Subsonic Alexa Skill

This is a custom Alexa skill that allows you to play music from a Subsonic server. This skill also works with every server that implements the Subsonic API like Airsonic or Libresonic.

Usage

This skill has not been published which means you need to deploy it yourself to your personal amazon account. You can do that by following the steps described in the Setup section.

After you setup the skill it will be available on all of your Alexa devices that are connected to the same account you used to deploy your skill. You can now start the skill like any other skill by using its invocation name. See Alexa documentation for more details on how to invoke a skill.

Currently, this skill only supports the playback of playlists. You cannot play specific songs or search for songs.

When you have invoked the skill you can play a playlist by saying something along the lines of play playlist <playlist name>, depending on the locale you chose during the setup. You can also skip a song the same way you would skip a song in any other audio skill.

Setup

Create the Skill

First you need to create a new Alexa skill in the Alexa Developer console. This general process of creating a skill is described in the Alexa documentation.

Use the JSON editor for the skill model and paste in the content of one of the files in the model directory depending on your locale. If you want another language or want to use different phrases for the skill's action feel free to edit the model.

After you have saved the model you have to build it using the Build Model button.

Add Skill Interfaces

Since this skill plays audio on your Alexa device it needs the Audio Player interface to be enabled. Make sure that it's enabled, otherwise the skill won't work.

Add Skill Endpoint

As Endpoint add an AWS Lambda ARN endpoint. Copy the ARN that you get in the Deploy the Lambda function step and paste in in the Default Region field. This will connect the Lambda function to your skill.

Deploy the Lambda function

Alexa skills use AWS Lambda functions as backend. See AWS Lambda documentation for more details.

If you don't have an AWS account yet, create one. Deploying a lambda function can be done as part of the AWS Free Tier so it doesn't cost you any money.

Deploy a new lambda function and upload this application as .zip or .jar file. You can create the necessary jar file by running the following maven command (requires maven to be installed on your machine):

mvn org.apache.maven.plugins:maven-assembly-plugin:2.6:assembly -DdescriptorId=jar-with-dependencies package

You can either upload it in the AWS Console or, if you have aws cli installed, use the build.sh script to build it and upload it to your function in one step. If you do it with the build script replace alexa-skill-subsonic with the name of your lambda function first.

Deploy DynamoDB Table

This skill requires a DynamoDB table to store the playback state and other configuration. Create a new DynamoDB table and after that create a new Policy with the following configuration:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "1",
            "Effect": "Allow",
            "Action": [
                "dynamodb:PutItem",
                "dynamodb:GetItem",
                "dynamodb:UpdateItem"
            ],
            "Resource": "arn:aws:dynamodb:*:*:table/subsonic-alexa-skill"
        }
    ]
}

This Policy defined read and write access to your DynamoDB table. Replace subsonic-alexa-skill with the name of your table.

After you created the policy, attach it to the execution role of your lambda function. You can find your execution role under Configuration -> Permissions -> Execution role in the lambda function view. This finally gives your lambda function access to your DynamoDB table.

Configuration

This skill needs some configuration passed as environment variables. Go to Configuration -> Environment variables -> Edit and configure the following variables:

Key	Value
DYNAMODB_TABLE	The name of your DynamoDB table
LOCALE	The locale that should be used for the response phrases (e.g. en-US). This value will be mapped to a file in the phrases directory. If you want to add another locale or change the response phrases you can add a file there or edit one of the exisitng file. Remember to re-build and upload the application again after changing those files.
SUBSONIC_URL	The public URL of your subsonic server
SUBSONIC_USERNAME	The name of the user for your subsonic server
SUBSONIC_PASSWORD	The password of the user for your subsonic server

After you apply the configuration the lambda function will automatically be updated.

The skill should now work. See Usage section for details on how to use the skill.