A simple weather application intended to be run on a Raspberry Pi. This application interacts with the National Weather Service (NWS) API, and retrieves data to be served by the application out of a DataStax Astra DB database. It also interacts with a DataStax Langflow Agent flow. Both the database and agent must be built ahead of time.
This application requires a running Astra DB cloud database. The "free tier" of Astra DB should provide more than enough resources to run the application. If the Astra database is "hibernated," it will need to be "resumed" before running the applicaiton.
It is recommended to name the keyspace weatherapp. Really, the keyspace can be named anything, but any changes need to be reflected in the controller code.
Inside the keyspace, create a non-vector-enabled collection named weather_data.
A token from an appropriately-scoped role is required to be generated, as is the Astra Database's specific Data API endpoint.
The Langflow Agent flow can be quickly created by creating a new flow, and selecting the "Simple Agent" template. That's really all there is to it (other than specifying the API token for your model provider). Be sure to click on the "API" tab, and make note of the flow's Langflow API endpoint.
This application requires the following environment variables to be set:
- ASTRA_DB_APP_TOKEN - The token obtained from Astra DB.
- ASTRA_DB_API_ENDPOINT - The Data API endpoint for the specific instance of Astra DB.
- ASTRA_LANGFLOW_URL - The Langflow API endpoint for the specific flow.
- LANGFLOW_ORG - The organization ID for the Langflow project.
- LANGFLOW_TOKEN - An access token specific to the Langflow project.
In a Mac/Linux/Raspberry Pi OS environment, the environment varaibles can be set from a terminal like this (example):
export ASTRA_DB_API_ENDPOINT=https://not-real-us-east1.apps.astra.datastax.com
export ASTRA_DB_APP_TOKEN=AstraCS:wtqNOTglg:725REAL238dEITHER563486d
export ASTRA_LANGFLOW_URL=https://api.langflow.astra.datastax.com/lf/6f-not-real-9493/api/v1/run/060d2-not-real-caef?stream=false
export LANGFLOW_ORG=ca2fd34f-fnot4-4realb-ab78-4fblahblahac
export LANGFLOW_TOKEN=AstraCS:AarNOTglg:725REAL238dEITHER5632112
- Java 17 (JDK)
- Maven
- dependencies for Spring Boot and Vaadin
mvn clean install -Pproduction
java -jar target/weatherapp-0.0.1-SNAPSHOT.jar
The Weather Application is exposed locally at http://127.0.0.1:8080. It also has restful endpoints which allow it to both fetch and display data. When the application first comes up, it will not show any data. To remedy this, click the "Refresh" button. If data is present for the current month, the most-recent weather reading will be displayed. If there is no data for the current month, nothing will be displayed. See the Loading Data step below.
Note: The station code of "kmsp" (for the Minneapolis/St. Paul International Airport) is the default in this application. Additional station codes can be found at the official NWS website: https://forecast.weather.gov, such as "knyc" (for New York City's Central Park weather station).
The most-recent reading from the NWS can be loaded into the application by invoking the following PUT endpoint (Weather Application needs to be running): http://127.0.0.1:8080/weather/latest/station/kmsp. This can be run using the curl utility:
curl -X PUT http://127.0.0.1:8080/weather/astradb/api/latest/station/kmsp
In addition to the user interface, the most-recently loaded weather reading from the NWS (stored in the Weather Application's database) can be viewed on the following GET endpoint: http://127.0.0.1:8080/weather/latest/station/kmsp/month/202503. Note that the month is specified in the YYYYMM format.
curl -X GET http://127.0.0.1:8080/weather/astradb/api/latest/station/kmsp/month/202503