Java SDK v4 Sample Code #2

anfeldma-ms · 2020-03-10T00:51:11Z

No description provided.

moderakh · 2020-03-10T15:04:03Z

README.md

+To choose which sample will run, populate the **Main class** field of the Configuration with 
+
+```
+com.azure.cosmos.examples.changefeed.sample


This is changefeed package. If we are including changefeed samples here as well, please move them bellow other crud samples, as the most basic samples are crud.

moderakh · 2020-03-10T15:04:33Z

README.md

+*Build and execute from command line without an IDE:* From top-level directory of repo:
+```
+mvn clean package
+mvn exec:java -Dexec.mainClass="com.azure.cosmos.examples.changefeed.sample" -DACCOUNT_HOST=your account hostname -DACCOUNT_KEY=your account master key


ditto, the sample has changefeed in the package name
com.azure.cosmos.examples.changefeed.sample

pom.xml

src/main/java/com/azure/cosmos/examples/common/CustomPOJO.java

src/main/java/com/azure/cosmos/examples/crudquickstart/async/SampleCRUDQuickstartAsync.java

moderakh · 2020-03-10T15:10:32Z

src/main/java/com/azure/cosmos/examples/crudquickstart/async/SampleCRUDQuickstartAsync.java

+                        err.printStackTrace();
+                    }
+
+                    completionLatch.countDown();


We should remove countdown latch for sample if possible, they are hard to understand.

moderakh · 2020-03-10T15:11:12Z

src/main/java/com/azure/cosmos/examples/crudquickstart/async/SampleCRUDQuickstartAsync.java

+                                    err.printStackTrace();
+                                }
+
+                                completionLatch.countDown();


we should try to remove countdown latch for samples, they are hard to understand.

moderakh · 2020-03-10T15:11:22Z

src/main/java/com/azure/cosmos/examples/crudquickstart/async/SampleCRUDQuickstartAsync.java

+
+                completionLatch.countDown();
+            },
+            () -> {completionLatch.countDown();}


moderakh

I have seen customers just copy paste samples to their own prod code

we should consider moving away from countdown latch, they are hard to understand in basic entry samples.
for async operation we should try to do more chaining when possible
we should consider using slf4j/log4j2 for logging (instead of system.out) and point the logger to std out, also we should make a comment in the log4j2 config that for real use async log4j2 config should be used.
the samples should reference CRUD before referencing changefeed.

…a.1 jar; updated samples for new jar

…ually and also other improvements were made.

README.md

src/main/java/com/azure/cosmos/examples/changefeed/SampleChangeFeedProcessor.java

…rove explanatory comments in all samples

milismsft · 2020-03-10T21:01:45Z

src/main/java/com/azure/cosmos/examples/changefeed/SampleChangeFeedProcessor.java

+            //This sample models an application where documents are being inserted into one container (the "feed container"),
+            //and meanwhile another worker thread or worker application is pulling inserted documents from the feed container's Change Feed
+            //and operating on them in some way. For one or more workers to process the Change Feed of a container, the workers must first contact the server
+            //and "lease" access to monitor one or more partitions of the feed container. The Change Feed Processor Library


We should try to simplify this comment and add the following:

"A secondary Cosmos container ("lease container") is required in order to keep track of the documents being processed and resume the work from where it was left in case the processing is stopped. When the "feed container" has multiple partitions, corresponding number of "lease documents" are created and the Change Feed Processor instance will create equal amount of individual workers that will automatically process each partition in a multithread manner. In such cases the user's provided handler implementation can be invoked from different threads and execute in parallel. Multiple instances of the Change Feed Processor (i.e. running on different virtual machines) can operate on the same "feed container" at the same time to further parallelize the workload. Change Feed Processor library implement a load balancing component that will ensure more or less equal distribution of the workload among different instances."

milismsft · 2020-03-10T21:04:00Z

src/main/java/com/azure/cosmos/examples/changefeed/SampleChangeFeedProcessor.java

+            //Processor Library can store and track leases container partitions.
+
+            //Summary of the next four commands:
+            //-Create an asynchronous Azure Cosmos DB client and database so that we can issue async requests to the DB


We need to add a disclaimer here that by creating the Cosmos containers and executing work on them, there will be charges associated with. We should also capture the default RU we set and link to the charges doc/web page.

milismsft · 2020-03-10T21:05:29Z

src/main/java/com/azure/cosmos/examples/changefeed/SampleChangeFeedProcessor.java

+        logger.info("END Sample");
+    }
+
+    public static ChangeFeedProcessor getChangeFeedProcessor(String hostName, CosmosAsyncContainer feedContainer, CosmosAsyncContainer leaseContainer) {


For each individual method it will be great if we can capture a short summary of what it is doing.

milismsft · 2020-03-10T21:08:12Z

src/main/java/com/azure/cosmos/examples/changefeed/SampleConfigurations.java

+ */
+public final class SampleConfigurations {
+    // REPLACE MASTER_KEY and HOST with values from your Azure Cosmos DB account.
+    // The default values are credentials of the local emulator, which are not used in any production environment.


local emulator -> Cosmos Public Emulator which can be downloaded from https://aka.ms/cosmosdb-emulator

milismsft · 2020-03-10T21:11:48Z

src/main/java/com/azure/cosmos/examples/changefeed/SampleConfigurations.java

+// Licensed under the MIT License.
+package com.azure.cosmos.examples.changefeed;
+
+import com.google.common.base.Strings;


Can we avoid taking any other dependencies and just the ones in Java (or Cosmos SDK)? As Mo commented, people tend to copy/paste the sample code in their apps and we should try to avoid bringing new dependencies that are not required for their app to execute.

milismsft · 2020-03-10T21:19:04Z

src/main/java/com/azure/cosmos/examples/changefeed/SampleChangeFeedProcessor.java

+
+            //These two lines model an application which is inserting ten documents into the feed container
+            logger.info("-->START application that inserts documents into feed container");
+            createNewDocumentsCustomPOJO(feedContainer, 10, Duration.ofSeconds(3));


Instead of using a bare bone CustomPOJO, it might be worth using one of the other POJO classes such a Family for instance. It will help make it more clear how properties will map and be accessed.

milismsft · 2020-03-10T21:23:40Z

src/main/java/com/azure/cosmos/examples/storedprocedure/async/SampleStoredProcedureAsync.java

+        executeStoredProcedure();
+
+        //Perform a point-read to confirm that the item with id test_doc exists
+        logger.info("Checking that a document was created by the stored procedure...");


The document check should be done inside executeStoredProcedure().

anfeldma-ms added 2 commits March 9, 2020 17:47

Added .gitignore

f763fec

Java SDK v4 sample code

e5a4af4

anfeldma-ms requested review from kushagraThapar, milismsft, moderakh, simplynaveen20 and David-Noble-at-work March 10, 2020 00:51

Updated pom.xml to latest release

c3f0847

moderakh suggested changes Mar 10, 2020

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moderakh self-requested a review March 10, 2020 15:17

moderakh suggested changes Mar 10, 2020

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anfeldma-ms and others added 5 commits March 10, 2020 10:17

Fixed pom.xml and modified CRUD quickstart

5eb8c47

Manually merged fixes from master: pom.xml fix given latest 4.0.1-bet…

7db028a

…a.1 jar; updated samples for new jar

Fixed logging

4b1d76b

Slight modification to log4j2 properties; fixed import formatting

07ebbf4

Pulling in master, in which the previous two commits were applied man…

c846111

…ually and also other improvements were made.

milismsft reviewed Mar 10, 2020

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milismsft reviewed Mar 10, 2020

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anfeldma-ms added 2 commits March 10, 2020 13:54

Manual merge of changes from master: make README.md IDE-agnostic; imp…

18f564b

…rove explanatory comments in all samples

Cleaned up the code

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milismsft reviewed Mar 10, 2020

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Java SDK v4 Sample Code #2

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