Replaced ping-based healthcheck with net.createConnection #351
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Older ping-based healthcheck had a bunch of problems: * Doesn't work in ipv6-only environment (because of calling `ping`, not `ping6`) * Doesn't work if ICMP is blocked, but TCP is not * Doesn't work as expected if TCP on this exact port is firewalled out * Uses a lot of CPU on process spawning, may cause DoS in clusters with large number of worker processes Healthcheck with net.createConnection seems to be a much simpler and more robust alternative Two test were needed changing: * One was implicitly tied to ping interval; ECONNREFUSED was thrown faster, I've tuned reconnect timeout in test * Another one actually relied upon one of aforementioned problems: setting up server at 127.0.0.1:1234 would mean server is available to ping, but not to TCP connection. In that test, I've used net.listen to actually listen for connections on socket
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Test are faililng on nodejs 4/5 because mocha@^4 uses object destructuring, which isn't supported by those versions of node. Downgrading to mocha@^3 helps |
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@3rd-Eden what do you think? |
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@mapleeit, @kevin-greene-ck, looks like you are maintainers now? |
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Anyone? @3rd-Eden @mapleeit @kevin-greene-ck ? |
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@mutantcornholio @3rd-Eden Any one working to integrate this, we are in environment without ping command, this will help us. |
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I've published fork here: This PR is the only difference in code now |
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Older ping-based healthcheck had a bunch of problems:
ping, notping6).large number of worker processes.
Healthcheck with net.createConnection seems to be a much simpler and
more robust alternative
Two test were needed changing:
I've tuned reconnect timeout in test
setting up server at 127.0.0.1:1234 would mean server is available to
ping, but not to TCP connection. In that test, I've used
net.listen to actually listen for connections on socket