Add a control to limit connection reuses #678
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Motivation: Sometimes it can be helpful to limit the number of times a connection can be used before discarding it. AHC has no such support for this at the moment. Modifications: - Add a `maximumUsesPerConnection` configuration option which defaults to `nil` (i.e. no limit). - For HTTP1 we count down uses in the state machine and close the connection if it hits zero. - For HTTP2, each use maps to a stream so we count down remaining uses in the state machine which we combine with max concurrent streams to limit how many streams are available per connection. We also count remaining uses in the HTTP2 idle handler: we treat no remaining uses as receiving a GOAWAY frame and notify the pool which then drains the streams and replaces the connection. Result: Users can control how many times each connection can be used.
dnadoba
reviewed
Apr 11, 2023
| usedStreams += count | ||
| precondition(usedStreams <= maxStreams, "tried to lease a connection which is not available") | ||
| self.state = .active(conn, maxStreams: maxStreams, usedStreams: usedStreams, lastIdle: lastIdle) | ||
| self.state = .active(conn, maxStreams: maxStreams, usedStreams: usedStreams, lastIdle: lastIdle, remainingUses: remainingUses.map { $0 - count }) |
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can we add a precondition for remainingUses >= count
| public var maximumUsesPerConnection: Int? { | ||
| willSet { | ||
| if let newValue = newValue { | ||
| precondition(newValue > 0, "maximumUsesPerConnection must be greater than zero or nil") |
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Lets make this a fatalError so this prints the reason in release builds as well.
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Motivation:
Sometimes it can be helpful to limit the number of times a connection
can be used before discarding it. AHC has no such support for this at
the moment.
Modifications:
maximumUsesPerConnectionconfiguration option which defaultsto
nil(i.e. no limit).connection if it hits zero.
in the state machine which we combine with max concurrent streams to
limit how many streams are available per connection. We also count
remaining uses in the HTTP2 idle handler: we treat no remaining uses
as receiving a GOAWAY frame and notify the pool which then drains the
streams and replaces the connection.
Result:
Users can control how many times each connection can be used.