Assist in visualizing the PostgreSQL vacuum process

Uuse sensu to aggregate vacuum metrics from the `pg_stat_progress_vacuum` view.

Per https://www.postgresql.org/docs/12/progress-reporting.html#VACUUM-PROGRESS-REPORTING

Author: phumpal

bin/metric-postgres-vaccum.rb

@@ -0,0 +1,124 @@
+#! /usr/bin/env ruby
+# frozen_string_literal: true
+
+# DEPENDENCIES:
+#   gem: sensu-plugin
+#   gem: pg
+#
+# USAGE:
+#   ./metric-postgres-vaccum.rb -u db_user -p db_pass -h db_host -d db
+#
+# NOTES:
+#   Requires PSQL `track_counts` `track_io_timing` for some metrics enabled
+#
+# LICENSE:
+#   Copyright (c) 2020 Airbrake Technologies, Inc <support@airbrake.io>
+#   Author Patrick Humpal <patrick@netvilla.net>
+#   Released under the same terms as Sensu (the MIT license); see LICENSE
+#   for details.
+#
+
+require 'sensu-plugins-postgres/pgpass'
+require 'sensu-plugin/metric/cli'
+require 'pg'
+require 'socket'
+
+class PostgresVacuumDBMetrics < Sensu::Plugin::Metric::CLI::Graphite
+  option :pgpass,
+         description: 'Pgpass file',
+         short: '-f FILE',
+         long: '--pgpass',
+         default: ENV['PGPASSFILE'] || "#{ENV['HOME']}/.pgpass"
+
+  option :user,
+         description: 'Postgres User',
+         short: '-u USER',
+         long: '--user USER'
+
+  option :password,
+         description: 'Postgres Password',
+         short: '-p PASS',
+         long: '--password PASS'
+
+  option :hostname,
+         description: 'Hostname to login to',
+         short: '-h HOST',
+         long: '--hostname HOST'
+
+  option :port,
+         description: 'Database port',
+         short: '-P PORT',
+         long: '--port PORT'
+
+  option :database,
+         description: 'Database to connect on',
+         short: '-d DB',
+         long: '--db DB',
+         default: 'postgres'
+
+  option :all_databases,
+         description: 'Get stats for all available databases',
+         short: '-a',
+         long: '--all-databases',
+         boolean: true,
+         default: false
+
+  option :scheme,
+         description: 'Metric naming scheme, text to prepend to $queue_name.$metric',
+         long: '--scheme SCHEME',
+         default: "#{Socket.gethostname}.postgresql"
+
+  option :timeout,
+         description: 'Connection timeout (seconds)',
+         short: '-T TIMEOUT',
+         long: '--timeout TIMEOUT',
+         default: nil
+
+  include Pgpass
+
+  def phase_mapping(vacuum_phase)
+    ['initializing',
+     'scanning heap',
+     'vacuuming indexes',
+     'vacuuming heap',
+     'cleaning up indexes',
+     'truncating heap',
+     'performing final cleanup'].find_index(vacuum_phase)
+  end
+
+  def run
+    timestamp = Time.now.to_i
+    pgpass
+    con = PG.connect(host: config[:hostname],
+                     dbname: config[:database],
+                     user: config[:user],
+                     password: config[:password],
+                     port: config[:port],
+                     connect_timeout: config[:timeout])
+
+    query = 'SELECT * FROM pg_stat_progress_vacuum'
+    params = []
+    unless config[:all_databases]
+      query += ' WHERE datname = $1'
+      params.push config[:database]
+    end
+
+    con.exec_params(query, params) do |result|
+      result.each do |row|
+        database = row['datname']
+
+        row.each do |key, value|
+          next if %w[datid datname].include?(key)
+
+          if key == 'phase'
+            output "#{config[:scheme]}.vacuum.#{database}.phase", phase_mapping(value).to_s, timestamp
+          else
+            output "#{config[:scheme]}.vacuum.#{database}.#{key}", value.to_s, timestamp
+          end
+        end
+      end
+    end
+
+    ok
+  end
+end