CHANGELOG.md

Unreleased

Added Trident, the new high-level abstraction for intermixing high throughput, stateful stream processing with low-latency distributed querying
Added executor abstraction between workers and tasks. Workers = processes, executors = threads that run many tasks from the same spout or bolt.
Pluggable scheduler (thanks xumingming)
Eliminate explicit storage of task->component in Zookeeper
Number of workers can be dynamically changed at runtime through rebalance command and -n switch
Number of executors for a component can be dynamically changed at runtime through rebalance command and -e switch (multiple -e switches allowed)
Use worker heartbeats instead of task heartbeats (thanks xumingming)
UI performance for topologies with many executors/tasks much faster due to optimized usage of Zookeeper (10x improvement)
Added button to show/hide system stats (e.g., acker component and stream stats) from the Storm UI (thanks xumingming)
Stats are tracked on a per-executor basis instead of per-task basis
Major optimization for unreliable spouts and unanchored tuples (will use far less CPU)
Revamped internals of Storm to use LMAX disruptor for internal queuing. Dramatic reductions in contention and CPU usage.
Numerous micro-optimizations all throughout the codebase to reduce CPU usage.
Optimized internals of Storm to use much fewer threads - two fewer threads per spout and one fewer thread per acker.
Removed error method from task hooks (to be re-added at a later time)
Validate that subscriptions come from valid components and streams, and if it's a field grouping that the schema is correct (thanks xumingming)
MemoryTransactionalSpout now works in cluster mode
Only track errors on a component by component basis to reduce the amount stored in zookeeper (to speed up UI). A side effect of this change is the removal of the task page in the UI.
Add TOPOLOGY-TICK-TUPLE-FREQ-SECS config to have Storm automatically send “tick” tuples to a bolt's execute method coming from the __system component and __tick stream at the configured frequency. Meant to be used as a component-specific configuration.
Upgrade Kryo to v2.17
Tuple is now an interface and is much cleaner. The Clojure DSL helpers have been moved to TupleImpl
Added shared worker resources. Storm provides a shared ExecutorService thread pool by default. The number of threads in the pool can be configured with topology.worker.shared.thread.pool.size
Improve CustomStreamGrouping interface to make it more flexible by providing more information
Enhanced INimbus interface to allow for forced schedulers and better integration with global scheduler
Added assigned method to ISupervisor so it knows exactly what's running and not running
Custom serializers can now have one of four constructors: (), (Kryo), (Class), or (Kryo, Class)
Disallow “:”, “.”, and "" from topology names
Errors in multilang subprocesses that go to stderr will be captured and logged to the worker logs (thanks vinodc)
Workers detect and warn for missing outbound connections from assignment, drop messages for which there's no outbound connection
Zookeeper connection timeout is now configurable (via storm.zookeeper.connection.timeout config)
Storm is now less aggressive about halting process when there are Zookeeper errors, preferring to wait until client calls return exceptions.
Can configure Zookeeper authentication for Storm's Zookeeper clients via “storm.zookeeper.auth.scheme” and “storm.zookeeper.auth.payload” configs
Supervisors only download code for topologies assigned to them
Include task id information in task hooks (thanks velvia)
Use execvp to spawn daemons (replaces the python launcher process) (thanks ept)
Bug fix: Realize task ids when worker heartbeats to supervisor. Some users were hitting deserialization problems here in very rare cases (thanks herberteuler)
Bug fix: Fix bug where a topology's status would get corrupted to true if nimbus is restarted while status is rebalancing

0.7.4

Bug fix: Disallow slashes in topology names since it causes Nimbus to break by affecting local filesystem and zookeeper paths
Bug fix: Prevent slow loading tasks from causing worker timeouts by launching the heartbeat thread before tasks are loaded

0.7.3

Changed debug level of “Failed message” logging to DEBUG
Bug fix: Fixed critical regression in 0.7.2 that could cause workers to timeout to the supervisors or to Nimbus. 0.7.2 moved all system tasks to the same thread, so if one took a long time it would block the other critical tasks. Now different system tasks run on different threads.

0.7.2

NOTE: The change from 0.7.0 in which OutputCollector no longer assumes immutable inputs has been reverted to support optimized sending of tuples to colocated tasks

Messages sent to colocated tasks are sent in-memory, skipping serialization (useful in conjunction with localOrShuffle grouping) (thanks xumingming)
Upgrade to Clojure 1.4 (thanks sorenmacbeth)
Exposed INimbus and ISupervisor interfaces for running Storm on different resource frameworks (like Mesos).
Can override the hostname that supervisors report using “storm.local.hostname” config.
Make request timeout within DRPC server configurable via “drpc.request.timeout.secs”
Added “storm list” command to show running topologies at the command line (thanks xumingming)
Storm UI displays the release version (thanks xumingming)
Added reportError to BasicOutputCollector
Added reportError to BatchOutputCollector
Added close method to OpaqueTransactionalSpout coordinator
Added “storm dev-zookeeper” command for launching a local zookeeper server. Useful for testing a one node Storm cluster locally. Zookeeper dir configured with “dev.zookeeper.path”
Use new style classes for Python multilang adapter (thanks hellp)
Added “storm version” command
Heavily refactored and simplified the supervisor and worker code
Improved error message when duplicate config files found on classpath
Print the host and port of Nimbus when using the storm command line client
Include as much of currently read output as possible when pipe to subprocess is broken in multilang components
Lower supervisor worker start timeout to 120 seconds
More debug logging in supervisor
“nohup” no longer used by supervisor to launch workers (unnecessary)
Throw helpful error message if StormSubmitter used without using storm client script
Add Values class as a default serialization
Bug fix: give absolute piddir to subprocesses (so that relative paths can be used for storm local dir)
Bug fix: Fixed critical bug in transactional topologies where a batch would be considered successful even if the batch didn't finish
Bug fix: Fixed critical bug in opaque transactional topologies that would lead to duplicate messages when using pipelining
Bug fix: Workers will now die properly if a ShellBolt subprocess dies (thanks tomo)
Bug fix: Hide the BasicOutputCollector#getOutputter method, since it shouldn't be a publicly available method
Bug fix: Zookeeper in local mode now always gets an unused port. This will eliminate conflicts with other local mode processes or other Zookeeper instances on a local machine. (thanks xumingming)
Bug fix: Fixed NPE in CoordinatedBolt it tuples emitted, acked, or failed for a request id that has already timed out. (thanks xumingming)
Bug fix: UI no longer errors for topologies with no assigned tasks (thanks xumingming)
Bug fix: emitDirect on SpoutOutputCollector now works
Bug fix: Fixed NPE when giving null parallelism hint for spout in TransactionalTopologyBuilder (thanks xumingming)

0.7.1

Implemented shell spout (thanks tomo)
Shell bolts can now asynchronously emit/ack messages (thanks tomo)
Added hooks for when a tuple is emitted, acked, or failed in bolts or spouts.
Added activate and deactivate lifecycle methods on spouts. Spouts start off deactivated.
Added isReady method to ITransactionalSpout$Coordinator to give the ability to delay the creation of new batches
Generalized CustomStreamGrouping to return the target tasks rather than the indices. Also parameterized custom groupings with TopologyContext. (not backwards compatible)
Added localOrShuffle grouping that will send to tasks in the same worker process if possible, or do a shuffle grouping otherwise.
Removed parameter from TopologyContext#maxTopologyMessageTimeout (simplification).
Storm now automatically sets TOPOLOGY_NAME in the config passed to the bolts and spouts to the name of the topology.
Added TOPOLOGY_AUTO_TASK_HOOKS config to automatically add hooks into every spout/bolt for the topology.
Added ability to override configs at the command line. These config definitions have the highest priority.
Error thrown if invalid (not json-serializable) topology conf used.
bin/storm script can now be symlinked (thanks gabrielgrant)
Socket timeout for DRPCClient is now configurable
Added getThisWorkerPort() method to TopologyContext
Added better error checking in Fields (thanks git2samus)
Improved Clojure DSL to allow destructuring in bolt/spout methods
Added Nimbus stats methods to LocalCluster (thanks KasperMadsen)
Added rebalance, activate, deactivate, and killTopologyWithOpts methods to LocalCluster
Added custom stream groupings to LinearDRPC API
Simplify multilang protocol to use json for all messages (thanks tomoj)
Bug fix: Fixed string encoding in ShellBolt protocol to be UTF-8 (thanks nicoo)
Bug fix: Fixed race condition in FeederSpout that could lead to dropped messages
Bug fix: Quoted arguments with spaces now work properly with storm client script
Bug fix: Workers start properly when topology name has spaces
Bug fix: UI works properly when there are spaces in topology or spout/bolt names (thanks xiaokang)
Bug fix: Tuple$Seq now returns correct count (thanks travisfw)

0.7.0

Transactional topologies: a new higher level abstraction that enables exactly-once messaging semantics for most computations. Documented on the wiki.
Component-specific configurations: Can now set configurations on a per-spout or per-bolt basis.
New batch bolt abstraction that simplifies the processing of batches in DRPC or transactional topologies. A new batch bolt is created per batch and they are automatically cleaned up.
Introduction of base classes for various bolt and spout types. These base classes are in the backtype.storm.topology.base package and provide empty implementations for commonly unused methods
CoordinatedBolt generalized to handle non-linear topologies. This will make it easy to implement a non-linear DRPC topology abstraction.
Can customize the JVM options for Storm UI with new ui.childopts config
BigIntegers are now serializable by default
All bolts/spouts now emit a system stream (id “__system”). Currently it only emits startup events, but may emit other events in the future.
Optimized tuple trees for batch processing in DRPC and transactional topologies. Only the coordination tuples are anchored. OutputCollector#fail still works because CoordinatedBolt will propagate the fail to all other tuples in the batch.
CoordinatedBolt moved to backtype.storm.coordination package
Clojure test framework significantly more composable
Massive internal refactorings and simplifications, including changes to the Thrift definition for storm topologies.
Optimized acking system. Bolts with zero or more than one consumer used to send an additional ack message. Now those are no longer sent.
Changed interface of CustomStreamGrouping to receive a List rather than a Tuple.
Added “storm.zookeeper.retry.times” and “storm.zookeeper.retry.interval” configs (thanks killme2008)
Added “storm help” and “storm help {cmd}” to storm script (thanks kachayev)
Logging now always goes to logs/ in the Storm directory, regardless of where you launched the daemon (thanks haitaoyao)
Improved Clojure DSL: can emit maps and Tuples implement the appropriate interfaces to integrate with Clojure's seq functions (thanks schleyfox)
Added “ui.childopts” config (thanks ddillinger)
Bug fix: OutputCollector no longer assumes immutable inputs [NOTE: this was reverted in 0.7.2 because it conflicts with sending tuples to colocated tasks without serialization]
Bug fix: DRPC topologies now throw a proper error when no DRPC servers are configured instead of NPE (thanks danharvey)
Bug fix: Fix local mode so multiple topologies can be run on one LocalCluster
Bug fix: “storm supervisor” now uses supervisor.childopts instead of nimbus.childopts (thanks ddillinger)
Bug fix: supervisor.childopts and nimbus.childopts can now contain whitespace. Previously only the first token was taken from the string
Bug fix: Make TopologyContext “getThisTaskIndex” and “getComponentTasks” consistent
Bug fix: Fix NoNodeException that would pop up with task heartbeating under heavy load
Bug fix: Catch InterruptedExceptions appropriately in local mode so shutdown always works properly

0.6.2

Automatically delete old files in Nimbus's inbox. Configurable with “nimbus.cleanup.inbox.freq.secs” and “nimbus.inbox.jar.expiration.secs”
Redirect System.out and System.err to log4j
Added “topology.worker.child.opts” config, for topology-configurable worker options.
Use Netflix‘s Curator library for Zookeeper communication. Workers now reconnect to Zookeeper rather than crash when there’s a disconnection.
Bug fix: DRPC server no longer hangs with too many concurrent requests. DPRC server now requires two ports: “drpc.port” and “drpc.invocations.port”
Bug fix: Multilang resources are now extracted from the relevant jar on the classpath when appropriate. Previously an error would be thrown if the resources/ dir was in a jar in local mode.
Bug fix: Fix race condition in unit testing where time simulation fails to detect that Storm cluster is waiting due to threads that are not alive
Bug fix: Fix deadlock in Nimbus that could be triggered by a kill command.

0.6.1

storm client “activate” and “deactivate” commands
storm client “rebalance” command
Nimbus will automatically detect and cleanup corrupt topologies (this would previously give an error of the form “file storm...ser cannot be found”).
“storm” client will not run unless it's being used from a release.
Topology jar path now passed in using a java property rather than an environment variable.
LD_LIBRARY_PATH environment variable is now set on worker processes appropriately.
Replaced jvyaml with snakeyaml. UTF-8 YAML files should now work properly.
Upgraded httpclient, httpcore, and commons-codec dependencies.

0.6.0

New serialization system based on Kryo
Component and stream ids are now strings
Pluggable stream groupings
Storm now chooses an unused port for Zookeeper in local mode instead of crashing when 2181 was in use.
Better support for defining topologies in non-JVM languages. The Thrift structure for topologies now allows you to specify components using a Java class name and a list of arguments to that class's constructor.
Bug fix: errors during the preparation phase of spouts or bolts will be reported to the Storm UI
Bug fix: Fixed bugs related to LinearDRPC topologies where the last bolt implements FinishedCallback
Bug fix: String greater than 64K will now serialize properly
Generalized type of anchors in OutputCollector methods to Collection from List.
Improved logging throughout.
In the “worker.childopts” config, %ID% will be replaced by the worker port.
Significant internal refactorings to clean up the codebase.

0.5.4

LinearDRPCTopologyBuilder, a polished DRPC implementation,
Improved custom serialization support. no longer need to provide “token” ids.
Fallback on Java serialization by default. Can be turned off by setting “topology.fall.back.on.java.serialization” to false.
Improved “storm kill” command. Can override the wait time with “-w” flag.
Display topology status in Storm UI
Changed Thrift namespace to avoid conflicts
Better error messages throughout
Storm UI port is configurable through “ui.port”
Minor improvements to Clojure DSL

0.5.3

Nimbus and supervisor daemons can now share a local dir.
Greatly improved Clojure DSL for creating topologies.
Increased the default timeouts for startup of workers and tasks.
Added the commands “localconfvalue”, “remoteconfvalue”, and “repl” to the storm script.
Better error message when “storm jar” can't find the nimbus host in the configuration.

0.5.2

No longer need any native dependencies to run Storm in local mode. Storm now uses a pure Java messaging system in local mode
Fixed logging configurations so that logging is no longer suppressed when including the Storm release jars on the classpath in local mode.

0.5.1

Changed ISerialization's “accept” interface to not annotate the Class with the generic type
Made Config class implement Map and added helper methods for setting common configs

0.5.0

Initial release!