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|
module Spring
class ApplicationManager
attr_reader :pid, :child, :app_env, :spring_env, :status
def initialize(app_env, spring_env)
@app_env = app_env
@spring_env = spring_env
@mutex = Mutex.new
@state = :running
@pid = nil
end
def log(message)
spring_env.log "[application_manager:#{app_env}] #{message}"
end
# We're not using @mutex.synchronize to avoid the weird "<internal:prelude>:10"
# line which messes with backtraces in e.g. rspec
def synchronize
@mutex.lock
yield
ensure
@mutex.unlock
end
def start
start_child
end
def restart
return if @state == :stopping
start_child(true)
end
def alive?
@pid
end
def with_child
synchronize do
if alive?
begin
yield
rescue Errno::ECONNRESET, Errno::EPIPE
# The child has died but has not been collected by the wait thread yet,
# so start a new child and try again.
log "child dead; starting"
start
yield
end
else
log "child not running; starting"
start
yield
end
end
end
# Returns the pid of the process running the command, or nil if the application process died.
def run(client)
with_child do
child.send_io client
child.gets or raise Errno::EPIPE
end
pid = child.gets.to_i
unless pid.zero?
log "got worker pid #{pid}"
pid
end
rescue Errno::ECONNRESET, Errno::EPIPE => e
log "#{e} while reading from child; returning no pid"
nil
ensure
client.close
end
def stop
log "stopping"
@state = :stopping
if pid
Process.kill('TERM', pid)
Process.wait(pid)
end
rescue Errno::ESRCH, Errno::ECHILD
# Don't care
end
private
def start_child(preload = false)
@child, child_socket = UNIXSocket.pair
Bundler.with_original_env do
bundler_dir = File.expand_path("../..", $LOADED_FEATURES.grep(/bundler\/setup\.rb$/).first)
@pid = Process.spawn(
{
"RAILS_ENV" => app_env,
"RACK_ENV" => app_env,
"SPRING_ORIGINAL_ENV" => JSON.dump(Spring::ORIGINAL_ENV),
"SPRING_PRELOAD" => preload ? "1" : "0"
},
"ruby",
*(bundler_dir != RbConfig::CONFIG["rubylibdir"] ? ["-I", bundler_dir] : []),
"-I", File.expand_path("../..", __FILE__),
"-e", "require 'spring/application/boot'",
3 => child_socket,
4 => spring_env.log_file,
)
end
start_wait_thread(pid, child) if child.gets
child_socket.close
end
def start_wait_thread(pid, child)
Process.detach(pid)
Spring.failsafe_thread {
# The recv can raise an ECONNRESET, killing the thread, but that's ok
# as if it does we're no longer interested in the child
loop do
IO.select([child])
break if child.recv(1, Socket::MSG_PEEK).empty?
sleep 0.01
end
log "child #{pid} shutdown"
synchronize {
if @pid == pid
@pid = nil
restart
end
}
}
end
end
end
|
