App

Overview

The Files component is an abstraction of persistent queues with a default implementation using AWS SQS. This also provides a much simplified API while making the underlying implementation swappable.

Status

This component is currently stable. Following limitations, current work, planned features apply.

Feature	Status	Description
Meta	Upcoming	Ability to easily default / inject meta data for every entry.
URI	Upcoming	Ability to use Slate Kit Uri for explicit references to file paths
Errors	Upcoming	Ability to use a dead-letter queue for failed items.
Batch	Upcoming	Ability to perform batch insert operations

Install

    repositories {
        // other repositories
        maven { url  "http://dl.bintray.com/codehelixinc/slatekit" }
    }

    dependencies {
        // other dependencies ...

        compile 'com.slatekit:slatekit-cloud:1.0.0'
    }

Sources

Jar	slatekit.cloud.jar
Package	slatekit.cloud
Sources	slatekit-cloud
Example	Example_Cloud_Queues.kt
Requires	See build.gradle for more info.

Imports

Refer to Example_Cloud_Queues.kt for all imports.

         
    // Required
    import slatekit.cloud.aws.SQS
    import slatekit.core.queues.QueueEntry
    import slatekit.core.queues.QueueStringConverter

    // Optional ( For examples)
    import com.amazonaws.auth.profile.ProfileCredentialsProvider
    import com.amazonaws.regions.Regions

Setup

        
    // This converts the queue entry payload to a type
    // NOTES:
    // 1. This can be String converter for any payload ( e.g. JSON )
    // 2. You can create a custom type for type safety
    val converter = QueueStringConverter()
    
    // Not storing any key/secret in source code for security purposes
    // Setup 1: Use the default aws config file in "~/.aws/credentials and supply AWS region
    val queue1 = SQS<String>(credentials = ProfileCredentialsProvider().credentials,
            region = Regions.US_EAST_1, name = "slatekit", converter = converter)

    // Setup 2: Allow auto-loading of credentials from ~/.aws/credentials and region by string name supplied
    val queue2 = SQS.of<String>(region = "us-east-1", name = "slatekit", converter = converter)

    // Setup 3: Use the config at "~/myapp/conf/queue.conf"
    // Reads from the section "queues" by default
    /**
     *  SAMPLE CONFIG:
     *  queues = true
     *  queues.key  = AWS_KEY_HERE
     *  queues.pass = AWS_PASSWORD_HERE
     *  queues.env  = dev
     *  queues.tag  = samples
     */
    val queue3 = SQS.of<String>( region = "us-east-1", name = "slatekit", converter = converter,
        confPath = "~/myapp/conf/queue.conf", confSection = "queues")

    val queue = queue3.getOrElse { queue1 }

Usage

        
    // Use case 1: init()
    queue.init()

    // NOTES:
    // 1. All operations use the slate kit Result<T,E> type
    // 2. All operations return a slate kit Try<T> = Result<T, Exception>
    // Use case 2: send 1 message ( get back message id as String )
    queue.send("item 1")

    // Use case 3: send multiple messages
    queue.send("item 2")

    // Use case 4: send message with tags
    queue.send("user=kishore", tagName = "type", tagValue = "reg")

    // Use case 5: receive 1 message
    val item1 = queue.next()
    println(item1?.getValue())
    println(item1?.getTag("type"))

    // Use case 6: recieve 2 messages
    val items = queue.next(2)

    // Use case 7: delete a message
    queue.done(item1)

    // Use case 8: delete many
    queue.done(items)

    // Use case 9: abandon a message
    queue.abandon(queue.next())

    // Use case 10: get count ( approximation )
    val count = queue.count()
    println(count)