Add pgpass file and env variables support. (#36)

* Add pgpass file and env variables support.

Default pgpass file path is ~/.pgpass
Supported PG variables:
  * PGHOST
  * PGPORT
  * PGDATABASE
  * PGUSER
  * PGPASSWORD

* Fix parentheses to pass RuboCop checks

* Add usage and known issues

* Read only first line from pgpass file

* Add example with PGPASSWORD env variable

Author: marcinhlybin

README.md

@@ -25,8 +25,85 @@
 
 ## Usage
 
+Use `--help` to see command arguments.
+
+### Sample usage
+
+#### Check if PostgreSQL is alive
+```
+$ check-postgres-alive.rb -d template1 -f /var/lib/postgresql/.pgpass
+CheckPostgres OK: Server version: {"version"=>"PostgreSQL 9.6.3 on x86_64-pc-linux-gnu, compiled by gcc (Debian 4.9.2-10) 4.9.2, 64-bit"}
+```
+
+### Check replication status
+```
+$ check-postgres-replication.rb -m psql1.local -s psql2.local -d template1 -w 5 -c 10
+CheckPostgresReplicationStatus OK: replication delayed by 0.0MB :: master:B0/B4031000 slave:B0/B4031000 m_segbytes:16777216
+```
+
+### Check number of connections
+```
+$ export PGPASSWORD=this-is-secret-password
+$ check-postgres-connections.rb -a -w 80 -c 90 -d template1 -u sensu
+CheckPostgresConnections OK: PostgreSQL connections under threshold: 17%, 174 out of 997 connections
+```
+
+### Default values
+
+| Argument       | Env variable | Value     |
+|----------------|--------------|-----------|
+| -f, --pgpass   | PGPASSFILE   | ~/.pgpass |
+| -h, --hostname | PGHOST       | localhost |
+| -P, --port     | PGPORT       | 5432      |
+| -d, --database | PGDATABASE   | postgres  |
+| -u, --user     | PGUSER       | postgres  |
+| -p, --password | PGPASSWORD   |           |
+
+Options precedence is following:
+1. command line arguments
+1. pgpass file
+1. env variables
+1. defaults
+
+### Pgpass file
+
+When file `~/.pgpass` is found it is used by default. You can also use `-f, --pgpass` command line argument or set `PGPASSFILE` env variable.
+
+File format is:
+
+```
+hostname:port:database:username:password
+```
+
+Only first line is used. If database is set to `*` it is ommited.
+
+You can ovveride `pgpass` values with command line arguments, e.g. `-h` for hostname.
+
 ## Installation
 
-[Installation and Setup](http://sensu-plugins.io/docs/installation_instructions.html)
+```
+gem install sensu-plugins-postgres
+```
+
+See [Installation and Setup](http://sensu-plugins.io/docs/installation_instructions.html) for details.
+
+### Known issues
+
+When using Sensu with `EMBEDDED_RUBY=true` and installing Postgres checks with `/usr/bin/sensu-install -p sensu-plugins-postgres` you might get following error:
+
+```
+ERROR:  Error installing sensu-plugins-postgres:
+	ERROR: Failed to build gem native extension.
+[...]
+checking for PQconnectdb() in -lpq... no
+checking for PQconnectdb() in -llibpq... no
+checking for PQconnectdb() in -lms/libpq... no
+Can't find the PostgreSQL client library (libpq)
+*** extconf.rb failed ***
+```
+
+The reason is that **libssl** library which comes with Sensu is incompatible with **libpq** library installed on your system. There is no easy way to fix it. You might want to install sensu-plugins-postgres globally with `gem install sensu-plugins-postgres`.
+
+Checks are in `/usr/local/bin` directory.
 
 ## Notes

bin/check-postgres-alive.rb

@@ -27,10 +27,17 @@
 #   for details.
 #
 
+require 'sensu-plugins-postgres/pgpass'
 require 'sensu-plugin/check/cli'
 require 'pg'
 
 class CheckPostgres < Sensu::Plugin::Check::CLI
+  option :pgpass,
+         description: 'Pgpass file',
+         short: '-f FILE',
+         long: '--pgpass',
+         default: ENV['PGPASSFILE'] || "#{ENV['HOME']}/.pgpass"
+
   option :user,
          description: 'Postgres User',
          short: '-u USER',
@@ -49,22 +56,23 @@ class CheckPostgres < Sensu::Plugin::Check::CLI
   option :database,
          description: 'Database schema to connect to',
          short: '-d DATABASE',
-         long: '--database DATABASE',
-         default: 'test'
+         long: '--database DATABASE'
 
   option :port,
          description: 'Database port',
          short: '-P PORT',
-         long: '--port PORT',
-         default: 5432
+         long: '--port PORT'
 
   option :timeout,
          description: 'Connection timeout (seconds)',
          short: '-T TIMEOUT',
          long: '--timeout TIMEOUT',
          default: nil
 
+  include Pgpass
+
   def run
+    pgpass
     con = PG.connect(host: config[:hostname],
                      dbname: config[:database],
                      user: config[:user],

bin/check-postgres-connections.rb

@@ -32,10 +32,17 @@
 #   for details.
 #
 
+require 'sensu-plugins-postgres/pgpass'
 require 'sensu-plugin/check/cli'
 require 'pg'
 
 class CheckPostgresConnections < Sensu::Plugin::Check::CLI
+  option :pgpass,
+         description: 'Pgpass file',
+         short: '-f FILE',
+         long: '--pgpass',
+         default: ENV['PGPASSFILE'] || "#{ENV['HOME']}/.pgpass"
+
   option :user,
          description: 'Postgres User',
          short: '-u USER',
@@ -49,20 +56,17 @@ class CheckPostgresConnections < Sensu::Plugin::Check::CLI
   option :hostname,
          description: 'Hostname to login to',
          short: '-h HOST',
-         long: '--hostname HOST',
-         default: 'localhost'
+         long: '--hostname HOST'
 
   option :port,
          description: 'Database port',
          short: '-P PORT',
-         long: '--port PORT',
-         default: 5432
+         long: '--port PORT'
 
   option :database,
          description: 'Database name',
          short: '-d DB',
-         long: '--db DB',
-         default: 'postgres'
+         long: '--db DB'
 
   option :warning,
          description: 'Warning threshold number or % of connections. (default: 200 connections)',
@@ -91,8 +95,11 @@ class CheckPostgresConnections < Sensu::Plugin::Check::CLI
          long: '--timeout TIMEOUT',
          default: nil
 
+  include Pgpass
+
   def run
     begin
+      pgpass
       con = PG.connect(host: config[:hostname],
                        dbname: config[:database],
                        user: config[:user],

bin/check-postgres-query.rb

@@ -29,12 +29,19 @@
 #   for details.
 #
 
+require 'sensu-plugins-postgres/pgpass'
 require 'sensu-plugin/check/cli'
 require 'pg'
 require 'dentaku'
 
 # Check PostgresSQL Query
 class CheckPostgresQuery < Sensu::Plugin::Check::CLI
+  option :pgpass,
+         description: 'Pgpass file',
+         short: '-f FILE',
+         long: '--pgpass',
+         default: ENV['PGPASSFILE'] || "#{ENV['HOME']}/.pgpass"
+
   option :user,
          description: 'Postgres User',
          short: '-u USER',
@@ -48,20 +55,17 @@ class CheckPostgresQuery < Sensu::Plugin::Check::CLI
   option :hostname,
          description: 'Hostname to login to',
          short: '-h HOST',
-         long: '--hostname HOST',
-         default: 'localhost'
+         long: '--hostname HOST'
 
   option :port,
          description: 'Database port',
          short: '-P PORT',
-         long: '--port PORT',
-         default: 5432
+         long: '--port PORT'
 
   option :database,
          description: 'Database name',
          short: '-d DB',
-         long: '--db DB',
-         default: 'postgres'
+         long: '--db DB'
 
   option :query,
          description: 'Database query to execute',
@@ -94,8 +98,11 @@ class CheckPostgresQuery < Sensu::Plugin::Check::CLI
          long: '--timeout TIMEOUT',
          default: nil
 
+  include Pgpass
+
   def run
     begin
+      pgpass
       con = PG.connect(host: config[:hostname],
                        dbname: config[:database],
                        user: config[:user],

bin/check-postgres-replication.rb

@@ -26,10 +26,17 @@
 #   for details.
 #
 
+require 'sensu-plugins-postgres/pgpass'
 require 'sensu-plugin/check/cli'
 require 'pg'
 
 class CheckPostgresReplicationStatus < Sensu::Plugin::Check::CLI
+  option :pgpass,
+         description: 'Pgpass file',
+         short: '-f FILE',
+         long: '--pgpass',
+         default: ENV['PGPASSFILE'] || "#{ENV['HOME']}/.pgpass"
+
   option(:master_host,
          short: '-m',
          long: '--master-host=HOST',
@@ -44,8 +51,7 @@ class CheckPostgresReplicationStatus < Sensu::Plugin::Check::CLI
   option(:port,
          short: '-P',
          long: '--port=PORT',
-         description: 'PostgreSQL port',
-         default: 5432)
+         description: 'PostgreSQL port')
 
   option(:database,
          short: '-d',
@@ -90,6 +96,8 @@ class CheckPostgresReplicationStatus < Sensu::Plugin::Check::CLI
          default: nil,
          description: 'Connection timeout (seconds)')
 
+  include Pgpass
+
   def compute_lag(master, slave, m_segbytes)
     m_segment, m_offset = master.split('/')
     s_segment, s_offset = slave.split('/')
@@ -100,6 +108,7 @@ def run
     ssl_mode = config[:ssl] ? 'require' : 'prefer'
 
     # Establishing connection to the master
+    pgpass
     conn_master = PG.connect(host: config[:master_host],
                              dbname: config[:database],
                              user: config[:user],

bin/metric-postgres-connections.rb

@@ -28,11 +28,18 @@
 #   for details.
 #
 
+require 'sensu-plugins-postgres/pgpass'
 require 'sensu-plugin/metric/cli'
 require 'pg'
 require 'socket'
 
 class PostgresStatsDBMetrics < Sensu::Plugin::Metric::CLI::Graphite
+  option :pgpass,
+         description: 'Pgpass file',
+         short: '-f FILE',
+         long: '--pgpass',
+         default: "#{ENV['HOME']}/.pgpass"
+
   option :user,
          description: 'Postgres User',
          short: '-u USER',
@@ -46,20 +53,17 @@ class PostgresStatsDBMetrics < Sensu::Plugin::Metric::CLI::Graphite
   option :hostname,
          description: 'Hostname to login to',
          short: '-h HOST',
-         long: '--hostname HOST',
-         default: 'localhost'
+         long: '--hostname HOST'
 
   option :port,
          description: 'Database port',
          short: '-P PORT',
-         long: '--port PORT',
-         default: 5432
+         long: '--port PORT'
 
   option :database,
          description: 'Database name',
          short: '-d DB',
-         long: '--db DB',
-         default: 'postgres'
+         long: '--db DB'
 
   option :scheme,
          description: 'Metric naming scheme, text to prepend to $queue_name.$metric',
@@ -72,9 +76,11 @@ class PostgresStatsDBMetrics < Sensu::Plugin::Metric::CLI::Graphite
          long: '--timeout TIMEOUT',
          default: nil
 
+  include Pgpass
+
   def run
     timestamp = Time.now.to_i
-
+    pgpass
     con     = PG.connect(host: config[:hostname],
                          dbname: config[:database],
                          user: config[:user],

bin/metric-postgres-dbsize.rb

@@ -28,11 +28,18 @@
 #   for details.
 #
 
+require 'sensu-plugins-postgres/pgpass'
 require 'sensu-plugin/metric/cli'
 require 'pg'
 require 'socket'
 
 class PostgresStatsDBMetrics < 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',
@@ -46,20 +53,17 @@ class PostgresStatsDBMetrics < Sensu::Plugin::Metric::CLI::Graphite
   option :hostname,
          description: 'Hostname to login to',
          short: '-h HOST',
-         long: '--hostname HOST',
-         default: 'localhost'
+         long: '--hostname HOST'
 
   option :port,
          description: 'Database port',
          short: '-P PORT',
-         long: '--port PORT',
-         default: 5432
+         long: '--port PORT'
 
   option :database,
          description: 'Database name',
          short: '-d DB',
-         long: '--db DB',
-         default: 'postgres'
+         long: '--db DB'
 
   option :scheme,
          description: 'Metric naming scheme, text to prepend to $queue_name.$metric',
@@ -72,9 +76,11 @@ class PostgresStatsDBMetrics < Sensu::Plugin::Metric::CLI::Graphite
          long: '--timeout TIMEOUT',
          default: nil
 
+  include Pgpass
+
   def run
     timestamp = Time.now.to_i
-
+    pgpass
     con     = PG.connect(host: config[:hostname],
                          dbname: config[:database],
                          user: config[:user],