Class: Sensu::Client::Socket
- Inherits:
-
EM::Connection
- Object
- EM::Connection
- Sensu::Client::Socket
- Defined in:
- lib/sensu/client/socket.rb
Overview
EventMachine connection handler for the Sensu client“s socket.
The Sensu client listens on localhost, port 3030 (by default), for UDP and TCP traffic. This allows software running on the host to push check results (that may contain metrics) into Sensu, without needing to know anything about Sensu“s internal implementation.
The socket only accepts 7-bit ASCII-encoded data.
Although the Sensu client accepts UDP and TCP traffic, you must be aware of the UDP protocol limitations. Any data you send over UDP must fit in a single datagram and you will not receive a response (no confirmation).
UDP Protocol ==
If the socket receives a message containing whitespace and the string “ping”, it will ignore it.
The socket assumes all other messages will contain a single, complete, JSON hash. The hash must be a valid JSON check result. Deserialization failures will be logged at the ERROR level by the Sensu client, but the sender of the invalid data will not be notified.
TCP Protocol ==
If the socket receives a message containing whitespace and the string “ping”, it will respond with the message “pong”.
The socket assumes any other stream will be a single, complete, JSON hash. A deserialization failure will be logged at the WARN level by the Sensu client and respond with the message “invalid”. An “ok” response indicates the Sensu client successfully received the JSON hash and will publish the check result.
Streams can be of any length. The socket protocol does not require any headers, instead the socket tries to parse everything it has been sent each time a chunk of data arrives. Once the JSON parses successfully, the Sensu client publishes the result. After WATCHDOG_DELAY
(default is 500 msec) since the most recent chunk of data was received, the agent will give up on the sender, and instead respond “invalid” and close the connection.
Defined Under Namespace
Classes: DataError
Constant Summary collapse
- WATCHDOG_DELAY =
The number of seconds that may elapse between chunks of data from a sender before it is considered dead, and the connection is close.
0.5
- MODE_ACCEPT =
ACCEPT mode. Append chunks of data to a buffer and test to see whether the buffer contents are valid JSON.
:ACCEPT
- MODE_REJECT =
REJECT mode. No longer receiving data from sender. Discard chunks of data in this mode, the connection is being closed.
:REJECT
Instance Attribute Summary collapse
-
#logger ⇒ Object
Returns the value of attribute logger.
-
#protocol ⇒ Object
Returns the value of attribute protocol.
-
#settings ⇒ Object
Returns the value of attribute settings.
-
#transport ⇒ Object
Returns the value of attribute transport.
Instance Method Summary collapse
-
#cancel_watchdog ⇒ Object
Cancel the current connection watchdog.
-
#parse_check_result(data) ⇒ Object
Parse a JSON check result.
-
#post_init ⇒ Object
Initialize instance variables that will be used throughout the lifetime of the connection.
-
#process_check_result(check) ⇒ Object
Process a check result.
-
#process_data(data) ⇒ Object
Process the data received.
-
#publish_check_result(check) ⇒ Object
Publish a check result to the Sensu transport.
-
#receive_data(data) ⇒ Object
This method is called whenever data is received.
-
#reset_watchdog ⇒ Object
Reset (or start) the connection watchdog.
-
#respond(data) ⇒ Object
Send a response to the sender, close the connection, and call post_init().
-
#validate_check_result(check) ⇒ Object
Validate check result attributes.
Instance Attribute Details
#logger ⇒ Object
Returns the value of attribute logger.
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# File 'lib/sensu/client/socket.rb', line 52 def logger @logger end |
#protocol ⇒ Object
Returns the value of attribute protocol.
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# File 'lib/sensu/client/socket.rb', line 52 def protocol @protocol end |
#settings ⇒ Object
Returns the value of attribute settings.
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# File 'lib/sensu/client/socket.rb', line 52 def settings @settings end |
#transport ⇒ Object
Returns the value of attribute transport.
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# File 'lib/sensu/client/socket.rb', line 52 def transport @transport end |
Instance Method Details
#cancel_watchdog ⇒ Object
Cancel the current connection watchdog.
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# File 'lib/sensu/client/socket.rb', line 96 def cancel_watchdog if @watchdog @watchdog.cancel end end |
#parse_check_result(data) ⇒ Object
Parse a JSON check result. For UDP, immediately raise a parser error. For TCP, record parser errors, so the connection watchdog
can report them.
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# File 'lib/sensu/client/socket.rb', line 162 def parse_check_result(data) begin check = MultiJson.load(data) cancel_watchdog process_check_result(check) rescue MultiJson::ParseError, ArgumentError => error if @protocol == :tcp @parse_error = error.to_s else raise error end end end |
#post_init ⇒ Object
Initialize instance variables that will be used throughout the lifetime of the connection. This method is called when the network connection has been established, and immediately after responding to a sender.
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# File 'lib/sensu/client/socket.rb', line 75 def post_init @protocol ||= :tcp @data_buffer = "" @parse_error = nil @watchdog = nil @mode = MODE_ACCEPT end |
#process_check_result(check) ⇒ Object
Process a check result. Set check result attribute defaults, validate the attributes, publish the check result to the Sensu transport, and respond to the sender with the message “ok”.
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# File 'lib/sensu/client/socket.rb', line 150 def process_check_result(check) check[:status] ||= 0 validate_check_result(check) publish_check_result(check) respond("ok") end |
#process_data(data) ⇒ Object
Process the data received. This method validates the data encoding, provides ping/pong functionality, and passes potential check results on for further processing.
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# File 'lib/sensu/client/socket.rb', line 181 def process_data(data) if data.bytes.find { |char| char > 0x80 } @logger.warn("socket received non-ascii characters") respond("invalid") elsif data.strip == "ping" @logger.debug("socket received ping") respond("pong") else @logger.debug("socket received data", { :data => data }) begin parse_check_result(data) rescue => error @logger.error("failed to process check result from socket", { :data => data, :error => error.to_s }) respond("invalid") end end end |
#publish_check_result(check) ⇒ Object
Publish a check result to the Sensu transport.
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# File 'lib/sensu/client/socket.rb', line 133 def publish_check_result(check) payload = { :client => @settings[:client][:name], :check => check.merge(:issued => Time.now.to_i) } @logger.info("publishing check result", { :payload => payload }) @transport.publish(:direct, "results", MultiJson.dump(payload)) end |
#receive_data(data) ⇒ Object
This method is called whenever data is received. For UDP, it will only be called once, the original data length can be expected. For TCP, this method may be called several times, data received is buffered. TCP connections require a watchdog
.
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# File 'lib/sensu/client/socket.rb', line 210 def receive_data(data) unless @mode == MODE_REJECT case @protocol when :udp process_data(data) when :tcp if EM.reactor_running? reset_watchdog end @data_buffer << data process_data(@data_buffer) end end end |
#reset_watchdog ⇒ Object
Reset (or start) the connection watchdog.
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# File 'lib/sensu/client/socket.rb', line 103 def reset_watchdog cancel_watchdog @watchdog = EM::Timer.new(WATCHDOG_DELAY) do @mode = MODE_REJECT @logger.warn("discarding data buffer for sender and closing connection", { :data => @data_buffer, :parse_error => @parse_error }) respond("invalid") end end |
#respond(data) ⇒ Object
Send a response to the sender, close the connection, and call post_init().
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# File 'lib/sensu/client/socket.rb', line 87 def respond(data) if @protocol == :tcp send_data(data) close_connection_after_writing end post_init end |
#validate_check_result(check) ⇒ Object
Validate check result attributes.
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# File 'lib/sensu/client/socket.rb', line 118 def validate_check_result(check) unless check[:name] =~ /^[\w\.-]+$/ raise DataError, "check name must be a string and cannot contain spaces or special characters" end unless check[:output].is_a?(String) raise DataError, "check output must be a string" end unless check[:status].is_a?(Integer) raise DataError, "check status must be an integer" end end |