add external data provider

[sozercan]

Signed-off-by: Rita Zhang rita.z.zhang@gmail.com
Signed-off-by: Sertac Ozercan sozercan@gmail.com

Design doc: https://docs.google.com/document/d/1hPi86jdsCKg8puYT5_s_73mPGExUJeZfyKmvG-XWtPc/edit

[codecov-commenter]

Codecov Report

Merging #134 (c3ff133) into master (f653a9c) will decrease coverage by 0.77%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #134      +/-   ##
==========================================
- Coverage   42.28%   41.51%   -0.78%     
==========================================
  Files          46       52       +6     
  Lines        2980     3122     +142     
==========================================
+ Hits         1260     1296      +36     
- Misses       1329     1435     +106     
  Partials      391      391              

Flag	Coverage Δ
unittests	41.51% <ø> (-0.78%)	⬇️

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

Impacted Files	Coverage Δ
...works/constraint/pkg/client/drivers/local/local.go	48.07% <0.00%> (-8.39%)	⬇️
...pis/externaldata/v1alpha1/zz_generated.deepcopy.go	0.00% <0.00%> (ø)
...t/pkg/apis/externaldata/v1alpha1/provider_types.go	100.00% <0.00%> (ø)
...nt/frameworks/constraint/pkg/externaldata/cache.go	100.00% <0.00%> (ø)
.../frameworks/constraint/pkg/externaldata/request.go	0.00% <0.00%> (ø)
...straint/pkg/apis/externaldata/v1alpha1/register.go	0.00% <0.00%> (ø)
...frameworks/constraint/pkg/externaldata/response.go	0.00% <0.00%> (ø)

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[maxsmythe]

Awesome! Mostly clear cut comments. The thorniest comments are around the Rego function signature and whether we should have a more well-defined wire format.

[maxsmythe]

Just a few questions, nothing major I don't think.

[maxsmythe]

Maybe we should put max retries as part of the invocation of the provider? I could see validation more retry-tolerant than mutation, for example.

[sozercan]

you mean as part of external_data() (only for validation so remove maxretry from provider)? do we want to set up a default value if user doesn't provide this (1?)?

[sozercan]

@maxsmythe any unresolved comments?

[maxsmythe]

Couple small things, but ready to merge after that.

[maxsmythe]

LGTM!