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Mahesh Asolkar 2024-02-04 11:48:23 -08:00
commit 73e6444a00

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cloudflare_dyndns_update.rb Executable file
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#!/usr/bin/env ruby
# -----
#
# Copyright (c) 2024 mahesh
#
# 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.
#
# -----
require 'pp'
require 'optparse'
require 'net/http'
require 'uri'
require 'json'
require 'yaml'
require 'logger'
# ------------------
# Helper Classes
# ------------------
class CloudflareDynDNSUpdater
attr_accessor :options, :myip, :config, :cache
def initialize(options)
@logger = Logger.new(STDOUT)
@options = options
@config = read_config_file
@logger.level = @options[:debug] ? Logger::DEBUG : Logger::INFO
@logger.info($0) { "Starting..." }
@query_info = Hash.new
@cache_updated = false
if @options[:api_key].empty?
@logger.error "Need Cloudflare API key to proceed"
exit 1
end
end
def run()
#
# Load the cache so we know hosts and their IPs were updated
# in the past
#
@cache = read_cache_file
@logger.debug @cache.inspect
#
# Get the Public IP (WAN). We will compare this with the IP
# in the cache to know if the IP has changed and needs to be
# updated in Cloudflare's DNS
#
@myip = get_public_ip
@logger.info "Public IP: #{@myip}"
#
# Query DNS records
#
process_dns
# Write updated cache
if @cache_updated
write_cache_file
end
end
def report()
@logger.info($0) { "Done." }
end
private
#
# Read configuration file, which contains the list of hosts and
# their credentials. Configuration file uses the YAML format
# and has the following template:
#
# -----------
# hosts:
# - host: hostone.com
# zone_id: <cloudflare hostone zone_id>
# - host: hosttwo.com
# zone_id: <cloudflare hosttwo zone_id>
# - ...
# -----------
#
# Default location of the configuration file is:
#
# ~/.cfdyndns.yaml
#
# Alternate location may be provided with [-f|--config_file] option
#
def read_config_file()
if File.exists?(options[:config_file])
return YAML.load_file(options[:config_file])
else
@logger.error "Config file [#{options[:config_file]}] missing!"
end
end
#
# To avoid frequent queries to Cloudflare, store the status of
# latest update to a cache file. Cloudflare is updated only if
# our public IP has changed.
#
# Default location of cache file is:
#
# ~/.cfdyndns.cache
#
# Alternate location may be provided with [-c|--cache_file] option
#
def read_cache_file()
#
# Update to Cloudflare may be forced by forgetting cached
# values. This is controlled by the [-u|--force_update] option
#
if options[:force_update]
if File.exists?(options[:cache_file])
File.delete(options[:cache_file])
end
end
#
# Load the cache file
#
return File.exists?(options[:cache_file]) ? YAML.load_file(options[:cache_file]) : {}
end
#
# Store IPs from current update into cache
#
def write_cache_file()
@logger.debug @cache.inspect
@logger.info "Writing updated cache file"
File.open(options[:cache_file], "w") {|f| f.write(@cache.to_yaml)}
end
#
# Acquire the public IP from an external service
#
def get_public_ip()
return Net::HTTP.get(URI('http://ipinfo.io/ip'))
end
#
# Query Cloudflare for Domains info
#
def process_dns()
#
# Handle each host in the config file at a time
#
@config['hosts'].each {|h|
if @cache[h['host']] && @myip.eql?(@cache[h['host']]['ip'])
@logger.info "Skipping #{h['host']} - Already pointing to #{@myip}"
else
query_sts_good = query_dns(h)
if query_sts_good
update_sts_good = update_dns(h['host'])
end
end
}
end
def query_dns(host)
sts_good = false
url = "https://api.cloudflare.com/client/v4/zones/#{host['zone_id']}/dns_records"
@logger.debug "Querying Cloudflare for host [#{host['host']}] - #{url}"
uri = URI(url)
Net::HTTP.start(uri.host, uri.port, :use_ssl => true) do |http|
request = Net::HTTP::Get.new uri
request.add_field 'Content-Type', 'application/json'
request.add_field 'Authorization', "Bearer #{@options[:api_key]}"
request.add_field 'User-Agent', "#{@options[:user_agent]}"
response = http.request request # Net::HTTPResponse object
sts_good = handle_query(JSON.parse(response.body))
end
return sts_good
end
def handle_query(body)
if body['success']
body['result'].each {|entry|
if entry['type'].eql?('A')
@query_info[entry['name']] = entry
return true
end
}
return false
else
body['errors'].each {|err|
@logger.error "Error status returned #{err['code']}: #{err['message']}"
}
return false
end
end
#
# Update Cloudflare if IP has changed
#
def update_dns(host)
sts_good = false
#
# Handle each host in the config file at a time
#
if @query_info.has_key?(host)
# Use information from query response when possible
q_info = @query_info[host]
url = "https://api.cloudflare.com/client/v4/zones/#{q_info['zone_id']}/dns_records/#{q_info['id']}"
@logger.debug "Updating Cloudflare for host [#{host['host']}] - #{url}"
uri = URI(url)
request_body = {
'type' => q_info['type'],
'name' => q_info['name'],
'content' => @myip
}
@logger.debug request_body.to_json
Net::HTTP.start(uri.host, uri.port, :use_ssl => true) do |http|
request = Net::HTTP::Patch.new uri
request.add_field 'Content-Type', 'application/json'
request.add_field 'Authorization', "Bearer #{@options[:api_key]}"
request.add_field 'User-Agent', "#{@options[:user_agent]}"
request.body = request_body.to_json
response = http.request request # Net::HTTPResponse object
sts_good = handle_update(JSON.parse(response.body))
end
return sts_good
else
@logger.error "Did not find query information for host #{host}"
end
return sts_good
end
def handle_update(body)
if body['success']
entry = body['result']
@logger.info "Successfully updated DNS entry type #{entry['type']} - #{entry['name']} - #{entry['content']}"
@cache[entry['name']] = {'ip' => entry['content']}
@cache_updated = true
return true
else
body['errors'].each {|err|
@logger.error "Error status returned #{err['code']}: #{err['message']}"
}
return false
end
end
end
# -------------------
# Options parsing
# -------------------
#
# Default values of command line options
#
options = {
:config_file => "#{Dir.home}/.cfdyndns.yaml",
:cache_file => "#{Dir.home}/.cfdyndns.cache",
:user_agent => 'HeshApps Cloudflare Dynamic DNS Updater v1.0',
:force_update => false,
:debug => false,
:api_key => ''
}
#
# Get command line options
#
op = OptionParser.new do |opts|
opts.banner = "Usage: cloudflare_dyndns_update.rb [options]"
opts.on("-d", "--debug", "Enable debug messages") do |debug|
options[:debug] = debug
end
opts.on("-u", "--force_update", "Force DNS update") do |force_update|
options[:force_update] = force_update
end
opts.on("-f", "--config_file FILE", "Location of configuration file") do |file|
options[:config_file] = file
end
opts.on("-c", "--cache_file FILE", "Location of cache file") do |file|
options[:cache_file] = file
end
opts.on("-k", "--api_key KEY", "Cloudflare API authorization key") do |key|
options[:api_key] = key
end
opts.on("-h", "--help", "Display this help") do |help|
options[:help] = help
end
end
op.parse!
if options[:help]
puts op.help
exit
end
# ------------------
# Execution part
# ------------------
updater = CloudflareDynDNSUpdater.new(options)
updater.run
updater.report
#
# Mahesh Asolkar, 2024
# vim: ai ts=2 sts=2 et sw=2 filetype=ruby