feat(metrics-sdk): bootstrap views api

[legendecas]

Which problem is this PR solving?

Bootstrap the skeleton of the views API and basic views matching.

Unblocks the metrics stream implementation: provides a way to configure Aggregations.

This PR is not a complete view implementation.

Related: #2592

Short description of the changes

1. Add a ViewRegistry for view matching.
2. Add InstrumentSelector and MeterSelector for metric filtering (wildcard match, exact match, etc.).
3. Add AttributesProcessor interface for altering dimensions.
4. Define the Aggregation interface as configuring how measurements are combined into metrics for Views (Similar to previous Processor.prototype.aggregatorFor).

Type of change

• New feature (non-breaking change which adds functionality)

Checklist:

• Followed the style guidelines of this project
• Unit tests have been added
• Documentation has been updated

[codecov]

Codecov Report

Merging #2625 (f4df716) into main (13acbd3) will decrease coverage by 0.17%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #2625      +/-   ##
==========================================
- Coverage   93.26%   93.08%   -0.18%     
==========================================
  Files         115      123       +8     
  Lines        4645     4761     +116     
  Branches     1036     1061      +25     
==========================================
+ Hits         4332     4432     +100     
- Misses        313      329      +16     

Impacted Files	Coverage Δ
...es/opentelemetry-sdk-metrics-base/src/view/View.ts	100.00% <0.00%> (ø)
...elemetry-sdk-metrics-base/src/view/ViewRegistry.ts	100.00% <0.00%> (ø)
...telemetry-sdk-metrics-base/src/view/Aggregation.ts	71.42% <0.00%> (ø)
.../opentelemetry-sdk-metrics-base/src/Instruments.ts	46.15% <0.00%> (ø)
...lemetry-sdk-metrics-base/src/view/MeterSelector.ts	100.00% <0.00%> (ø)
...ry-sdk-metrics-base/src/view/InstrumentSelector.ts	100.00% <0.00%> (ø)
...y-sdk-metrics-base/src/view/AttributesProcessor.ts	100.00% <0.00%> (ø)
...entelemetry-sdk-metrics-base/src/view/Predicate.ts	100.00% <0.00%> (ø)

[legendecas]

Most of these are whitespace changes: changed 4 spaces indentation to 2 spaces indentation.

[dyladan]

In general I prefer your approach of passing down a shared state class instead of exposing an aggregation function on the meter.

I don't see any handling of the case where there is no view registered. Am I just missing it?

[legendecas]

I don't see any handling of the case where there is no view registered. Am I just missing it?

It's handled in the ViewRegistry.findViews: https://github.com/open-telemetry/opentelemetry-js/pull/2625/files#diff-3891ba0d3add445a01ce7d91f4952f1c9df49a0cb7e9625d615be257f420e7f7R47

And there are test coverages: https://github.com/open-telemetry/opentelemetry-js/pull/2625/files#diff-95e2da7680fa6c3f0dbc3e43fc9ec175ebe45f651e9bfb8e18f31717f2347551R43

[dyladan]

LGTM

[dyladan]

@open-telemetry/javascript-approvers Please take a look at this PR it is holding up other work until it can be merged