api-with-cronjob

HTTP API with CronJob

This sample illustrates how you can use the Spin Command Trigger to one time commands with Spin.

In the context of Kubernetes we can turn one-time commands into Jobs and CronJobs to perform individual tasks once or on a schedule.

The sample consists of two Spin Apps:

• API: A simple HTTP API that interacts with a key-value store
• CRON: A command app which wipes data from the key-value store

The API exposes the following endpoints

• GET /value - Returns the value of a counter from key-value store
• POST /value - Increments the counter in key-value store by 1
• DELETE /value - Removes the counter from the key-value store
• GET / - Prints available API endpoints

The Command App leverages Spin's key-value store API to load all keys available in the key-value store and deletes them.

Supported Platforms

• Local (spin up)
• SpinKube
• Fermyon Platform for Kubernetes

Prerequisites

To use this sample you must have

• Rust installed on your machine
  • The wasm32-wasi target for Rust installed (rustup target add wasm32-wasi)
• Spin CLI installed on your machine
• Command Trigger Plugin must be installed

Running the Sample

Local (spin up)

Follow the steps outlined below to run the API and the Command App:

• Start the API using spin up -f spin.toml --runtime-config-file ./local.rtc.toml
• Increment the counter by sending POST requests to /value: curl -X POST localhost:3000/value
• Check the value of the counter using curl localhost:3000/value (you should see a value other than 0)
• Run the Command App from a clean terminal instance using spin up -f spin-cron.toml --runtime-config-file ./local.rtc.toml
• Check the value of the counter using curl localhost:3000/value (it should now return 0)

Running on Kubernetes with SpinKube

The k8s folder contains a deploy.sh script that you can use to deploy the sample to your Kubernetes cluster.

You must have SpinKube installed

The script itself deploys the following artifacts to your cluster:

• Redis will be deployed to the redis namespace
• The Runtime Configuration File will be stored in the rtc secret in the default namespace
• The API will be deployed to the default namespace
• The Command App will be deployed as a CronJob to the default namespace and will be executed every 2nd minute