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Versions: 10
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Stored size: 1.98 KB
Contents
require "fileutils"
module Racecar
class LivenessProbe
def initialize(message_bus, file_path, max_interval)
@message_bus = message_bus
@file_path = file_path
@max_interval = max_interval
@subscribers = []
end
attr_reader :message_bus, :file_path, :max_interval, :subscribers
private :message_bus, :file_path, :max_interval, :subscribers
def check_liveness_within_interval!
unless liveness_event_within_interval?
$stderr.puts "Racecar healthcheck failed: No liveness within interval #{max_interval}s. Last liveness at #{last_liveness_event_at}, #{elapsed_since_liveness_event} seconds ago."
Process.exit(1)
end
end
def liveness_event_within_interval?
elapsed_since_liveness_event < max_interval
rescue Errno::ENOENT
$stderr.puts "Racecar healthcheck failed: Liveness file not found `#{file_path}`"
Process.exit(1)
end
def install
unless file_path && file_writeable?
raise(
"Liveness probe configuration error: `liveness_probe_file_path` must be set to a writable file path.\n" \
" Set `RACECAR_LIVENESS_PROBE_FILE_PATH` and `RACECAR_LIVENESS_MAX_INTERVAL` environment variables."
)
end
subscribers << message_bus.subscribe("start_main_loop.racecar") do
touch_liveness_file
end
subscribers = message_bus.subscribe("shut_down.racecar") do
delete_liveness_file
end
nil
end
def uninstall
subscribers.each { |s| message_bus.unsubscribe(s) }
end
private
def elapsed_since_liveness_event
Time.now - last_liveness_event_at
end
def last_liveness_event_at
File.mtime(file_path)
end
def touch_liveness_file
FileUtils.touch(file_path)
end
def delete_liveness_file
FileUtils.rm_rf(file_path)
end
def file_writeable?
File.write(file_path, "")
File.unlink(file_path)
true
rescue
false
end
end
end
Version data entries
10 entries across 10 versions & 1 rubygems