Allow topaz to run as an edge authorizer

[carabasdaniel]

Closes: #110

[github-actions]

Pull Request Test Coverage Report for Build 5787683224

• 203 of 743 (27.32%) changed or added relevant lines in 17 files are covered.
• 31 unchanged lines in 4 files lost coverage.
• Overall coverage decreased (-3.6%) to 31.587%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/testing/engine.go	13	14	92.86%
pkg/cc/config/topaz_config.go	1	3	33.33%
pkg/app/topaz.go	29	33	87.88%
pkg/app/edgedir.go	45	51	88.24%
pkg/app/middlewares/tenant_middleware.go	16	22	72.73%
pkg/app/middlewares/middlewares.go	19	26	73.08%
pkg/app/topaz/wire_gen.go	11	19	57.89%
plugins/noop/plugin.go	0	10	0.0%
plugins/noop/factory.go	0	14	0.0%
cmd/topazd/topaz_run.go	0	15	0.0%

Files with Coverage Reduction	New Missed Lines	%
cmd/topazd/topaz_run.go	1	29.85%
pkg/app/authorizer.go	5	61.11%
decision_log/logger/file/logger.go	12	0%
decision_log/logger/file/config.go	13	0%

Totals
Change from base Build 5627278529:	-3.6%
Covered Lines:	1085
Relevant Lines:	3435

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💛 - Coveralls

[carabasdaniel]

@ronenh Do you think we could maybe switch the middleware handling so it would be service type specific ? Would it make sense to add them to the constructor and expose them through the service type interface for the service host factory ?

[ronenh]

@ronenh Do you think we could maybe switch the middleware handling so it would be service type specific ? Would it make sense to add them to the constructor and expose them through the service type interface for the service host factory ?

I think it depends on what we want to accomplish. On one hand, we want to enforce some uniformity in the middleware we use. It makes sense for the service host to be able to ensure that a well-known set of middleware is configured on all services. That could be part of the service host interface. Maybe it can be constructed with an optional list of grpc.ServerOptions.

The question then is whether we want to give individual services the ability to add their own middleware. But since users can choose to group services on ports in whatever way they choose, a service can never know who else would be affected by middleware that it adds. Unless we have a specific example of where that would be necessary, I'd opt for configuring middleware at the service host level.

[gertd]

I left some suggested changes to be considered