cookbooks/planet/files/default/replication-bin/replicate-changesets

   1 #!/usr/bin/ruby
   2
   3 require 'rubygems'
   4 require 'pg'
   5 require 'yaml'
   6 require 'time'
   7 require 'fileutils'
   8 require 'xml/libxml'
   9 require 'zlib'
  10
  11 # after this many changes, a changeset will be closed
  12 CHANGES_LIMIT = 50000
  13
  14 # this is the scale factor for lat/lon values stored as integers in the database
  15 GEO_SCALE = 10000000
  16
  17 ##
  18 # changeset class keeps some information about changesets downloaded from the
  19 # database - enough to let us know which changesets are closed/open & recently
  20 # closed.
  21 class Changeset
  22   attr_reader :id, :created_at, :closed_at, :num_changes
  23
  24   def initialize(row)
  25     @id = row['id'].to_i
  26     @created_at = Time.parse(row['created_at'])
  27     @closed_at = Time.parse(row['closed_at'])
  28     @num_changes = row['num_changes'].to_i
  29   end
  30
  31   def closed?(t)
  32     (@closed_at < t) || (@num_changes >= CHANGES_LIMIT)
  33   end
  34
  35   def open?(t)
  36     !closed?(t)
  37   end
  38
  39   def activity_between?(t1, t2)
  40     ((@closed_at >= t1) && (@closed_at < t2)) || ((@created_at >= t1) && (@created_at < t2))
  41   end
  42 end
  43
  44 ##
  45 # state and connections associated with getting changeset data
  46 # replicated to a file.
  47 class Replicator
  48   def initialize(config)
  49     @config = YAML.load(File.read(config))
  50     @state = YAML.load(File.read(@config['state_file']))
  51     @conn = PGconn.connect(@config['db'])
  52     @now = Time.now.getutc
  53   end
  54
  55   def open_changesets
  56     last_run = @state['last_run']
  57     last_run = (@now - 60) if last_run.nil?
  58     @state['last_run'] = @now
  59     # pretty much all operations on a changeset will modify its closed_at
  60     # time (see rails_port's changeset model). so it is probably enough
  61     # for us to look at anything that was closed recently, and filter from
  62     # there.
  63     @conn
  64       .exec("select id, created_at, closed_at, num_changes from changesets where closed_at > ((now() at time zone 'utc') - '1 hour'::interval)")
  65       .map { |row| Changeset.new(row) }
  66       .select { |cs| cs.activity_between?(last_run, @now) }
  67   end
  68
  69   # creates an XML file containing the changeset information from the
  70   # list of changesets output by open_changesets.
  71   def changeset_dump(changesets)
  72     doc = XML::Document.new
  73     doc.root = XML::Node.new("osm")
  74     { 'version' => '0.6',
  75       'generator' => 'replicate_changesets.rb',
  76       'copyright' => "OpenStreetMap and contributors",
  77       'attribution' => "http://www.openstreetmap.org/copyright",
  78       'license' => "http://opendatacommons.org/licenses/odbl/1-0/" }
  79       .each { |k, v| doc.root[k] = v }
  80
  81     changesets.each do |cs|
  82       xml = XML::Node.new("changeset")
  83       xml['id'] = cs.id.to_s
  84       xml['created_at'] = cs.created_at.getutc.xmlschema
  85       xml['closed_at'] = cs.closed_at.getutc.xmlschema if cs.closed?(@now)
  86       xml['open'] = cs.open?(@now).to_s
  87       xml['num_changes'] = cs.num_changes.to_s
  88
  89       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}")
  90       xml['user'] = res[0]['display_name']
  91       xml['uid'] = res[0]['id']
  92
  93       unless res[0]['min_lat'].nil? ||
  94              res[0]['max_lat'].nil? ||
  95              res[0]['min_lon'].nil? ||
  96              res[0]['max_lon'].nil?
  97         xml['min_lat'] = (res[0]['min_lat'].to_f / GEO_SCALE).to_s
  98         xml['max_lat'] = (res[0]['max_lat'].to_f / GEO_SCALE).to_s
  99         xml['min_lon'] = (res[0]['min_lon'].to_f / GEO_SCALE).to_s
 100         xml['max_lon'] = (res[0]['max_lon'].to_f / GEO_SCALE).to_s
 101       end
 102
 103       res = @conn.exec("select k, v from changeset_tags where changeset_id=#{cs.id}")
 104       res.each do |row|
 105         tag = XML::Node.new("tag")
 106         tag['k'] = row['k']
 107         tag['v'] = row['v']
 108         xml << tag
 109       end
 110
 111       doc.root << xml
 112     end
 113
 114     doc.to_s
 115   end
 116
 117   # saves new state (including the changeset dump xml)
 118   def save!
 119     File.open(@config['state_file'], "r") do |fl|
 120       fl.flock(File::LOCK_EX)
 121
 122       sequence = (@state.key?('sequence') ? @state['sequence'] + 1 : 0)
 123       data_file = @config['data_dir'] + format("/%03d/%03d/%03d.osm.gz", sequence / 1000000, (sequence / 1000) % 1000, (sequence % 1000))
 124       tmp_state = @config['state_file'] + ".tmp"
 125       tmp_data = "/tmp/changeset_data.osm.tmp"
 126       # try and write the files to tmp locations and then
 127       # move them into place later, to avoid in-progress
 128       # clashes, or people seeing incomplete files.
 129       begin
 130         FileUtils.mkdir_p(File.dirname(data_file))
 131         Zlib::GzipWriter.open(tmp_data) do |fh|
 132           fh.write(changeset_dump(open_changesets))
 133         end
 134         @state['sequence'] = sequence
 135         File.open(tmp_state, "w") do |fh|
 136           fh.write(YAML.dump(@state))
 137         end
 138         FileUtils.mv(tmp_data, data_file)
 139         FileUtils.mv(tmp_state, @config['state_file'])
 140         fl.flock(File::LOCK_UN)
 141
 142       rescue
 143         STDERR.puts("Error! Couldn't update state.")
 144         fl.flock(File::LOCK_UN)
 145         raise
 146       end
 147     end
 148   end
 149 end
 150
 151 rep = Replicator.new(ARGV[0])
 152 rep.save!