azure

Windows Azure SDK for Node.js

This project provides a set of Node.js packages that make it easy to access the Windows Azure storage and queue services. For documentation on how to host Node.js applications on Windows Azure, please see the Windows Azure Node.js Developer Center.

Features

• Tables
  • create and delete tables
  • create, query, insert, update, merge, and delete entities
• Blobs
  • create, list, and delete containers, work with container metadata and permissions, list blobs in container
  • create block and page blobs (from a stream, a file, or a string), work with blob blocks and pages, delete blobs
  • work with blob properties, metadata, leases, snapshot a blob
• Storage Queues
  • create, list, and delete queues, and work with queue metadata
  • create, get, peek, update, delete messages
• Service Bus
  • Queues: create, list and delete queues; create, list, and delete subscriptions; send, receive, unlock and delete messages
  • Topics: create, list, and delete topics; create, list, and delete rules
• Service Runtime
  • get configuration settings and access local resources
  • get role instance information for current role and other role instances
  • query and set the status of the current role

Getting Started

Download Source Code

To get the source code of the SDK via git just type:

git clone https://github.com/WindowsAzure/azure-sdk-for-node.git
cd ./azure-sdk-for-node

Download Package

Alternatively, to get the source code via the Node Package Manager (npm), type

npm install azure

You can use these packages against the cloud Windows Azure Services, or against the local Storage Emulator (with the exception of Service Bus features).

1. To use the cloud services, you need to first create an account with Windows Azure. To use the storage services, you need to set the AZURE_STORAGE_ACCOUNT and the AZURE_STORAGE_ACCESS_KEY environment variables to the storage account name and primary access key you obtain from the Azure Portal. To use Service Bus, you need to set the AZURE_SERVICEBUS_NAMESPACE and the AZURE_SERVICEBUS_ACCESS_KEY environment variables to the service bus namespace and the default key you obtain from the Azure Portal.
2. To use the Storage Emulator, make sure the latest version of the Windows Azure SDK is installed on the machine, and set the EMULATED environment variable to any value ("true", "1", etc.)

Usage

Table Storage

To ensure a table exists, call createTableIfNotExists:

var tableService = azure.createTableService();
tableService.createTableIfNotExists('tasktable', function(error){
    if(!error){
        // Table exists
    }
});

A new entity can be added by calling insertEntity:

var tableService = azure.createTableService(),
    task1 = {
        PartitionKey : 'tasksSeattle',
        RowKey: '1',
        Description: 'Take out the trash',
        DueDate: new Date(2011, 12, 14, 12) 
    };
tableService.insertEntity('tasktable', task1, function(error){ 
    if(!error){
        // Entity inserted
    }
});

The method queryEntity can then be used to fetch the entity that was just inserted:

var tableService = azure.createTableService();
tableService.queryEntity('tasktable', 'tasksSeattle', '1', function(error, serverEntity){
    if(!error){
        // Entity available in serverEntity variable
    }
});

Blob Storage

The createContainerIfNotExists method can be used to create a container in which to store a blob:

var blobService = azure.createBlobService();
blobService.createContainerIfNotExists('taskcontainer', {publicAccessLevel : 'blob'}, function(error){
    if(!error){
        // Container exists and is public
    }
});

To upload a file (assuming it is called task1-upload.txt, it contains the exact text "hello world" (no quotation marks), and it is placed in the same folder as the script below), the method createBlockBlobFromStream can be used:

var blobService = azure.createBlobService();
blobService.createBlockBlobFromStream('taskcontainer', 'task1', fs.createReadStream('task1-upload.txt'), 11, function(error){
    if(!error){
        // Blob uploaded
    }
});

To download the blob and write it to the file system, the getBlobToStream method can be used:

var blobService = azure.createBlobService();
blobService.getBlobToStream('taskcontainer', 'task1', fs.createWriteStream('task1-download.txt'), function(error, serverBlob){
    if(!error){
        // Blob available in serverBlob.blob variable
    }
});

Storage Queues

The createQueueIfNotExists method can be used to ensure a queue exists:

var queueService = azure.createQueueService();
queueService.createQueueIfNotExists('taskqueue', function(error){
    if(!error){
        // Queue exists
    }
});

The createMessage method can then be called to insert the message into the queue:

var queueService = azure.createQueueService();
queueService.createMessage('taskqueue', "Hello world!", function(error){
    if(!error){
        // Message inserted
    }
});

It is then possible to call the getMessage method, process the message and then call deleteMessage inside the callback. This two-step process ensures messages don't get lost when they are removed from the queue.

var queueService = azure.createQueueService(),
    queueName = 'taskqueue';
queueService.getMessages(queueName, function(error, serverMessages){
    if(!error){
        // Process the message in less than 30 seconds, the message
        // text is available in serverMessages[0].messagetext 

        queueService.deleteMessage(queueName, serverMessages[0].messageid, serverMessages[0].popreceipt, function(error){
            if(!error){
                // Message deleted
            }
        });
    }
});

Service Bus Queues

Service Bus Queues are an alternative to Storage Queues that might be useful in scenarios where more advanced messaging features are needed (larger message sizes, message ordering, single-operaiton destructive reads, scheduled delivery) using push-style delivery (using long polling).

The createQueueIfNotExists method can be used to ensure a queue exists:

var serviceBusService = azure.createServiceBusService();
serviceBusService.createQueueIfNotExists('taskqueue', function(error){
    if(!error){
        // Queue exists
    }
});

The sendQueueMessage method can then be called to insert the message into the queue:

var serviceBusService = azure.createServiceBusService();
serviceBusService.sendQueueMessage('taskqueue', 'Hello world!', function(
    if(!error){
        // Message sent
     }
});

It is then possible to call the receiveQueueMessage method to dequeue the message.

var serviceBusService = azure.createServiceBusService();
serviceBusService.receiveQueueMessage('taskqueue', function(error, serverMessage){
    if(!error){
        // Process the message
    }
});

Service Bus Topics

Service Bus topics are an abstraction on top of Service Bus Queues that make pub/sub scenarios easy to implement.

The createTopicIfNotExists method can be used to create a server-side topic:

var serviceBusService = azure.createServiceBusService();
serviceBusService.createTopicIfNotExists('taskdiscussion', function(error){
    if(!error){
        // Topic exists
    }
});

The sendTopicMessage method can be used to send a message to a topic:

var serviceBusService = azure.createServiceBusService();
serviceBusService.sendTopicMessage('taskdiscussion', 'Hello world!', function(error){
    if(!error){
        // Message sent
    }
});

A client can then create a subscription and start consuming messages by calling the createSubscription method followed by the receiveSubscriptionMessage method. Please note that any messages sent before the subscription is created will not be received.

var serviceBusService = azure.createServiceBusService(),
    topic = 'taskdiscussion',
    subscription = 'client1';

serviceBusService.createSubscription(topic, subscription, function(error1){
    if(!error1){
        // Subscription created

        serviceBusService.receiveSubscriptionMessage(topic, subscription, function(error2, serverMessage){
            if(!error2){
                // Process message
            }
        });
     }
});

Service Runtime

The Service Runtime allows you to interact with the machine environment where the current role is running. Please note that these commands will only work if your code is running inside the Azure emulator or in the cloud.

The getConfigurationSettings method lets you obtain values from the role's .cscfg file.

azure.RoleEnvironment.getConfigurationSettings(function(error, settings) {
    if (!error) {
        // You can get the value of setting "setting1" via settings['setting1']
    }        
});

The getLocalResources method lets you obtain data from the role's local storage.

azure.RoleEnvironment.getLocalResources(function(error, resources) {
    if(!error){
        // You can get the path to the role's diagnostics store via 
        // resources['DiagnosticStore']['path']
    }
});

The getCurrentRoleInstance method lets you obtain information about where the current instance is running, among other things:

azure.RoleEnvironment.getCurrentRoleInstance(function(error, instance) {
    if (!error && instance['endpoints']) {
        // You can get information about "endpoint1" such as its address and port via
        // instance['endpoints']['endpoint1']['address'] and instance['endpoints']['endpoint1']['port']
    }
});

The getRoles method lets you obtain information about role instances running on other machines:

azure.RoleEnvironment.getRoles(function(error, roles) {
    if(!error){
        // You can get information about "instance1" of "role1" via roles['role1']['instance1']
    } 
});

For more examples please see the Windows Azure Node.js Developer Center

Need Help?

Be sure to check out the Windows Azure Developer Forums on Stack Overflow if you have trouble with the provided code.

Contribute Code or Provide Feedback

If you would like to become an active contributor to this project please follow the instructions provided in Windows Azure Projects Contribution Guidelines.

If you encounter any bugs with the library please file an issue in the Issues section of the project.

Learn More

Windows Azure Node.js Developer Center

Changelog

2012.04.19 Version 0.5.3

• Service Runtime Wrappers
• Multiple Bugfixes
• Unit tests converted to mocha and code coverage made easy through JSCoverage