PS: implement request deduplication

[lukedirtwalker]

Fixes #1858

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This change is 

[scrye]

Reviewed 6 of 6 files at r1.
Reviewable status: all files reviewed, 4 unresolved discussions (waiting on @lukedirtwalker and @kormat)

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go/path_srv/internal/handlers/psdedupe.go, line 42 at r1 (raw file):

}

type psDeduper struct {

Maybe rename this to something like segReqRoundTripper? It's not actually a deduper, as the deduplication happens before its method is called, in the wrapper built below in NewDeduper.

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go/path_srv/internal/handlers/psdedupe.go, line 46 at r1 (raw file):

}

func (pd *psDeduper) segsRequestFunc(ctx context.Context,

If psDeduper is renamed, this can be called something simple like roundTrip.

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go/path_srv/internal/handlers/psdedupe.go, line 62 at r1 (raw file):

}

func (h *segReqHandler) getSegsFromNetwork(ctx context.Context,

This should be moved near segReqHandler's other methods (e.g., underneath fetchAndSaveSegs.

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go/path_srv/internal/handlers/psdedupe.go, line 78 at r1 (raw file):

		return response.Data.(*path_mgmt.SegReply), nil
	case <-ctx.Done():
		return nil, common.NewBasicError("Context done while waiting for Segs",

This wrap fits on one line.

[lukedirtwalker]

Reviewable status: all files reviewed, 5 unresolved discussions (waiting on @lukedirtwalker and @kormat)

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go/path_srv/internal/handlers/psdedupe_test.go, line 48 at r1 (raw file):

		}
		reply := &path_mgmt.SegReply{}
		msger.EXPECT().GetSegs(gomock.Any(), gomock.Any(), gomock.Any(), gomock.Any()).DoAndReturn(

As discussed with @scrye we should no really work against a "real" deduper. We should change deduper to be an interface and work against a mock here. Then we only have to check the public API: 1) Multiple requests should not have a different deduper.
2) A request calls the deduper if it needs to go to the network.

[lukedirtwalker]

Reviewable status: 0 of 5 files reviewed, 4 unresolved discussions (waiting on @scrye, @lukedirtwalker, and @kormat)

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go/path_srv/internal/handlers/psdedupe.go, line 42 at r1 (raw file):

Previously, scrye (Sergiu Costea) wrote…

Maybe rename this to something like segReqRoundTripper? It's not actually a deduper, as the deduplication happens before its method is called, in the wrapper built below in NewDeduper.

I removed the struct. It wasn't really needed just to bind the messenger.

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go/path_srv/internal/handlers/psdedupe.go, line 46 at r1 (raw file):

Previously, scrye (Sergiu Costea) wrote…

If psDeduper is renamed, this can be called something simple like roundTrip.

I inlined this in NewDeduper and call it requestFunc.

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go/path_srv/internal/handlers/psdedupe.go, line 62 at r1 (raw file):

Previously, scrye (Sergiu Costea) wrote…

This should be moved near segReqHandler's other methods (e.g., underneath fetchAndSaveSegs.

Done.

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go/path_srv/internal/handlers/psdedupe.go, line 78 at r1 (raw file):

Previously, scrye (Sergiu Costea) wrote…

This wrap fits on one line.

Done.

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go/path_srv/internal/handlers/psdedupe_test.go, line 48 at r1 (raw file):

Previously, lukedirtwalker (Lukas Vogel) wrote…

As discussed with @scrye we should no really work against a "real" deduper. We should change deduper to be an interface and work against a mock here. Then we only have to check the public API: 1) Multiple requests should not have a different deduper.
2) A request calls the deduper if it needs to go to the network.

Doesn't really make sense. The deduper is already properly tested. So we would just test that we are using it.

[scrye]

Reviewed 6 of 6 files at r2.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @lukedirtwalker and @kormat)