Azure Core AMQP client library for AMQP operations

Azure Core AMQP is a library that provides common functionality for Azure Javascript libraries that use AMQP protocol like the ones for Azure Service Bus and Azure Event Hubs.

Getting started

Installation

Install this library using npm as follows:

npm install @azure/core-amqp

Note: rhea-promise is a peer dependency. You need to explicitly install this library as a dependency in your application.

Key concepts

Some of the key features of Azure Core AMQP library are:

Claims based Authorization
Request-Response link for sending request and receiving response over AMQP
A Data Transformer class to encode given data to an AMQP message and decode a given AMQP message. Useful for sending and receiving messages that are not of type Buffer.
Error translation of AMQP error codes along with errors specific to Azure Service Bus and Azure Event Hubs.
RetryPolicy for retrying a given operation if a retryable error was encountered.

Claims Based Authorization need to be done for every AMQP link that your application creates. The claims also has to be renewed periodically. For more details on CBS, please see the CBS Specification.

In the below examples, we use the Shared Key details present in the connection string to create a SAS token. This token is then used to make a request on the $cbs link to carry out Claims Based Authorization for a link to the given entity in Azure Service Bus or Azure Event Hubs.

The examples below expect a connection string to a Azure Service Bus or Azure Event Hubs instance. The entity path refers to an Event Hub name in case of Azure Event Hubs and a queue or a topic name in case of Azure Service Bus.

Create a sender link

In the below example, we first create a ConnectionContext which is used to carry out the claims based authorization. Then, we create a sender link using the ConnectionContext.connection to send a message.

async function main() {
  const connectionConfig = ConnectionConfig.create(
    "your-connection-string-with-shared-key",
    "entity-path"
  );
  const connectionContext = ConnectionContextBase.create({
    config: connectionConfig,
    connectionProperties: {
      product: "product",
      userAgent: "/user-agent",
      version: "0.0.0"
    }
  });

  // Carry out the Claims Based Authorization
  await connectionContext.cbsSession.init();
  const token = await connectionContext.tokenCredential.getToken(audience);
  await connectionContext.cbsSession.negotiateClaim(audience, token, TokenType.CbsTokenTypeSas);

  // Create a sender
  const senderName = "your-sender-name";
  const senderOptions = {
    name: senderName,
    target: {
      // For an EventHub Sender bound to a partition, the address will be "<EventHubName>/Partitions/<PartitionId>"
      address: `${connectionConfig.entityPath}`
    },
    onError: (context) => {
      const senderError = context.sender && context.sender.error;
      if (senderError) {
        console.log("An error occurred for sender '%s': %O.", senderName, senderError);
      }
    },
    onSessionError: (context) => {
      const sessionError = context.session && context.session.error;
      if (sessionError) {
        console.log("An error occurred for session of sender '%s': %O.", senderName, sessionError);
      }
    }
  };
  const sender = await connectionContext.connection.createSender(senderOptions);

  // Send a message
  const delivery = await sender.send({ body: "your-message-body" });

  await sender.close();
  await connectionContext.connection.close();
}

main().catch((err) => console.log(err));

Create a receiver link

In the below example, we first create a ConnectionContext which is used to carry out the claims based authorization. Then, we create a receiver link using the ConnectionContext.connection to receive messages for 30 seconds.

async function main() {
  const connectionConfig = ConnectionConfig.create(
    "your-connection-string-with-shared-key",
    "entity-path"
  );
  const connectionContext = ConnectionContextBase.create({
    config: connectionConfig,
    connectionProperties: {
      product: "product",
      userAgent: "/user-agent",
      version: "0.0.0"
    }
  });

  // Carry out the Claims Based Authorization
  await connectionContext.cbsSession.init();
  const token = await connectionContext.tokenCredential.getToken(audience);
  await connectionContext.cbsSession.negotiateClaim(audience, token, TokenType.CbsTokenTypeSas);

  // Create a receiver
  const receiverName = "your-receiver-name";
  const filterClause = `amqp.annotation.x-opt-enqueued-time > '${Date.now() - 3600 * 1000}'`; // Get messages from the past hour
  const receiverAddress = `${connectionConfig.entityPath}/ConsumerGroups/$default/Partitions/0`; // For ServiceBus "<QueueName>"
  const receiverOptions = {
    name: receiverName,
    source: {
      address: receiverAddress,
      filter: {
        // May not be required for ServiceBus. The current example is for EventHubs.
        "apache.org:selector-filter:string": types.wrap_described(filterClause, 0x468c00000004)
      }
    },
    onError: (context) => {
      const receiverError = context.receiver && context.receiver.error;
      if (receiverError) {
        console.log("An error occurred for receiver '%s': %O.", receiverName, receiverError);
      }
    },
    onMessage: (context) => {
      console.log("Received message: %O", context.message);
    },
    onSessionError: (context) => {
      const sessionError = context.session && context.session.error;
      if (sessionError) {
        console.log(
          "An error occurred for session of receiver '%s': %O.",
          receiverName,
          sessionError
        );
      }
    }
  };
  const receiver = await connectionContext.connection.createReceiver(receiverOptions);

  // sleeping for 30 seconds to let the receiver receive messages
  await new Promise((r) => setTimeout(r, 30000));

  // Close the receiver to stop receiving messages
  await receiver.close();
  await connectionContext.connection.close();
}

main().catch((err) => console.log(err));

Troubleshooting

The core-amqp library depends on the rhea-promise library for managing connections, and for sending and receiving events over the AMQP protocol.

Enable logs

You can set the AZURE_LOG_LEVEL environment variable to one of the following values to enable logging to stderr:

verbose
info
warning
error

You can also set the log level programmatically by importing the @azure/logger package and calling the setLogLevel function with one of the log level values. For example, when you set the log level to info, the logs that are written for levels warning and error are also emitted. This SDK follows the Azure SDK for TypeScript guidelines when determining which level to log to.

When setting a log level either programmatically or via the AZURE_LOG_LEVEL environment variable, any logs that are written using a log level equal to or less than the one you choose will be emitted.

You can alternatively set the DEBUG environment variable to get logs when using this library. This can be useful if you also want to emit logs from the dependencies rhea-promise and rhea as well.

Note: AZURE_LOG_LEVEL, if set, takes precedence over DEBUG. Do not specify any azure libraries via DEBUG when also specifying AZURE_LOG_LEVEL or calling setLogLevel.

Getting only info level debug logs from the core-amqp library.

export DEBUG=azure:core-amqp:info

Getting debug logs from the core-amqp and the protocol level library.

export DEBUG=azure:core-amqp:*,rhea*

If you are not interested in viewing the raw event data (which consumes a large amount of console/disk space) then you can set the DEBUG environment variable as follows:

export DEBUG=azure:core-amqp:*,rhea*,-rhea:raw,-rhea:message

If you are interested only in errors and SDK warnings, then you can set the DEBUG environment variable as follows:

export DEBUG=azure:core-amqp:(error|warning),rhea-promise:error,rhea:events,rhea:frames,rhea:io,rhea:flow

Logging to a file

Set the DEBUG environment variable as shown above and then run your test script as follows:
- Logging statements from you test script go to out.log and logging statement from the sdk go to debug.log.
```
node your-test-script.js > out.log 2>debug.log
```
- Logging statements from your test script and the sdk go to the same file out.log by redirecting stderr to stdout (&1), and then redirect stdout to a file:
```
node your-test-script.js >out.log 2>&1
```
- Logging statements from your test script and the sdk go to the same file out.log.
```
node your-test-script.js &> out.log
```

Next steps

Please take a look at the samples directory for detailed samples.

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.microsoft.com.

When you submit a pull request, a CLA-bot will automatically determine whether you need to provide a CLA and decorate the PR appropriately (e.g., label, comment). Simply follow the instructions provided by the bot. You will only need to do this once across all repos using our CLA.

If you'd like to contribute to this library, please read the contributing guide to learn more about how to build and test the code.

This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.

Impressions