56           
  Lines        6307     6307           
=======================================
  Hits         1183     1183           
  Misses       5040     5040           
  Partials       84       84           

Flag	Coverage Δ
unittests	18.75% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pkg/router/metrics.go	93.02% <ø> (ø)

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