Now that you've setup the command line utilities and gotten a taste of running Cloud Functions from the Web Console, it's time to write some code and deploy it!
Goals:
- Get used to using the CLI to build, deploy and debug development of Cloud Functions, and the structure of Cloud Function code.
- Learn how to:
- Examine the source for a Cloud Function and write one
- Build it
- Deploy it
- Look at logs messages
Go to the exercise1 folder, then:
-
mvn package -
ibmcloud fn action create helloJava target/hello-world-java.jar --main com.example.FunctionApp -
ibmcloud fn action invoke --result helloJava --param name <YOUR_NAME>
(please use YOUR_NAME)
You should see:
{
"greetings": "Hello <YOUR_NAME>"
}
"--result" means just show the results. Omit that, and see what you get back :)
This also adds the "--blocking" flag, discussed below.
- We're using the GSON library to work with JSON in Java
- Cloud Functions need a single "main" method with JSON in and JSON out:
public static JsonObject main(JsonObject args)
- We use the GSON library to parse the JSON args (params) and to create a response in JSON
So far we've just been creating JSON return values. What if we want to return some HTML?
-
Create a new class, called WebHello.java (it's OK to copy FunctionApp.java)
-
Change the code so that the response has a body with some HTML, like so:
response.addProperty("body", "<html><body><h3>" + result + "</h3></body></html>");
- Create a web-enabled Cloud Function using this command:
ibmcloud fn action create webHello target/hello-world-java.jar --main com.example.WebHello --web true
- Use the command from the previous section to get its URL
ibmcloud fn action get webHello --url
- Invoke it by pasting the URL into the browser. If you appended .json to it, you'll get the it in json format. Do not append .json to it - and you'll see an a message wrapped in an H3 tag!
- What about the name parameter this Cloud Function takes? Append this to the URL:
webHello?name=Pratik
Of course, put your name instead of mine :)
Our objectives in this exercise:
- Get used to using the CLI to build, deploy and debug development of Cloud Functions, and the structure of Cloud Function code.
- Learn how to:
- Examine the source for a Cloud Function and write one
- Build it
- Deploy it
- Look at logs messages
Please ask your friendly workshop instructor if you have any questions!
So you've finished before everyone else? No problem, here's some more stuff you can dive into!
- Create a more sophisticated Cloud Function called Recipe:
- Take an parameter called "dish"
- Take one of these three as valid input for types of dishes: pizza, pasta, chips
- Return a properly formatted JSON object with the ingredients for each dish. Example output for pizza:
{"ingredients" : ["dough", "cheese", "tomato sauce"]
- Create a HTML Cloud Function that sends an HTML page where you can pick from our foods: dishes: pizza, pasta, chips
- User selects one of these, and sends to the above Cloud Fn with the param of "dish"
- Convert the Cloud Function to return HTML and show the list of ingredients properly formatted