Module: Puma::SdNotify

Defined in:
lib/puma/sd_notify.rb

Overview

The MIT License

Copyright © 2017-2022 Agis Anastasopoulos

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

This is a copy of github.com/agis/ruby-sdnotify as of commit cca575c The only changes made was “rehoming” it within the Puma module to avoid namespace collisions and applying standard’s code formatting style.

SdNotify is a pure-Ruby implementation of sd_notify(3). It can be used to notify systemd about state changes. Methods of this package are no-op on non-systemd systems (eg. Darwin).

The API maps closely to the original implementation of sd_notify(3), therefore be sure to check the official man pages prior to using SdNotify.

See Also:

Defined Under Namespace

Classes: NotifyError

Constant Summary collapse

READY = 
"READY=1"
RELOADING = 
"RELOADING=1"
STOPPING = 
"STOPPING=1"
STATUS = 
"STATUS="
ERRNO = 
"ERRNO="
MAINPID = 
"MAINPID="
WATCHDOG = 
"WATCHDOG=1"
FDSTORE = 
"FDSTORE=1"

Class Method Summary collapse

Class Method Details

.errno(errno, unset_env = false) ⇒ Object

Parameters:

  • errno (Integer) 


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# File 'lib/puma/sd_notify.rb', line 71

def self.errno(errno, unset_env=false)
  notify("#{ERRNO}#{errno}", unset_env)
end

.fdstore(unset_env = false) ⇒ Object 



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# File 'lib/puma/sd_notify.rb', line 84

def self.fdstore(unset_env=false)
  notify(FDSTORE, unset_env)
end

.mainpid(pid, unset_env = false) ⇒ Object

Parameters:

  • pid (Integer) 


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# File 'lib/puma/sd_notify.rb', line 76

def self.mainpid(pid, unset_env=false)
  notify("#{MAINPID}#{pid}", unset_env)
end

.notify(state, unset_env = false) ⇒ Fixnum?

Notify systemd with the provided state, via the notification socket, if any.

Generally this method will be used indirectly through the other methods of the library.

Parameters:

  • state (String)
  • unset_env (Boolean) (defaults to: false)

Returns:

  • (Fixnum, nil) —

    the number of bytes written to the notification socket or nil if there was no socket to report to (eg. the program wasn’t started by systemd)

Raises:

  • (NotifyError) —

    if there was an error communicating with the systemd socket

See Also:



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# File 'lib/puma/sd_notify.rb', line 132

def self.notify(state, unset_env=false)
  sock = ENV["NOTIFY_SOCKET"]

  return nil if !sock

  ENV.delete("NOTIFY_SOCKET") if unset_env

  begin
    Addrinfo.unix(sock, :DGRAM).connect do |s|
      s.close_on_exec = true
      s.write(state)
    end
  rescue StandardError => e
    raise NotifyError, "#{e.class}: #{e.message}", e.backtrace
  end
end

.ready(unset_env = false) ⇒ Object 



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# File 'lib/puma/sd_notify.rb', line 52

def self.ready(unset_env=false)
  notify(READY, unset_env)
end

.reloading(unset_env = false) ⇒ Object 



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# File 'lib/puma/sd_notify.rb', line 56

def self.reloading(unset_env=false)
  notify(RELOADING, unset_env)
end

.status(status, unset_env = false) ⇒ Object

Parameters:

  • status (String) —

    a custom status string that describes the current state of the service



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# File 'lib/puma/sd_notify.rb', line 66

def self.status(status, unset_env=false)
  notify("#{STATUS}#{status}", unset_env)
end

.stopping(unset_env = false) ⇒ Object 



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# File 'lib/puma/sd_notify.rb', line 60

def self.stopping(unset_env=false)
  notify(STOPPING, unset_env)
end

.watchdog(unset_env = false) ⇒ Object 



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# File 'lib/puma/sd_notify.rb', line 80

def self.watchdog(unset_env=false)
  notify(WATCHDOG, unset_env)
end

.watchdog? ⇒ Boolean

Note:

Unlike sd_watchdog_enabled(3), this method does not mutate the environment.

If the $WATCHDOG_USEC environment variable is set, and the $WATCHDOG_PID variable is unset or set to the PID of the current process

Parameters:

  • true (Boolean) —

    if the service manager expects watchdog keep-alive notification messages to be sent from this process.

Returns:

  • (Boolean) 


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# File 'lib/puma/sd_notify.rb', line 97

def self.watchdog?
  wd_usec = ENV["WATCHDOG_USEC"]
  wd_pid = ENV["WATCHDOG_PID"]

  return false if !wd_usec

  begin
    wd_usec = Integer(wd_usec)
  rescue
    return false
  end

  return false if wd_usec <= 0
  return true if !wd_pid || wd_pid == $$.to_s

  false
end