Mysql select value check

CHANGELOG.md

@@ -4,6 +4,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 This CHANGELOG follows the format listed [here](https://github.com/sensu-plugins/community/blob/master/HOW_WE_CHANGELOG.md)
 
 ## [Unreleased]
+### Added
+- check-mysql-select-value.rb script (@DrMurx)
 
 ## [2.5.1] - 2018-06-21
 ### Fixed

README.md

@@ -18,6 +18,7 @@
  * bin/check-mysql-threads.rb
  * bin/check-mysql-query-result-count.rb
  * bin/check-mysql-select-count.rb
+ * bin/check-mysql-select-value.rb
  * bin/check-mysql-msr-replication-status.rb
  * bin/metrics-mysql-graphite.rb
  * bin/metrics-mysql-processes.rb
@@ -93,6 +94,11 @@ $ /opt/sensu/embedded/bin/check-mysql-replication-status.rb --host=<SLAVE> --ini
 /opt/sensu/embedded/bin$ /opt/sensu/embedded/bin/ruby check-mysql-select-count.rb --host=localhost --port=3306 --user=collectd --pass=tflypass --socket=/data/mysql.sock --warning 30000 --critical 50000 --query 'SELECT count(*) FROM table t'
 ```
 
+**check-mysql-select-value** example
+```bash
+/opt/sensu/embedded/bin$ /opt/sensu/embedded/bin/ruby check-mysql-select-value.rb --host=localhost --port=3306 --user=collectd --pass=tflypass --socket=/data/mysql.sock --warning 1 --critical 2 --query 'SELECT MyStoredFunction()'
+```
+
 **metrics-mysql-query-result-count** example
 ```bash
 /opt/sensu/embedded/bin$ /opt/sensu/embedded/bin/ruby metrics-mysql-query-result-count.rb --host=localhost --port=3306 --user=collectd --pass=tflypass --socket=/data/mysql.sock --query 'SELECT DISTINCT(t.id) FROM table t where t.failed = true'
@@ -110,6 +116,7 @@ In keeping with the principle of least privilege you should create a new user wi
 | check-mysql-innodb-lock.rb             | `PROCESS`                                                 |
 | check-mysql-query-result-count.rb      | depends on query                                          |
 | check-mysql-select-count.rb            | `SELECT`                                                  |
+| check-mysql-select-value.rb            | `SELECT`                                                  |
 | check-mysql-replication-status.rb      | `SUPER` OR `REPLICATION_CLIENT` (the latter is preferable)|
 | check-mysql-msr-replication-status.rb  | `SELECT`                                                  |
 | check-mysql-status.rb                  | `SELECT`                                                  |

bin/check-mysql-select-value.rb

@@ -0,0 +1,131 @@
+#!/usr/bin/env ruby
+#
+# MySQL Select Count Check
+#
+# Checks the length of a result set from a MySQL query.
+#
+# Copyright 2017 Andrew Thal <athal7@me.com> to check-mysql-query-result-count.rb
+# Modified by Mutsutoshi Yoshimoto <negachov@gmail.com> 2018 to select count(*) version
+# Modified by Jan Kunzmann <jan-github@phobia.de> 2018 to select value version
+#
+# Released under the same terms as Sensu (the MIT license); see LICENSE
+# for details.
+
+require 'sensu-plugin/check/cli'
+require 'mysql'
+require 'inifile'
+
+class MysqlSelectCountCheck < Sensu::Plugin::Check::CLI
+  option :host,
+         short: '-h HOST',
+         long: '--host HOST',
+         description: 'MySQL Host to connect to',
+         required: true
+
+  option :port,
+         short: '-P PORT',
+         long: '--port PORT',
+         description: 'MySQL Port to connect to',
+         proc: proc(&:to_i),
+         default: 3306
+
+  option :username,
+         short: '-u USERNAME',
+         long: '--user USERNAME',
+         description: 'MySQL Username'
+
+  option :password,
+         short: '-p PASSWORD',
+         long: '--pass PASSWORD',
+         description: 'MySQL password'
+
+  option :database,
+         short: '-d DATABASE',
+         long: '--database DATABASE',
+         description: 'MySQL database',
+         required: true
+
+  option :ini,
+         short: '-i',
+         long: '--ini VALUE',
+         description: 'My.cnf ini file'
+
+  option :ini_section,
+         description: 'Section in my.cnf ini file',
+         long: '--ini-section VALUE',
+         default: 'client'
+
+  option :socket,
+         short: '-S SOCKET',
+         long: '--socket SOCKET',
+         description: 'MySQL Unix socket to connect to'
+
+  option :warn,
+         short: '-w VALUE',
+         long: '--warning VALUE',
+         description: 'Warning when query value exceeds threshold',
+         proc: proc(&:to_f),
+         required: true
+
+  option :crit,
+         short: '-c VALUE',
+         long: '--critical VALUE',
+         description: 'Critical when query value exceeds threshold',
+         proc: proc(&:to_f),
+         required: true
+
+  option :query,
+         short: '-q SELECT_VALUE_QUERY',
+         long: '--query SELECT_VALUE_QUERY',
+         description: 'Query to execute',
+         required: true
+
+
+  def run
+    if config[:ini]
+      ini = IniFile.load(config[:ini])
+      section = ini[config[:ini_section]]
+      db_user = section['user']
+      db_pass = section['password']
+    else
+      db_user = config[:username]
+      db_pass = config[:password]
+    end
+
+    db = Mysql.real_connect(config[:host], db_user, db_pass, config[:database], config[:port], config[:socket])
+
+    rs = db.query(config[:query])
+    fields = rs.fetch_fields
+    col_name = fields[0].name.capitalize
+
+    value = rs.fetch_row[0].to_f
+
+    if config[:crit] > config[:warn]
+      beyond = "above"
+      beneath = "below"
+      factor = 1.0
+    else
+      beyond = "below"
+      beneath = "above"
+      factor = -1.0
+    end
+
+    if value * factor >= config[:crit] * factor
+      critical "#{col_name} #{value} is #{beyond} the CRITICAL limit of #{config[:crit]}"
+    elsif value * factor >= config[:warn] * factor
+      warning "#{col_name} #{value} is #{beyond} the WARNING limit of #{config[:warn]}"
+    else
+      ok "#{col_name} #{value} is #{beneath} thresholds"
+    end
+
+  rescue Mysql::Error => e
+    errstr = "Error code: #{e.errno} Error message: #{e.error}"
+    critical "#{errstr} SQLSTATE: #{e.sqlstate}" if e.respond_to?('sqlstate')
+
+  rescue StandardError => e
+    critical "Unhandled exception: #{e}"
+
+  ensure
+    db.close if db
+  end
+end