| --- |
| title: API - Write Records (via write proxy) |
| top-nav-group: quickstart |
| top-nav-pos: 3 |
| top-nav-title: API - Write Records (via write proxy) |
| layout: default |
| --- |
| |
| .. contents:: Basic Tutorial - Using Proxy Client to write records |
| |
| Basic Tutorial - Write Records using Write Proxy Client |
| ======================================================= |
| |
| This tutorial shows how to write records using write proxy client. |
| |
| .. sectnum:: |
| |
| Open a write proxy client |
| ~~~~~~~~~~~~~~~~~~~~~~~~~ |
| |
| Create write proxy client builder |
| --------------------------------- |
| |
| :: |
| |
| DistributedLogClientBuilder builder = DistributedLogClientBuilder.newBuilder(); |
| .clientId(ClientId.apply("console-proxy-writer")) |
| .name("console-proxy-writer"); |
| |
| |
| Enable thrift mux |
| ----------------- |
| |
| :: |
| |
| builder = builder.thriftmux(true); |
| |
| |
| Point the client to write proxy using finagle name |
| -------------------------------------------------- |
| |
| :: |
| |
| String finagleNameStr = "inet!127.0.0.1:8000"; |
| builder = builder.finagleNameStr(finagleNameStr); |
| |
| |
| Build the write proxy client |
| ---------------------------- |
| |
| :: |
| |
| DistributedLogClient client = builder.build(); |
| |
| |
| Write Records |
| ~~~~~~~~~~~~~ |
| |
| Write records to a stream |
| ------------------------- |
| |
| Application does not have to provide `TransactionID` on writing. |
| The `TransactionID` of a record is assigned by the write proxy. |
| |
| :: |
| |
| String streamName = "basic-stream-2"; |
| byte[] data = ...; |
| Future<DLSN> writeFuture = client.write(streamName, ByteBuffer.wrap(data)); |
| |
| |
| Register the write callback |
| --------------------------- |
| |
| Register a future listener on write completion. The writer will be notified once the write is completed. |
| |
| :: |
| |
| writeFuture.addEventListener(new FutureEventListener<DLSN>() { |
| @Override |
| public void onFailure(Throwable cause) { |
| // executed when write failed. |
| } |
| |
| @Override |
| public void onSuccess(DLSN value) { |
| // executed when write completed. |
| } |
| }); |
| |
| |
| Close the write proxy client |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| |
| Close the write proxy client after usage. |
| |
| :: |
| |
| client.close(); |
| |
| |
| Run the tutorial |
| ~~~~~~~~~~~~~~~~ |
| |
| Run the example in the following steps: |
| |
| Start the local bookkeeper cluster |
| ---------------------------------- |
| |
| You can use follow command to start the distributedlog stack locally. |
| After the distributedlog cluster is started, you could access it using |
| distributedlog uri *distributedlog://127.0.0.1:7000/messaging/distributedlog*. |
| |
| :: |
| |
| // dlog local ${zk-port} |
| ./distributedlog-core/bin/dlog local 7000 |
| |
| |
| Start the write proxy |
| --------------------- |
| |
| Start the write proxy, listening on port 8000. |
| |
| :: |
| |
| // DistributedLogServerApp -p ${service-port} --shard-id ${shard-id} -sp ${stats-port} -u {distributedlog-uri} -mx -c ${conf-file} |
| ./distributedlog-service/bin/dlog org.apache.distributedlog.service.DistributedLogServerApp -p 8000 --shard-id 1 -sp 8001 -u distributedlog://127.0.0.1:7000/messaging/distributedlog -mx -c ${distributedlog-repo}/distributedlog-service/conf/distributedlog_proxy.conf |
| |
| |
| Create the stream |
| ----------------- |
| |
| Create the stream under the distributedlog uri. |
| |
| :: |
| |
| // Create Stream `basic-stream-2` |
| // dlog tool create -u ${distributedlog-uri} -r ${stream-prefix} -e ${stream-regex} |
| ./distributedlog-core/bin/dlog tool create -u distributedlog://127.0.0.1:7000/messaging/distributedlog -r basic-stream- -e 2 |
| |
| |
| Tail the stream |
| --------------- |
| |
| Tailing the stream using `TailReader` to wait for new records. |
| |
| :: |
| |
| // Tailing Stream `basic-stream-2` |
| // runner run org.apache.distributedlog.basic.TailReader ${distributedlog-uri} ${stream} |
| ./distributedlog-tutorials/distributedlog-basic/bin/runner run org.apache.distributedlog.basic.TailReader distributedlog://127.0.0.1:7000/messaging/distributedlog basic-stream-2 |
| |
| |
| Write records |
| ------------- |
| |
| Run the example to write records to the stream in a console. |
| |
| :: |
| |
| // Write Records into Stream `basic-stream-2` |
| // runner run org.apache.distributedlog.basic.ConsoleProxyWriter ${distributedlog-uri} ${stream} |
| ./distributedlog-tutorials/distributedlog-basic/bin/runner run org.apache.distributedlog.basic.ConsoleProxyWriter 'inet!127.0.0.1:8000' basic-stream-2 |
| |
| |
| Check the results |
| ----------------- |
| |
| Example output from `ConsoleProxyWriter` and `TailReader`. |
| |
| :: |
| |
| // Output of `ConsoleProxyWriter` |
| May 08, 2016 10:27:41 AM com.twitter.finagle.BaseResolver$$anonfun$resolvers$1 apply |
| INFO: Resolver[inet] = com.twitter.finagle.InetResolver(com.twitter.finagle.InetResolver@756d7bba) |
| May 08, 2016 10:27:41 AM com.twitter.finagle.BaseResolver$$anonfun$resolvers$1 apply |
| INFO: Resolver[fixedinet] = com.twitter.finagle.FixedInetResolver(com.twitter.finagle.FixedInetResolver@1d2e91f5) |
| May 08, 2016 10:27:41 AM com.twitter.finagle.BaseResolver$$anonfun$resolvers$1 apply |
| INFO: Resolver[neg] = com.twitter.finagle.NegResolver$(com.twitter.finagle.NegResolver$@5c707aca) |
| May 08, 2016 10:27:41 AM com.twitter.finagle.BaseResolver$$anonfun$resolvers$1 apply |
| INFO: Resolver[nil] = com.twitter.finagle.NilResolver$(com.twitter.finagle.NilResolver$@5c8d932f) |
| May 08, 2016 10:27:41 AM com.twitter.finagle.BaseResolver$$anonfun$resolvers$1 apply |
| INFO: Resolver[fail] = com.twitter.finagle.FailResolver$(com.twitter.finagle.FailResolver$@52ba2221) |
| May 08, 2016 10:27:41 AM com.twitter.finagle.Init$$anonfun$1 apply$mcV$sp |
| [dlog] > test-proxy-writer |
| [dlog] > |
| |
| |
| // Output of `TailReader` |
| Opening log stream basic-stream-2 |
| Log stream basic-stream-2 is empty. |
| Wait for records starting from DLSN{logSegmentSequenceNo=1, entryId=0, slotId=0} |
| Received record DLSN{logSegmentSequenceNo=1, entryId=0, slotId=0} |
| """ |
| test-proxy-writer |
| """ |
| |
| |
| Attempt a second writer |
| ----------------------- |
| |
| Open another terminal to run `ConsoleProxyWriter`. The write should succeed as write proxy is able to accept |
| fan-in writes. Please checkout section `Considerations` to see the difference between **Write Ordering** and |
| **Read Ordering**. |
| |
| :: |
| |
| May 08, 2016 10:31:54 AM com.twitter.finagle.BaseResolver$$anonfun$resolvers$1 apply |
| INFO: Resolver[inet] = com.twitter.finagle.InetResolver(com.twitter.finagle.InetResolver@756d7bba) |
| May 08, 2016 10:31:54 AM com.twitter.finagle.BaseResolver$$anonfun$resolvers$1 apply |
| INFO: Resolver[fixedinet] = com.twitter.finagle.FixedInetResolver(com.twitter.finagle.FixedInetResolver@1d2e91f5) |
| May 08, 2016 10:31:54 AM com.twitter.finagle.BaseResolver$$anonfun$resolvers$1 apply |
| INFO: Resolver[neg] = com.twitter.finagle.NegResolver$(com.twitter.finagle.NegResolver$@5c707aca) |
| May 08, 2016 10:31:54 AM com.twitter.finagle.BaseResolver$$anonfun$resolvers$1 apply |
| INFO: Resolver[nil] = com.twitter.finagle.NilResolver$(com.twitter.finagle.NilResolver$@5c8d932f) |
| May 08, 2016 10:31:54 AM com.twitter.finagle.BaseResolver$$anonfun$resolvers$1 apply |
| INFO: Resolver[fail] = com.twitter.finagle.FailResolver$(com.twitter.finagle.FailResolver$@52ba2221) |
| May 08, 2016 10:31:54 AM com.twitter.finagle.Init$$anonfun$1 apply$mcV$sp |
| [dlog] > test-write-proxy-message-2 |
| [dlog] > |