Speed up emulator port allocation #46
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Storing a list of used ports so we don't need to wait for the emulator start command to finish before starting the next emulator.
| @@ -219,17 +211,22 @@ private fun emulatorBinary(args: Commands.Start): String = | |||
| emulator | |||
| } | |||
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| private val usedPorts: MutableList<Int> = mutableListOf() | |||
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This is scary change, I actually used something like this in the beggining, but then figured that it breaks when something else starts emulators outside of Swarmer
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Ok I might be wrong here, if this is just the used ports it should be fine
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I think there is always a small risk if something starts emulators outside of Swarmer that can't be avoided. If a emulator would start after findAvailablePortsForNewEmulator but before Swarmer starts the emulator. Not sure if there is a way to avoid possible port conflicts in that case. But that is a small window so I think we should be fine.
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What if we go the other way around? We can find all ports for required amount of emulators upfront (yes there is a race possible until emulator actually allocates the port, but it's a bit more safe I guess) |
| if (it.isEmpty()) { | ||
| 5554 | ||
| } else { | ||
| synchronized(usedPorts) { |
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I'd use ConcurrentHashMap().toSet() so you have thread-safe MutableSet without need for synchronization
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How would the usage look like? We basically need to read the entire list and then write to it before the next thread is allowed to read it. Not sure if ConcurrentHashMap can do that. But a AtomicInteger might do the trick.
Add test for port allocation
Store a list of used ports so we don't need to wait for the emulator start command to finish before starting the next emulator.