Application Services - Getting Started
Types of Application Services
There are two flavors of Applications Service which are configurable
and custom
. This section will describe how and when each flavor should be used.
Configurable
The App Functions SDK
has a full suite of built-in pipeline functions that are accessible via configuration when using the App Service Configurable
service. This service is built using the App Functions SDK
and uses configuration profiles to define separate distinct instances of the service. The service comes with a few built in profiles for common use cases, but custom profiles can also be used. If your use case needs can be met with the built-in functionality then the App Service Configurable
service is right for you. See the App Service Configurable section for more details.
Custom
Custom Application Services are needed when use case needs can not be met with just the built-in functionality. This is when you must develop you own custom Application Service using the App Functions SDK. Typically, this is triggered by the use case needing a custom pipeline function to process the data in a way not provided by the App Functions SDK. See the App Functions SDK section for all the details on the features your custom Application Service can take advantage of.
Template
To help accelerate the creation of your new custom Application Service the App Functions SDK contains a template for new custom Application Services. This template has TODOs in the code and a README that walk you through the creation of your new custom Application Service. See the template README for more details.
Triggers
Triggers
are common to both Configurable
and Custom
Application Services. They are the next logical area to get familiar with. See the Triggers section for more details.
Configuration
Service configuration is very important to understand for both Configurable and Custom Application Services. The application service configuration documentation is broken into three parts. First is the configuration that is common to all EdgeX services, second is the configuration that is common to all Application Services and third is the configuration for App Service Configurable. See the following sections for more details on each:
- EdgeX Common Configuration
- Application Service Common Configuration
- App Service Configurable Configuration
Examples
There are many example custom application services that are a great place to start getting familiar with Application Services. See Application Service Examples for the complete list a links. They include an example profile for App Service Configurable.