Initial commit

lib/bluster.rb

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+# stdlib
+
+# external
+require 'redis'
+
+# internal
+require 'bluster/bluster'
+require 'bluster/errors'

lib/bluster/bluster.rb

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+class Bluster
+  attr_accessor :objects_path, :redis_host, :redis_port, :last_update_timestamp, :redis
+
+  # Instantiate a new Bluster object.
+  #
+  # objects_path - path to the Nagios objects.cache file 
+  #
+  # Returns a configured Bluster instance.
+  def initialize(objects_path, server)
+    self.objects_path = objects_path
+    self.redis_host = server.split(':').first
+    self.redis_port = server.split(':').last.to_i
+    self.last_update_timestamp = 0
+
+    ensure_object_cache_exists
+    ensure_redis_connection
+  end
+
+  # The list of contact object names.
+  #
+  # Returns an Array of String contact names.
+  def contacts
+    ensure_cache_up_to_date
+    contacts = self.redis.keys("bluster:objects:contact:*")
+    contacts.map! { |r| r.split(":")[3] }
+    contacts.uniq
+  end
+
+  # The configuration details of a contact.
+  #
+  # Returns a Hash of Strings.
+  def get_contact(contact)
+    ensure_cache_up_to_date
+    namespace = "bluster:objects:contact:#{contact}"
+    keys = self.redis.keys("#{namespace}:*")
+    data = {}
+    keys.each { |key|
+      short_key = key.split(":")[4] 
+      data[short_key] = self.redis.get("#{namespace}:#{short_key}")
+    }
+    data
+  end
+
+  private
+
+  # Checks that the provided object cache path exists.
+  #
+  # Returns nothing.
+  def ensure_object_cache_exists
+    if not File.exist? self.objects_path
+      raise ObjectCacheNotFound.new(self.objects_path)
+    end
+  end
+
+  # Ensure that the cache in Redis is up to date
+  #
+  # Returns nothing.
+  def ensure_cache_up_to_date
+    self.last_update_timestamp = self.redis.get("bluster:last_update_timestamp").to_i
+    if self.last_update_timestamp.nil?
+      update_object_cache
+    elsif self.last_update_timestamp != File.new(self.objects_path).mtime.to_i
+      update_object_cache
+    end
+  end
+
+  # Ensure that a working connection to Redis has been established and that
+  # the object cache is up to date.
+  #
+  # Returns nothing.
+  def ensure_redis_connection
+    self.redis = Redis.new(:host => self.redis_host, :port => self.redis_port)
+    ensure_cache_up_to_date
+  rescue Errno::ECONNREFUSED
+    raise RedisConnectionError.new("Unable to connect to redis")
+  end
+
+  # Read the object cache file and store the contents in redis.
+  #
+  # Returns nothing.
+  def update_object_cache
+    in_object = false
+    objects = {}
+    data = {}
+    type = ""
+    File.open(self.objects_path, "r").readlines.each { |line|
+      line = line.strip
+      if line =~ %r{^define (\w+) .*}
+        type = $1
+        in_object = true
+        data = {}
+        if objects[type].nil?
+          objects[type] = []
+        end
+      else
+        if in_object == true
+          if line == "}"
+            in_object = false
+            objects[type] << data
+          else
+            chunks = line.squeeze(' ').split(' ')
+            data[chunks.first] = chunks.last
+          end
+        end
+      end
+    }
+
+    objects["contact"].each { |contact|
+      namespace = "bluster:objects:contact:#{contact['contact_name']}"
+      contact.keys.each { |key|
+        self.redis.set("#{namespace}:#{key}", contact[key]) if key != "contact_name"
+      }
+    }
+
+    self.redis.set("bluster:last_update_timestamp", File.new(self.objects_path).mtime.to_i)
+  end
+end

lib/bluster/errors.rb

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+class Bluster
+  class ObjectCacheNotFound < StandardError
+  end
+
+  class RedisConnectionError < StandardError
+  end
+end