[DatastreamToSpanner] Spanner Exception handling

[darshan-sj]

Cagtegorize Spanner Exceptions into Retryable and Permanent Errors.

Retryable errors will be retried through DLQ, Permanent Errors will not be retried and put into severe/ folder of DLQ.

• SpannerMigrationException with ErrorCodes defined in spanner-common module.
• SpannerExceptionParser (in spanner-common) parses a SpannerException and creates a SpannerMigrationException with appropriate ErrorCode.
• SpannerExceptionClassifier (in datastream-to-spanner) classifies a SpannerMigrationException into Retryable or Permanent error based on the SpannerMigrationException.ErrorCode

[codecov]

Codecov Report

Attention: Patch coverage is 92.70073% with 10 lines in your changes missing coverage. Please review.

Project coverage is 47.18%. Comparing base (40141f5) to head (7ee6bef).
Report is 12 commits behind head on main.

Files with missing lines	Patch %	Lines
.../migrations/exceptions/SpannerExceptionParser.java	88.88%	2 Missing and 4 partials ⚠️
...ort/v2/templates/SpannerTransactionWriterDoFn.java	70.00%	1 Missing and 2 partials ⚠️
.../templates/spanner/SpannerExceptionClassifier.java	88.88%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2185      +/-   ##
============================================
+ Coverage     46.96%   47.18%   +0.21%     
- Complexity     4047     4412     +365     
============================================
  Files           876      879       +3     
  Lines         52194    52366     +172     
  Branches       5502     5529      +27     
============================================
+ Hits          24515    24709     +194     
+ Misses        25921    25893      -28     
- Partials       1758     1764       +6     

Components	Coverage Δ
spanner-templates	69.05% <90.74%> (+0.14%)	⬆️
spanner-import-export	65.72% <ø> (+0.01%)	⬆️
spanner-live-forward-migration	76.86% <90.74%> (+0.35%)	⬆️
spanner-live-reverse-replication	79.06% <93.25%> (+0.28%)	⬆️
spanner-bulk-migration	88.01% <93.25%> (+0.07%)	⬆️

Files with missing lines	Coverage Δ
...he/beam/it/gcp/spanner/SpannerResourceManager.java	80.95% <100.00%> (+4.48%)	⬆️
...grations/exceptions/SpannerMigrationException.java	100.00% <100.00%> (ø)
.../templates/spanner/SpannerExceptionClassifier.java	88.88% <88.88%> (ø)
...ort/v2/templates/SpannerTransactionWriterDoFn.java	51.41% <70.00%> (+1.16%)	⬆️
.../migrations/exceptions/SpannerExceptionParser.java	88.88% <88.88%> (ø)

... and 11 files with indirect coverage changes