public final class DynamoDBIO
extends java.lang.Object
Example usage:
PCollection<List<Map<String, AttributeValue>>> output =
pipeline.apply(
DynamoDBIO.<List<Map<String, AttributeValue>>>read()
.withScanRequestFn(in -> ScanRequest.builder().tableName(tableName).totalSegments(1).build())
.items()); // ScanResponse items mapper
At a minimum you have to provide:
scanRequestFn providing the ScanRequest instance; table name and
total segments are required. Note: Choose total segments according to the
number of workers used.
scanResponseMapperFn to map the ScanResponse to the expected output type,
such as DynamoDBIO.Read.items().
Example usage:
PCollection<T> data = ...;
SerializableFunction<T, WriteRequest> requestBuilder = ...;
data.apply(
DynamoDBIO.<WriteRequest>write()
.withWriteRequestMapperFn(t -> KV.of(tableName, requestBuilder.apply(t))));
At a minimum you have to provide a writeRequestMapperFn to map each element into a
KV of table name and WriteRequest.
Note: AWS does not allow writing duplicate keys within a single batch operation. If
primary keys possibly repeat in your stream (i.e. an upsert stream), you may encounter a
`ValidationError`. To address this you have to provide the key names corresponding to your
primary key using DynamoDBIO.Write.withDeduplicateKeys(List). Based on these keys only the last
observed element is kept. Nevertheless, if no deduplication keys are provided, identical elements
are still deduplicated.
AWS clients for all AWS IOs can be configured using AwsOptions, e.g. --awsRegion=us-west-1. AwsOptions contain reasonable defaults based on default providers
for Region and AwsCredentialsProvider.
If you require more advanced configuration, you may change the ClientBuilderFactory
using AwsOptions.setClientBuilderFactory(Class).
Configuration for a specific IO can be overwritten using withClientConfiguration(),
which also allows to configure the retry behavior for the respective IO.
Retries for failed requests can be configured using ClientConfiguration.Builder#retry(Consumer) and are handled by the AWS SDK unless there's a
partial success (batch requests). The SDK uses a backoff strategy with equal jitter for computing
the delay before the next retry.
Note: Once retries are exhausted the error is surfaced to the runner which may then opt to retry the current partition in entirety or abort if the max number of retries of the runner is reached.
| Modifier and Type | Class and Description |
|---|---|
static class |
DynamoDBIO.Read<T>
Read data from DynamoDB using
DynamoDBIO.Read.getScanRequestFn() and emit an element of type T
for each ScanResponse using the mapping function DynamoDBIO.Read.getScanResponseMapperFn(). |
static class |
DynamoDBIO.Write<T>
Write a PCollection
|
| Constructor and Description |
|---|
DynamoDBIO() |
| Modifier and Type | Method and Description |
|---|---|
static <T> DynamoDBIO.Read<T> |
read() |
static <T> DynamoDBIO.Write<T> |
write() |
public static <T> DynamoDBIO.Read<T> read()
public static <T> DynamoDBIO.Write<T> write()