DataStax Ruby Driver

If you're reading this on GitHub, please note that this is the readme for the development version and that somefeatures described here might not yet have been released. You can view the documentation for the latest releasedversion here.A Ruby client driver for Apache Cassandra. This driver works exclusively withthe Cassandra Query Language version 3 (CQL3) and Cassandra's native protocol.Use the Ruby DSE driver forbetter compatibility and support for DataStax Enterprise.Code: https://github.com/datastax/ruby-driverDocs: http://docs.datastax.com/en/developer/ruby-driverJira: https://datastax-oss.atlassian.net/browse/RUBYMailing List: https://groups.google.com/a/lists.datastax.com/forum/#!forum/ruby-driver-userSlack: #datastax-drivers channel at https://academy.datastax.com/slackTwitter: Follow the latest news about DataStax Drivers - @stamhankar999, @avalanche123, @al3xandruThis driver is based on the cql-rb gem by Theo Hultberg and we added support for:Asynchronous executionOne-off, prepared and batch statementsAutomatic peer discovery and cluster metadata with support for change notificationsVarious load-balancing, retry and reconnection policies with ability to write your ownSSL encryptionFlexible and robust error handlingPer-request execution information and tracingConfigurable address resolutionCheck out the slides from Ruby Driver Explained for a detailed overview of the Ruby Driver architecture.CompatibilityThis driver works exclusively with the Cassandra Query Language v3 (CQL3) and Cassandra's native protocol. The current version works with:Apache Cassandra versions 2.1, 2.2, and 3.xDataStax Enterprise 4.8 and above. However, the Ruby DSE driver provides more features and is recommended for use with DataStax Enterprise.Ruby (MRI) 2.2, 2.3, 2.4JRuby 1.7, 9kNote: Rubinius is not supported. MRI 2.0, and 2.1 are not officially supported, but they should work. MRI 1.9.3 is deprecatedand may break in any release after 3.0.Note: Big-endian systems are not supported.Feedback RequestedHelp us focus our efforts! Provide your input on the Ruby Driver Platform and Runtime Survey (we kept it short).Quick startrequire 'cassandra'cluster = Cassandra.cluster # connects to localhost by defaultcluster.each_host do |host| # automatically discovers all peers puts "Host #{host.ip}: id=#{host.id} datacenter=#{host.datacenter} rack=#{host.rack}"endkeyspace = 'system_schema'session = cluster.connect(keyspace) # create session, optionally scoped to a keyspace, to execute queriesfuture = session.execute_async('SELECT keyspace_name, table_name FROM tables') # fully asynchronous apifuture.on_success do |rows| rows.each do |row| puts "The keyspace #{row['keyspace_name']} has a table called #{row['table_name']}" endendfuture.joinNote: The host you specify is just a seed node, the driver will automatically discover all peers in the cluster.Read more:Cassandra.cluster optionsSession#execute_async optionsUsage documentationInstallationInstall via rubygemsgem install cassandra-driverInstall via Gemfilegem 'cassandra-driver'Note: if you want to use compression you should also install snappy or lz4-ruby. Read more about compression.Upgrading from cql-rbSome of the new features added to the driver have unfortunately led to changes in the original cql-rb API.In the examples directory, you can find an example of how to wrap the ruby driver to achieve almost completeinterface parity with cql-rbto assist you with gradual upgrade.If you are upgrading to DataStax Enterprise, use the Ruby DSE driverfor more features and better compatibility.What's new in v3.2This minor release adds support for MRI 2.4.x and also contains a few miscellaneous defect fixes.See the changelog for more information on allchanges in this version and past versions.What's new in v3.1This minor release introduces features and fixes around resiliency, schema metadata, usability, and performance. Oneof the most user-impacting of these is the introduction ofexecution profiles.Execution profiles allow you to group various execution options into a 'profile' and you reference the desiredprofile at execution time. Get the scoophere.What's new in v3.0Features:Add support for Apache Cassandra native protocol v4Add support for smallint, tinyint, date (Cassandra::Date) and time (Cassandra::Time) data types.Include schema metadata for User Defined Functions and User Defined Aggregates.Augment the Cassandra::Table object to expose many more attributes: id, options, keyspace, partition_key, clustering_columns, and clustering_order. This makes it significantly easier to write administration scripts that report various attributes of your schema, which may help to highlight areas for improvement.Include client ip addresses in request traces, only on Cassandra 3.x.Add new retry policy decision Cassandra::Retry::Policy#try_next_host.Support specifying statement idempotence with the new idempotent option when executing.Support sending custom payloads when preparing or executing statements using the new payload option.Expose custom payloads received with responses on server exceptions and Cassandra::Execution::Info instances.Expose server warnings on server exceptions and Cassandra::Execution::Info instances.Add connections_per_local_node, connections_per_remote_node, requests_per_connection cluster configuration options to tune parallel query execution and resource usage.Add Cassandra::Logger class to make it easy for users to enable debug logging in the client.Add protocol_version configuration option to allow the user to force the protocol version to use for communication with nodes.Add support for materialized views and indexes in the schema metadata.Support the ReadError, WriteError, and FunctionCallError Cassandra error responses introduced in Cassandra 2.2.Add support for unset variables in bound statements.Support DSE security (DseAuthenticator, configured for LDAP).Add a timeout option to Cassandra::Future#get.Breaking Changes from 2.x:Cassandra::Future#join is now an alias to Cassandra::Future#get and will raise an error if the future is resolved with one.Default consistency level is now LOCAL_ONE.Enable tcp no-delay by default.Unavailable errors are retried on the next host in the load balancing plan by default.Statement execution no longer retried on timeouts, unless the statement is marked as idempotent in the call to Cassandra::Session#execute* or when creating a Cassandra::Statement object.Cassandra::Statements::Batch#add and Cassandra::Session#execute* signatures have changed in how one specifies query parameters. Specify the query parameters array as the value of the arguments key:batch.add(query, ['val1', 'val2'])# becomesbatch.add(query, arguments: ['val1', 'val2'])batch.add(query, {p1: 'val1'})# becomesbatch.add(query, arguments: {p1: 'val1'})The Datacenter-aware load balancing policy (Cassandra::LoadBalancing::Policies::DCAwareRoundRobin) defaults to usingnodes in the local DC only. In prior releases, the policy would fall back to remote nodes after exhausting local nodes.Specify a positive value (or nil for unlimited) for max_remote_hosts_to_use when initializing the policy to allow remote node use.Unspecified variables in statements previously resulted in an exception. Now they are essentially ignored or treated as null.Code examplesThe DataStax Ruby Driver uses the awesome Cucumber Framework forboth end-to-end, or acceptance, testing and constructing documentation. All of thefeatures supported by the driver have appropriate acceptance tests with easy-to-copy codeexamples in the features/ directory.Running testsIf you don't feel like reading through the following instructions on how to runruby-driver tests, feel free to check out .travis.yml for the entire build code.Check out the driver codebase and install test dependencies:git clone https://github.com/datastax/ruby-driver.gitcd ruby-driverbundle install --without docsInstall ccmRun tests against different versions of Cassandra:CASSANDRA_VERSION=3.1.1 bundle exec cucumber # runs end-to-end tests (or bundle exec rake cucumber)CASSANDRA_VERSION=3.0.0 bundle exec rspec # runs unit tests (or bundle exec rake rspec)CASSANDRA_VERSION=2.1.12 bundle exec rake integration # run integration testsCASSANDRA_VERSION=2.1.12 bundle exec rake test # run both as well as integration testsChangelog & versioningCheck out the releases on GitHub andchangelog. Versionnumbering follows the semantic versioning scheme.Private and experimental APIs, defined as whatever is not in thepublic API documentation, i.e. classes and methods marked as @private, will changewithout warning. If you've been recommended to try an experimental API by the maintainers,please let them know if you depend on that API. Experimental APIs will eventually becomepublic, and knowing how they are used helps in determining their maturity.Prereleases will be stable, in the sense that they will have finished and properly testedfeatures only, but may introduce APIs that will change before the final release. Pleaseuse the prereleases and report bugs, but don't deploy them to production withoutconsulting the maintainers, or doing extensive testing yourself. If you do deploy toproduction please let the maintainers know as this helps in determining the maturity ofthe release.Known bugs & limitationsSpecifying a protocol_version option of 1 or 2 in cluster options will fail with aNoHostsAvailable error rather than a ProtocolError against Cassandra node versions 3.0-3.4.Because the driver reactor is using IO.select, the maximum number of tcp connections allowed is 1024.Because the driver uses IO#write_nonblock, Windows is not supported.Please refer to the usage documentation for more information on common pitfallsContributingFor contributing read CONTRIBUTING.mdCreditsThis driver is based on the original work of Theo Hultbergon cql-rb and adds a series of advanced featuresthat are common across all other DataStax drivers for Apache Cassandra.The development effort to provide an up to date, high performance, fully featured RubyDriver for Apache Cassandra will continue on this project, whilecql-rb has been discontinued.CopyrightCopyright 2013-2017 DataStax, Inc.Licensed under the Apache License, Version 2.0 (the "License"); you may not use this fileexcept in compliance with the License. You may obtain a copy of the License athttp://www.apache.org/licenses/LICENSE-2.0Unless required by applicable law or agreed to in writing, software distributed under theLicense is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,either express or implied. See the License for the specific language governing permissionsand limitations under the License.