Request tracing

Execution information can be used to access request trace if tracing was enabled.

Background

Given

a running cassandra cluster with schema:

CREATE KEYSPACE simplex WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 3};
USE simplex;
CREATE TABLE songs (
  id uuid PRIMARY KEY,
  title text,
  album text,
  artist text,
  tags set<text>,
  data blob
);
INSERT INTO songs (id, title, album, artist, tags)
VALUES (
   756716f7-2e54-4715-9f00-91dcbea6cf50,
   'La Petite Tonkinoise',
   'Bye Bye Blackbird',
   'Joséphine Baker',
   {'jazz', '2013'})
;
INSERT INTO songs (id, title, album, artist, tags)
VALUES (
   f6071e72-48ec-4fcb-bf3e-379c8a696488,
   'Die Mösch',
   'In Gold',
   'Willi Ostermann',
   {'kölsch', '1996', 'birds'}
);
INSERT INTO songs (id, title, album, artist, tags)
VALUES (
   fbdf82ed-0063-4796-9c7c-a3d4f47b4b25,
   'Memo From Turner',
   'Performance',
   'Mick Jager',
   {'soundtrack', '1991'}
);

tracing is disabled by default

Given

the following example:

require 'cassandra'

cluster   = Cassandra.cluster
session   = cluster.connect("simplex")
execution = session.execute("SELECT * FROM songs").execution_info

at_exit { cluster.close }

if execution.trace
  puts "failure"
else
  puts "success"
end

When

it is executed

Then

its output should contain:

success

tracing is enabled explicitly

Given

the following example:

require 'cassandra'

cluster   = Cassandra.cluster
session   = cluster.connect("simplex")
execution = session.execute("SELECT * FROM songs", :trace => true).execution_info
trace     = execution.trace

at_exit { cluster.close }

puts "coordinator: #{trace.coordinator}"
puts "started at: #{trace.started_at}"
puts "total events: #{trace.events.size}"
puts "request: #{trace.request}"

When

it is executed

Then

its output should match:

coordinator: 127\.0\.0\.(1|2|3)

And

its output should match:

started at: \d{4}\-\d{2}\-\d{2} \d{2}:\d{2}:\d{2} (-|\+)\d{4}

And

its output should match:

total events: \d+

And

its output should contain:

request: Execute CQL3 query