org.apache.beam.sdk.io.mongodb

Class MongoDbGridFSIO

java.lang.Object

org.apache.beam.sdk.io.mongodb.MongoDbGridFSIO

public class MongoDbGridFSIO
extends java.lang.Object

IO to read and write data on MongoDB GridFS.

Reading from MongoDB via GridFS

MongoDbGridFSIO source returns a bounded collection of Objects as PCollection<T>.

To configure the MongoDB GridFS source, you can provide the connection URI, the database name and the bucket name. If unspecified, the default values from the GridFS driver are used.

The following example illustrates various options for configuring the source:

 pipeline.apply(MongoDbGridFSIO.<String>read()
   .withUri("mongodb://localhost:27017")
   .withDatabase("my-database")
   .withBucket("my-bucket"))
 

The source also accepts an optional configuration: withQueryFilter() allows you to define a JSON filter to get subset of files in the database.

There is also an optional Parser (and associated Coder) that can be specified that can be used to parse the InputStream into objects usable with Beam. By default, MongoDbGridFSIO will parse into Strings, splitting on line breaks and using the uploadDate of the file as the timestamp. When using a parser that outputs with custom timestamps, you may also need to specify the allowedTimestampSkew option.

Writing to MongoDB via GridFS

MongoDBGridFS supports writing of data to a file in a MongoDB GridFS collection.

To configure a MongoDB GridFS sink, you can provide the connection URI, the database name and the bucket name. You must also provide the filename to write to. Another optional parameter is the GridFS file chunkSize.

For instance:

 pipeline
   .apply(...)
   .apply(MongoDbGridFSIO.write()
     .withUri("mongodb://localhost:27017")
     .withDatabase("my-database")
     .withBucket("my-bucket")
     .withChunkSize(256000L)
     .withFilename("my-output.txt"))

 

There is also an optional argument to the create() method to specify a writer that is used to write the data to the OutputStream. By default, it writes UTF-8 strings to the file separated with line feeds.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	MongoDbGridFSIO.ConnectionConfiguration Encapsulate the MongoDB GridFS connection logic.
static interface	MongoDbGridFSIO.Parser<T> Interface for the parser that is used to parse the GridFSDBFile into the appropriate types.
static interface	MongoDbGridFSIO.ParserCallback<T> Callback for the parser to use to submit data.
static class	MongoDbGridFSIO.Read<T> A PTransform to read data from MongoDB GridFS.
static class	MongoDbGridFSIO.Write<T> A PTransform to write data to MongoDB GridFS.
static interface	MongoDbGridFSIO.WriteFn<T> Function that is called to write the data to the give GridFS OutputStream.

Constructor Summary

Constructors

Constructor and Description
MongoDbGridFSIO()

Method Summary

Modifier and Type	Method and Description
static MongoDbGridFSIO.Read<java.lang.String>	read() Read data from GridFS.
static MongoDbGridFSIO.Write<java.lang.String>	write() Write data to GridFS.
static <T> MongoDbGridFSIO.Write<T>	write(MongoDbGridFSIO.WriteFn<T> fn)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MongoDbGridFSIO

public MongoDbGridFSIO()

Method Detail

read

public static MongoDbGridFSIO.Read<java.lang.String> read()

Read data from GridFS. Default behavior with String.

write

public static MongoDbGridFSIO.Write<java.lang.String> write()

Write data to GridFS. Default behavior with String.

write

public static <T> MongoDbGridFSIO.Write<T> write(MongoDbGridFSIO.WriteFn<T> fn)