Add initial set of tools

 - rsync-cat: rsync-to-stdout utility
 - gm-lag: displays the current lag of a mirror

4 files changed, 153 insertions, 0 deletions

diff --git a/.rubocop.yml b/.rubocop.yml
new file mode 100644
index 0000000..bc15b92
--- /dev/null
+++ b/.rubocop.yml
@@ -0,0 +1,23 @@
+Style/AsciiComments:
+  Enabled: false
+
+Style/FormatString:
+  Enabled: false
+
+Style/FileName:
+  Enabled: false
+
+Style/Documentation:
+  Enabled: false
+
+Style/PerlBackrefs:
+  Enabled: false
+
+Metrics/LineLength:
+  Max: 120
+
+Metrics/MethodLength:
+  Max: 20
+
+Metrics/ModuleLength:
+  Max: 200
diff --git a/bin/gm-lag b/bin/gm-lag
new file mode 100755
index 0000000..ae81875
--- /dev/null
+++ b/bin/gm-lag
@@ -0,0 +1,27 @@
+#!/usr/bin/env ruby
+# Displays the number of seconds a mirror is lagging behind
+
+require 'optparse'
+require 'time'
+require 'uri'
+require 'net/http'
+require_relative '../lib/mirror_toolkit'
+
+options = {}
+OptionParser.new do |opts|
+  opts.on('-h', '--human', 'Display human times') { |v| options[:human] = v }
+  opts.on('-d', '--distfiles', 'Treat as distfiles mirror') { |v| options[:distfiles] = v }
+  opts.on('-r', '--rsync', 'Treat as rsync mirror') { |v| options[:rsync] = v }
+end.parse!
+
+abort '-d and -r are exclusive.' if options[:distfiles] && options[:rsync]
+
+lag = MirrorToolkit.get_lag(ARGV[0], options[:rsync] ? MirrorToolkit::TYPE_RSYNC : MirrorToolkit::TYPE_DISTFILES)
+
+if lag.nil?
+  puts 'unknown'
+elsif options[:human]
+  puts MirrorToolkit.humanize_seconds(lag)
+else
+  puts lag.to_i
+end
diff --git a/bin/rsync-cat b/bin/rsync-cat
new file mode 100755
index 0000000..e2b7c3c
--- /dev/null
+++ b/bin/rsync-cat
@@ -0,0 +1,14 @@
+#!/bin/bash
+# Prints an rsync file to stdout
+
+me=$(basename $0)
+TMPFILE=$(mktemp /tmp/${me}.XXXXXX) || exit 1
+trap "rm ${TMPFILE}" EXIT
+
+if [ -z "${1}" ]; then
+  echo "Usage: ${0} <rsync url>"
+  exit 1
+fi
+
+rsync -q "${1}" "${TMPFILE}" || exit 1
+cat "${TMPFILE}"
diff --git a/lib/mirror_toolkit.rb b/lib/mirror_toolkit.rb
new file mode 100644
index 0000000..cc53090
--- /dev/null
+++ b/lib/mirror_toolkit.rb
@@ -0,0 +1,89 @@
+require 'open3'
+require 'time'
+require 'net/http'
+
+# Mirror toolkit functionality and other shared stuff
+module MirrorToolkit
+  RSYNC_TIMESTAMP_FILE = '/gentoo-portage/metadata/timestamp'
+  DISTFILES_TIMESTAMP_FILE = '/distfiles/timestamp.mirmon'
+
+  TYPE_RSYNC = 1
+  TYPE_DISTFILES = 2
+
+  module_function
+
+  # Calls `rsync_cat` to fetch a file from rsync
+  def rsync_cat(uri)
+    rsync_cat = File.join(File.dirname(__FILE__), '..', 'bin', 'rsync-cat')
+    stdin, stdout, stderr, wait_thr = Open3.popen3(rsync_cat, uri)
+    stdin.close
+
+    if wait_thr.value == 0
+      return stdout.gets
+    else
+      fail "Rsync call unsuccessful: '#{stderr.gets.chomp}'"
+    end
+  end
+
+  # Fetches a URI from any of the Gentoo mirror types
+  def remote_fetch(url)
+    case url.scheme
+    when 'rsync'
+      rsync_cat(url.to_s)
+    when 'http', 'https', 'ftp'
+      Net::HTTP.get(url)
+    else
+      fail 'Unknown URI scheme.'
+    end
+  end
+
+  # Tries to return a Time object for every kind of timestamp used on Gentoo mirrors
+  def parse_timestamp(ts)
+    if ts.numeric?
+      Time.at(ts.to_i).utc
+    else
+      Time.parse(ts).utc
+    end
+  end
+
+  # Returns a URI object where to find the timestamp for the given url and mirror type.
+  def get_timestamp_url(url, type)
+    mirror = URI(url)
+
+    case mirror.scheme
+    when 'rsync'
+      if type == TYPE_RSYNC
+        mirror.path = MirrorToolkit::RSYNC_TIMESTAMP_FILE
+      elsif type == TYPE_DISTFILES
+        mirror.path += MirrorToolkit::DISTFILES_TIMESTAMP_FILE
+      end
+    when 'http', 'https', 'ftp'
+      mirror.path = MirrorToolkit::DISTFILES_TIMESTAMP_FILE
+    end
+
+    mirror
+  end
+
+  # Returns the number of seconds a mirror is lagging behind, or nil if it cannot be determined.
+  def get_lag(url, type)
+    Time.now.utc - parse_timestamp(remote_fetch(get_timestamp_url(url, type)))
+  rescue
+    nil
+  end
+
+  # Renders seconds as a nice human-printable string
+  def humanize_seconds(secs)
+    [[60, :seconds], [60, :minutes], [24, :hours], [1000, :days]].map do |count, name|
+      if secs > 0
+        secs, n = secs.divmod(count)
+        "#{n.to_i} #{name}"
+      end
+    end.compact.reverse.join(' ')
+  end
+end
+
+class String
+  def numeric?
+    true if Float(self) rescue false
+  end
+end