48 lines
1.0 KiB
Plaintext
48 lines
1.0 KiB
Plaintext
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#!/usr/bin/env ruby
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# A sample pre-connect check
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#
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# Warms DNS before connecting to hosts in parallel
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#
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# These environment variables are available:
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# KAMAL_RECORDED_AT
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# KAMAL_PERFORMER
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# KAMAL_VERSION
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# KAMAL_HOSTS
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# KAMAL_ROLE (if set)
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# KAMAL_DESTINATION (if set)
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# KAMAL_RUNTIME
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hosts = ENV["KAMAL_HOSTS"].split(",")
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results = nil
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max = 3
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elapsed = Benchmark.realtime do
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results = hosts.map do |host|
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Thread.new do
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tries = 1
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begin
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Socket.getaddrinfo(host, 0, Socket::AF_UNSPEC, Socket::SOCK_STREAM, nil, Socket::AI_CANONNAME)
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rescue SocketError
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if tries < max
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puts "Retrying DNS warmup: #{host}"
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tries += 1
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sleep rand
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retry
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else
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puts "DNS warmup failed: #{host}"
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host
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end
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end
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tries
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end
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end.map(&:value)
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end
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retries = results.sum - hosts.size
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nopes = results.count { |r| r == max }
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puts "Prewarmed %d DNS lookups in %.2f sec: %d retries, %d failures" % [ hosts.size, elapsed, retries, nopes ]
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