refactor(enginenetx): assign InitialDelay when dialing #1555
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This diff refactors the code generating tactics to mix bridge and DNS tactics, such that we avoid trying all bridge tactics before falling back to DNS tactics. In the event in which the bridge is IP or endpoint blocked, this change makes sure we try using DNS tactics earlier, and, if the DNS is working, this means a faster bootstrap. Based on testing, where I replaced the bridge address with 10.0.0.1, we try DNS tactics after 8 seconds. After the first run, if the DNS tactics are working, we would immediately use them before bridge tactics, since we store information about tactics inside the $OONI_HOME/engine dir. Part of ooni/probe#2704.
Previously, we were only testing with DNS returning error, while now we should also have a test case for when it's working given that we're mixing tactics together now.
Conflicts: internal/enginenetx/bridgespolicy_test.go internal/enginenetx/statspolicy.go
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| return out | ||
| p.maybeRewriteTestHelpersTactics(p.Fallback.LookupTactics(ctx, domain, port)), | ||
| ) |
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Here we're replacing an inline expansion of mixSequentially with a call to mixSequentially.
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Additionally, the tx.InitialDelay is gone because we'll compute that once when dialing.
| tactic := &httpsDialerTactic{ | ||
| Address: addr, | ||
| InitialDelay: happyEyeballsDelay(idx), | ||
| InitialDelay: 0, // set when dialing |
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Here we removed computing the happy-eyeballs delay because we're computing it when dialing.
internal/enginenetx/httpsdialer.go
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| @@ -209,7 +209,7 @@ func (hd *httpsDialer) DialTLSContext(ctx context.Context, network string, endpo | |||
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| // The emitter will emit tactics and then close the channel when done. We spawn 16 workers | |||
| // that handle tactics in parallel and post results on the collector channel. | |||
| emitter := hd.policy.LookupTactics(ctx, hostname, port) | |||
| emitter := httpsFilterTactics(hd.policy.LookupTactics(ctx, hostname, port)) | |||
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This is where we're computing the happy eyeballs delay when dialing.
| } | ||
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| // avoid emitting nil tactics and duplicate tactics | ||
| return filterOnlyKeepUniqueTactics(filterOutNilTactics(mixSequentially( |
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Rather than using maybeEmitTactic here we're using filtering to achieve 2/3 of the original goals, i.e., filtering out nils and only keeping unique tactics. The final original goal, i.e., adding happy-eyeballs delays, is now implemented just once when we're dialing, so there's no point in doing that also here.
bassosimone
changed the title
This diff refactors enginenetx to assign InitialDelay only when dialing. It is pointless to do that before. Also, take advantage of algorithms introduced by #1556 to make the code more compact.
Part of ooni/probe#2704.