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Object org.apache.spark.streaming.StreamingContext
public class StreamingContext
Main entry point for Spark Streaming functionality. It provides methods used to create
DStream
s from various input sources. It can be either
created by providing a Spark master URL and an appName, or from a org.apache.spark.SparkConf
configuration (see core Spark documentation), or from an existing org.apache.spark.SparkContext.
The associated SparkContext can be accessed using context.sparkContext
. After
creating and transforming DStreams, the streaming computation can be started and stopped
using context.start()
and context.stop()
, respectively.
context.awaitTermination()
allows the current thread to wait for the termination
of the context by stop()
or by an exception.
Constructor Summary | |
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StreamingContext(SparkConf conf,
Duration batchDuration)
Create a StreamingContext by providing the configuration necessary for a new SparkContext. |
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StreamingContext(SparkContext sparkContext,
Duration batchDuration)
Create a StreamingContext using an existing SparkContext. |
|
StreamingContext(String path)
Recreate a StreamingContext from a checkpoint file. |
|
StreamingContext(String path,
org.apache.hadoop.conf.Configuration hadoopConf)
Recreate a StreamingContext from a checkpoint file. |
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StreamingContext(String path,
SparkContext sparkContext)
Recreate a StreamingContext from a checkpoint file using an existing SparkContext. |
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StreamingContext(String master,
String appName,
Duration batchDuration,
String sparkHome,
scala.collection.Seq<String> jars,
scala.collection.Map<String,String> environment)
Create a StreamingContext by providing the details necessary for creating a new SparkContext. |
Method Summary | ||
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actorStream(akka.actor.Props props,
String name,
StorageLevel storageLevel,
akka.actor.SupervisorStrategy supervisorStrategy,
scala.reflect.ClassTag<T> evidence$3)
Create an input stream with any arbitrary user implemented actor receiver. |
|
void |
addStreamingListener(StreamingListener streamingListener)
Add a StreamingListener object for
receiving system events related to streaming. |
|
void |
awaitTermination()
Wait for the execution to stop. |
|
void |
awaitTermination(long timeout)
Deprecated. As of 1.3.0, replaced by awaitTerminationOrTimeout(Long) . |
|
boolean |
awaitTerminationOrTimeout(long timeout)
Wait for the execution to stop. |
|
DStream<byte[]> |
binaryRecordsStream(String directory,
int recordLength)
:: Experimental :: |
|
void |
checkpoint(String directory)
Set the context to periodically checkpoint the DStream operations for driver fault-tolerance. |
|
String |
checkpointDir()
|
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Duration |
checkpointDuration()
|
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SparkConf |
conf()
|
|
SparkEnv |
env()
|
|
|
fileStream(String directory,
scala.reflect.ClassTag<K> evidence$6,
scala.reflect.ClassTag<V> evidence$7,
scala.reflect.ClassTag<F> evidence$8)
Create a input stream that monitors a Hadoop-compatible filesystem for new files and reads them using the given key-value types and input format. |
|
|
fileStream(String directory,
scala.Function1<org.apache.hadoop.fs.Path,Object> filter,
boolean newFilesOnly,
scala.reflect.ClassTag<K> evidence$9,
scala.reflect.ClassTag<V> evidence$10,
scala.reflect.ClassTag<F> evidence$11)
Create a input stream that monitors a Hadoop-compatible filesystem for new files and reads them using the given key-value types and input format. |
|
|
fileStream(String directory,
scala.Function1<org.apache.hadoop.fs.Path,Object> filter,
boolean newFilesOnly,
org.apache.hadoop.conf.Configuration conf,
scala.reflect.ClassTag<K> evidence$12,
scala.reflect.ClassTag<V> evidence$13,
scala.reflect.ClassTag<F> evidence$14)
Create a input stream that monitors a Hadoop-compatible filesystem for new files and reads them using the given key-value types and input format. |
|
static scala.Option<StreamingContext> |
getActive()
:: Experimental :: |
|
static StreamingContext |
getActiveOrCreate(scala.Function0<StreamingContext> creatingFunc)
:: Experimental :: |
|
static StreamingContext |
getActiveOrCreate(String checkpointPath,
scala.Function0<StreamingContext> creatingFunc,
org.apache.hadoop.conf.Configuration hadoopConf,
boolean createOnError)
:: Experimental :: |
|
static StreamingContext |
getOrCreate(String checkpointPath,
scala.Function0<StreamingContext> creatingFunc,
org.apache.hadoop.conf.Configuration hadoopConf,
boolean createOnError)
Either recreate a StreamingContext from checkpoint data or create a new StreamingContext. |
|
StreamingContextState |
getState()
:: DeveloperApi :: |
|
org.apache.spark.streaming.DStreamGraph |
graph()
|
|
boolean |
isCheckpointPresent()
|
|
static scala.Option<String> |
jarOfClass(Class<?> cls)
Find the JAR from which a given class was loaded, to make it easy for users to pass their JARs to StreamingContext. |
|
|
networkStream(Receiver<T> receiver,
scala.reflect.ClassTag<T> evidence$1)
Deprecated. As of 1.0.0", replaced by receiverStream . |
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org.apache.spark.streaming.ui.StreamingJobProgressListener |
progressListener()
|
|
|
queueStream(scala.collection.mutable.Queue<RDD<T>> queue,
boolean oneAtATime,
scala.reflect.ClassTag<T> evidence$15)
Create an input stream from a queue of RDDs. |
|
|
queueStream(scala.collection.mutable.Queue<RDD<T>> queue,
boolean oneAtATime,
RDD<T> defaultRDD,
scala.reflect.ClassTag<T> evidence$16)
Create an input stream from a queue of RDDs. |
|
|
rawSocketStream(String hostname,
int port,
StorageLevel storageLevel,
scala.reflect.ClassTag<T> evidence$5)
Create a input stream from network source hostname:port, where data is received as serialized blocks (serialized using the Spark's serializer) that can be directly pushed into the block manager without deserializing them. |
|
|
receiverStream(Receiver<T> receiver,
scala.reflect.ClassTag<T> evidence$2)
Create an input stream with any arbitrary user implemented receiver. |
|
void |
remember(Duration duration)
Set each DStreams in this context to remember RDDs it generated in the last given duration. |
|
SparkContext |
sc()
|
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org.apache.spark.streaming.scheduler.JobScheduler |
scheduler()
|
|
|
socketStream(String hostname,
int port,
scala.Function1<java.io.InputStream,scala.collection.Iterator<T>> converter,
StorageLevel storageLevel,
scala.reflect.ClassTag<T> evidence$4)
Create a input stream from TCP source hostname:port. |
|
ReceiverInputDStream<String> |
socketTextStream(String hostname,
int port,
StorageLevel storageLevel)
Create a input stream from TCP source hostname:port. |
|
SparkContext |
sparkContext()
Return the associated Spark context |
|
void |
start()
Start the execution of the streams. |
|
void |
stop(boolean stopSparkContext)
Stop the execution of the streams immediately (does not wait for all received data to be processed). |
|
void |
stop(boolean stopSparkContext,
boolean stopGracefully)
Stop the execution of the streams, with option of ensuring all received data has been processed. |
|
DStream<String> |
textFileStream(String directory)
Create a input stream that monitors a Hadoop-compatible filesystem for new files and reads them as text files (using key as LongWritable, value as Text and input format as TextInputFormat). |
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static
|
toPairDStreamFunctions(DStream<scala.Tuple2<K,V>> stream,
scala.reflect.ClassTag<K> kt,
scala.reflect.ClassTag<V> vt,
scala.math.Ordering<K> ord)
Deprecated. As of 1.3.0, replaced by implicit functions in the DStream companion object. This is kept here only for backward compatibility. |
|
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transform(scala.collection.Seq<DStream<?>> dstreams,
scala.Function2<scala.collection.Seq<RDD<?>>,Time,RDD<T>> transformFunc,
scala.reflect.ClassTag<T> evidence$18)
Create a new DStream in which each RDD is generated by applying a function on RDDs of the DStreams. |
|
scala.Option<org.apache.spark.streaming.ui.StreamingTab> |
uiTab()
|
|
|
union(scala.collection.Seq<DStream<T>> streams,
scala.reflect.ClassTag<T> evidence$17)
Create a unified DStream from multiple DStreams of the same type and same slide duration. |
|
org.apache.spark.streaming.ContextWaiter |
waiter()
|
Methods inherited from class Object |
---|
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Methods inherited from interface org.apache.spark.Logging |
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initializeIfNecessary, initializeLogging, isTraceEnabled, log_, log, logDebug, logDebug, logError, logError, logInfo, logInfo, logName, logTrace, logTrace, logWarning, logWarning |
Constructor Detail |
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public StreamingContext(SparkContext sparkContext, Duration batchDuration)
sparkContext
- existing SparkContextbatchDuration
- the time interval at which streaming data will be divided into batchespublic StreamingContext(SparkConf conf, Duration batchDuration)
conf
- a org.apache.spark.SparkConf object specifying Spark parametersbatchDuration
- the time interval at which streaming data will be divided into batchespublic StreamingContext(String master, String appName, Duration batchDuration, String sparkHome, scala.collection.Seq<String> jars, scala.collection.Map<String,String> environment)
master
- cluster URL to connect to (e.g. mesos://host:port, spark://host:port, local[4]).appName
- a name for your job, to display on the cluster web UIbatchDuration
- the time interval at which streaming data will be divided into batchessparkHome
- (undocumented)jars
- (undocumented)environment
- (undocumented)public StreamingContext(String path, org.apache.hadoop.conf.Configuration hadoopConf)
path
- Path to the directory that was specified as the checkpoint directoryhadoopConf
- Optional, configuration object if necessary for reading from
HDFS compatible filesystemspublic StreamingContext(String path)
path
- Path to the directory that was specified as the checkpoint directorypublic StreamingContext(String path, SparkContext sparkContext)
path
- Path to the directory that was specified as the checkpoint directorysparkContext
- Existing SparkContextMethod Detail |
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public static scala.Option<StreamingContext> getActive()
Get the currently active context, if there is one. Active means started but not stopped.
public static <K,V> PairDStreamFunctions<K,V> toPairDStreamFunctions(DStream<scala.Tuple2<K,V>> stream, scala.reflect.ClassTag<K> kt, scala.reflect.ClassTag<V> vt, scala.math.Ordering<K> ord)
stream
- (undocumented)kt
- (undocumented)vt
- (undocumented)ord
- (undocumented)
public static StreamingContext getActiveOrCreate(scala.Function0<StreamingContext> creatingFunc)
Either return the "active" StreamingContext (that is, started but not stopped), or create a new StreamingContext that is
creatingFunc
- Function to create a new StreamingContext
public static StreamingContext getActiveOrCreate(String checkpointPath, scala.Function0<StreamingContext> creatingFunc, org.apache.hadoop.conf.Configuration hadoopConf, boolean createOnError)
Either get the currently active StreamingContext (that is, started but not stopped),
OR recreate a StreamingContext from checkpoint data in the given path. If checkpoint data
does not exist in the provided, then create a new StreamingContext by calling the provided
creatingFunc
.
checkpointPath
- Checkpoint directory used in an earlier StreamingContext programcreatingFunc
- Function to create a new StreamingContexthadoopConf
- Optional Hadoop configuration if necessary for reading from the
file systemcreateOnError
- Optional, whether to create a new StreamingContext if there is an
error in reading checkpoint data. By default, an exception will be
thrown on error.
public static StreamingContext getOrCreate(String checkpointPath, scala.Function0<StreamingContext> creatingFunc, org.apache.hadoop.conf.Configuration hadoopConf, boolean createOnError)
checkpointPath
, then StreamingContext will be
recreated from the checkpoint data. If the data does not exist, then the StreamingContext
will be created by called the provided creatingFunc
.
checkpointPath
- Checkpoint directory used in an earlier StreamingContext programcreatingFunc
- Function to create a new StreamingContexthadoopConf
- Optional Hadoop configuration if necessary for reading from the
file systemcreateOnError
- Optional, whether to create a new StreamingContext if there is an
error in reading checkpoint data. By default, an exception will be
thrown on error.
public static scala.Option<String> jarOfClass(Class<?> cls)
cls
- (undocumented)
public boolean isCheckpointPresent()
public SparkContext sc()
public SparkConf conf()
public SparkEnv env()
public org.apache.spark.streaming.DStreamGraph graph()
public String checkpointDir()
public Duration checkpointDuration()
public org.apache.spark.streaming.scheduler.JobScheduler scheduler()
public org.apache.spark.streaming.ContextWaiter waiter()
public org.apache.spark.streaming.ui.StreamingJobProgressListener progressListener()
public scala.Option<org.apache.spark.streaming.ui.StreamingTab> uiTab()
public SparkContext sparkContext()
public void remember(Duration duration)
duration
- Minimum duration that each DStream should remember its RDDspublic void checkpoint(String directory)
directory
- HDFS-compatible directory where the checkpoint data will be reliably stored.
Note that this must be a fault-tolerant file system like HDFS forpublic <T> ReceiverInputDStream<T> networkStream(Receiver<T> receiver, scala.reflect.ClassTag<T> evidence$1)
receiverStream
.
receiver
- Custom implementation of Receiver
evidence$1
- (undocumented)
public <T> ReceiverInputDStream<T> receiverStream(Receiver<T> receiver, scala.reflect.ClassTag<T> evidence$2)
receiver
- Custom implementation of Receiverevidence$2
- (undocumented)
public <T> ReceiverInputDStream<T> actorStream(akka.actor.Props props, String name, StorageLevel storageLevel, akka.actor.SupervisorStrategy supervisorStrategy, scala.reflect.ClassTag<T> evidence$3)
props
- Props object defining creation of the actorname
- Name of the actorstorageLevel
- RDD storage level (default: StorageLevel.MEMORY_AND_DISK_SER_2)
supervisorStrategy
- (undocumented)evidence$3
- (undocumented)
public ReceiverInputDStream<String> socketTextStream(String hostname, int port, StorageLevel storageLevel)
\n
delimited
lines.
hostname
- Hostname to connect to for receiving dataport
- Port to connect to for receiving datastorageLevel
- Storage level to use for storing the received objects
(default: StorageLevel.MEMORY_AND_DISK_SER_2)
public <T> ReceiverInputDStream<T> socketStream(String hostname, int port, scala.Function1<java.io.InputStream,scala.collection.Iterator<T>> converter, StorageLevel storageLevel, scala.reflect.ClassTag<T> evidence$4)
hostname
- Hostname to connect to for receiving dataport
- Port to connect to for receiving dataconverter
- Function to convert the byte stream to objectsstorageLevel
- Storage level to use for storing the received objectsevidence$4
- (undocumented)
public <T> ReceiverInputDStream<T> rawSocketStream(String hostname, int port, StorageLevel storageLevel, scala.reflect.ClassTag<T> evidence$5)
hostname
- Hostname to connect to for receiving dataport
- Port to connect to for receiving datastorageLevel
- Storage level to use for storing the received objects
(default: StorageLevel.MEMORY_AND_DISK_SER_2)evidence$5
- (undocumented)
public <K,V,F extends org.apache.hadoop.mapreduce.InputFormat<K,V>> InputDStream<scala.Tuple2<K,V>> fileStream(String directory, scala.reflect.ClassTag<K> evidence$6, scala.reflect.ClassTag<V> evidence$7, scala.reflect.ClassTag<F> evidence$8)
directory
- HDFS directory to monitor for new fileevidence$6
- (undocumented)evidence$7
- (undocumented)evidence$8
- (undocumented)
public <K,V,F extends org.apache.hadoop.mapreduce.InputFormat<K,V>> InputDStream<scala.Tuple2<K,V>> fileStream(String directory, scala.Function1<org.apache.hadoop.fs.Path,Object> filter, boolean newFilesOnly, scala.reflect.ClassTag<K> evidence$9, scala.reflect.ClassTag<V> evidence$10, scala.reflect.ClassTag<F> evidence$11)
directory
- HDFS directory to monitor for new filefilter
- Function to filter paths to processnewFilesOnly
- Should process only new files and ignore existing files in the directoryevidence$9
- (undocumented)evidence$10
- (undocumented)evidence$11
- (undocumented)
public <K,V,F extends org.apache.hadoop.mapreduce.InputFormat<K,V>> InputDStream<scala.Tuple2<K,V>> fileStream(String directory, scala.Function1<org.apache.hadoop.fs.Path,Object> filter, boolean newFilesOnly, org.apache.hadoop.conf.Configuration conf, scala.reflect.ClassTag<K> evidence$12, scala.reflect.ClassTag<V> evidence$13, scala.reflect.ClassTag<F> evidence$14)
directory
- HDFS directory to monitor for new filefilter
- Function to filter paths to processnewFilesOnly
- Should process only new files and ignore existing files in the directoryconf
- Hadoop configurationevidence$12
- (undocumented)evidence$13
- (undocumented)evidence$14
- (undocumented)
public DStream<String> textFileStream(String directory)
directory
- HDFS directory to monitor for new file
public DStream<byte[]> binaryRecordsStream(String directory, int recordLength)
Create an input stream that monitors a Hadoop-compatible filesystem for new files and reads them as flat binary files, assuming a fixed length per record, generating one byte array per record. Files must be written to the monitored directory by "moving" them from another location within the same file system. File names starting with . are ignored.
'''Note:''' We ensure that the byte array for each record in the resulting RDDs of the DStream has the provided record length.
directory
- HDFS directory to monitor for new filerecordLength
- length of each record in bytes
public <T> InputDStream<T> queueStream(scala.collection.mutable.Queue<RDD<T>> queue, boolean oneAtATime, scala.reflect.ClassTag<T> evidence$15)
NOTE: Arbitrary RDDs can be added to queueStream
, there is no way to recover data of
those RDDs, so queueStream
doesn't support checkpointing.
queue
- Queue of RDDsoneAtATime
- Whether only one RDD should be consumed from the queue in every intervalevidence$15
- (undocumented)
public <T> InputDStream<T> queueStream(scala.collection.mutable.Queue<RDD<T>> queue, boolean oneAtATime, RDD<T> defaultRDD, scala.reflect.ClassTag<T> evidence$16)
NOTE: Arbitrary RDDs can be added to queueStream
, there is no way to recover data of
those RDDs, so queueStream
doesn't support checkpointing.
queue
- Queue of RDDsoneAtATime
- Whether only one RDD should be consumed from the queue in every intervaldefaultRDD
- Default RDD is returned by the DStream when the queue is empty.
Set as null if no RDD should be returned when emptyevidence$16
- (undocumented)
public <T> DStream<T> union(scala.collection.Seq<DStream<T>> streams, scala.reflect.ClassTag<T> evidence$17)
streams
- (undocumented)evidence$17
- (undocumented)
public <T> DStream<T> transform(scala.collection.Seq<DStream<?>> dstreams, scala.Function2<scala.collection.Seq<RDD<?>>,Time,RDD<T>> transformFunc, scala.reflect.ClassTag<T> evidence$18)
dstreams
- (undocumented)transformFunc
- (undocumented)evidence$18
- (undocumented)
public void addStreamingListener(StreamingListener streamingListener)
StreamingListener
object for
receiving system events related to streaming.
streamingListener
- (undocumented)public StreamingContextState getState()
Return the current state of the context. The context can be in three possible states - - StreamingContextState.INTIALIZED - The context has been created, but not been started yet. Input DStreams, transformations and output operations can be created on the context. - StreamingContextState.ACTIVE - The context has been started, and been not stopped. Input DStreams, transformations and output operations cannot be created on the context. - StreamingContextState.STOPPED - The context has been stopped and cannot be used any more.
public void start()
IllegalStateException
- if the StreamingContext is already stopped.public void awaitTermination()
public void awaitTermination(long timeout)
awaitTerminationOrTimeout(Long)
.
timeout
- time to wait in milliseconds
public boolean awaitTerminationOrTimeout(long timeout)
timeout
- time to wait in milliseconds
true
if it's stopped; or throw the reported error during the execution; or false
if the waiting time elapsed before returning from the method.public void stop(boolean stopSparkContext)
stopSparkContext
is not specified, the underlying
SparkContext will also be stopped. This implicit behavior can be configured using the
SparkConf configuration spark.streaming.stopSparkContextByDefault.
stopSparkContext
- If true, stops the associated SparkContext. The underlying SparkContext
will be stopped regardless of whether this StreamingContext has been
started.public void stop(boolean stopSparkContext, boolean stopGracefully)
stopSparkContext
- if true, stops the associated SparkContext. The underlying SparkContext
will be stopped regardless of whether this StreamingContext has been
started.stopGracefully
- if true, stops gracefully by waiting for the processing of all
received data to be completed
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