#!/usr/bin/ruby require 'rubygems' require 'pg' require 'yaml' require 'time' require 'fileutils' require 'xml/libxml' require 'zlib' # after this many changes, a changeset will be closed CHANGES_LIMIT = 50000 # this is the scale factor for lat/lon values stored as integers in the database GEO_SCALE = 10000000 ## # changeset class keeps some information about changesets downloaded from the # database - enough to let us know which changesets are closed/open & recently # closed. class Changeset attr_reader :id, :created_at, :closed_at, :num_changes def initialize(row) @id = row['id'].to_i @created_at = Time.parse(row['created_at']) @closed_at = Time.parse(row['closed_at']) @num_changes = row['num_changes'].to_i end def closed?(t) (@closed_at < t) || (@num_changes >= CHANGES_LIMIT) end def open?(t) !closed?(t) end def activity_between?(t1, t2) ((@closed_at >= t1) && (@closed_at < t2)) || ((@created_at >= t1) && (@created_at < t2)) end end ## # state and connections associated with getting changeset data # replicated to a file. class Replicator def initialize(config) @config = YAML.load(File.read(config)) @state = YAML.load(File.read(@config['state_file'])) @conn = PGconn.connect(@config['db']) @now = Time.now.getutc end def open_changesets last_run = @state['last_run'] last_run = (@now - 60) if last_run.nil? @state['last_run'] = @now # pretty much all operations on a changeset will modify its closed_at # time (see rails_port's changeset model). so it is probably enough # for us to look at anything that was closed recently, and filter from # there. @conn .exec("select id, created_at, closed_at, num_changes from changesets where closed_at > ((now() at time zone 'utc') - '1 hour'::interval)") .map { |row| Changeset.new(row) } .select { |cs| cs.activity_between?(last_run, @now) } end # creates an XML file containing the changeset information from the # list of changesets output by open_changesets. def changeset_dump(changesets) doc = XML::Document.new doc.root = XML::Node.new("osm") { 'version' => '0.6', 'generator' => 'replicate_changesets.rb', 'copyright' => "OpenStreetMap and contributors", 'attribution' => "http://www.openstreetmap.org/copyright", 'license' => "http://opendatacommons.org/licenses/odbl/1-0/" } .each { |k, v| doc.root[k] = v } changesets.each do |cs| xml = XML::Node.new("changeset") xml['id'] = cs.id.to_s xml['created_at'] = cs.created_at.getutc.xmlschema xml['closed_at'] = cs.closed_at.getutc.xmlschema if cs.closed?(@now) xml['open'] = cs.open?(@now).to_s xml['num_changes'] = cs.num_changes.to_s res = @conn.exec("select u.id, u.display_name, c.min_lat, c.max_lat, c.min_lon, c.max_lon from users u join changesets c on u.id=c.user_id where c.id=#{cs.id}") xml['user'] = res[0]['display_name'] xml['uid'] = res[0]['id'] unless res[0]['min_lat'].nil? || res[0]['max_lat'].nil? || res[0]['min_lon'].nil? || res[0]['max_lon'].nil? xml['min_lat'] = (res[0]['min_lat'].to_f / GEO_SCALE).to_s xml['max_lat'] = (res[0]['max_lat'].to_f / GEO_SCALE).to_s xml['min_lon'] = (res[0]['min_lon'].to_f / GEO_SCALE).to_s xml['max_lon'] = (res[0]['max_lon'].to_f / GEO_SCALE).to_s end res = @conn.exec("select k, v from changeset_tags where changeset_id=#{cs.id}") res.each do |row| tag = XML::Node.new("tag") tag['k'] = row['k'] tag['v'] = row['v'] xml << tag end doc.root << xml end doc.to_s end # saves new state (including the changeset dump xml) def save! File.open(@config['state_file'], "r") do |fl| fl.flock(File::LOCK_EX) sequence = (@state.key?('sequence') ? @state['sequence'] + 1 : 0) data_file = @config['data_dir'] + format("/%03d/%03d/%03d.osm.gz", sequence / 1000000, (sequence / 1000) % 1000, (sequence % 1000)) tmp_state = @config['state_file'] + ".tmp" tmp_data = "/tmp/changeset_data.osm.tmp" # try and write the files to tmp locations and then # move them into place later, to avoid in-progress # clashes, or people seeing incomplete files. begin FileUtils.mkdir_p(File.dirname(data_file)) Zlib::GzipWriter.open(tmp_data) do |fh| fh.write(changeset_dump(open_changesets)) end @state['sequence'] = sequence File.open(tmp_state, "w") do |fh| fh.write(YAML.dump(@state)) end FileUtils.mv(tmp_data, data_file) FileUtils.mv(tmp_state, @config['state_file']) fl.flock(File::LOCK_UN) rescue STDERR.puts("Error! Couldn't update state.") fl.flock(File::LOCK_UN) raise end end end end rep = Replicator.new(ARGV[0]) rep.save!