Composing actions

Let's go through an example of a manifest for a composite action. This action gets uses the OpenWeather api to fetch the weather by a location name. However, since the open weather api does not offer the functionality to fetch the weather by location name directly, we need break the flow into two steps:

1. Get the latitude and longitude by location name

2. Get the weather by latitude and longitude

{
  "name": "get-weather-by-location-name",
  "description": "Get weather by location name",
  "version": "0.0.1",
  "kind": "composition",
  "manifest_version": 1,
  "repository": "github.com/tgirotto/get-weather-by-location-name",
  "license": "MIT",
  "inputs": [
    {
      "name": "weather_config",
      "type": "WeatherConfig",
      "required": true
    }
  ],
  "steps": {
    "get_coordinates": {
      "uses": "tgirotto/openweather-coordinates-by-location-name:0.0.1",
      "inputs": [
        {
          "location_name": "{{inputs[0].location_name}}",
          "open_weather_api_key": "{{inputs[0].open_weather_api_key}}"
        }
      ]
    },
    "get_weather": {
      "uses": "tgirotto/openweather-current-weather:0.0.1",
      "inputs": [
        {
          "lat": "{{steps.get_coordinates.outputs[0].lat}}",
          "lon": "{{steps.get_coordinates.outputs[0].lon}}",
          "open_weather_api_key": "{{inputs[0].open_weather_api_key}}"
        }
      ]
    }
  },
  "outputs": [
    {
      "name": "response",
      "description": "Simplified weather information for the location",
      "type": "CustomWeatherResponse",
      "value": {
        "location_name": "{{inputs[0].location_name}}",
        "weather": "{{steps.get_weather.outputs[0].weather[0].description}}"
      }
    }
  ],
  "types": {
    "WeatherConfig": {
      "location_name": "string",
      "open_weather_api_key": "string"
    },
    "CustomWeatherResponse": {
      "location_name": "string",
      "weather": "string"
    }
  }
}

The most interesting bit is in the steps section, where the mapping between inputs and outputs of different actions happens. For example:

"lat": "{{steps.get_coordinates.outputs[0].lat}}"

means that the outputs of the get_coordinates step will be used to resolve the "lat" property of the input that's going to be used in the get_weather step. Pretty simple, no?