oci-list-instances-java

Function that returns the list of instances in the calling Compartment

This function uses Resource Principals to securely authorize a function to make API calls to OCI services using the OCI Java SDK. It returns a list of all instances within the compartment that calls the function.

The function calls the following OCI Java SDK classes:

• ResourcePrincipalAuthenticationDetailsProvider to authenticate
• ComputeClient to interact with Compute

As you make your way through this tutorial, look out for this icon . Whenever you see it, it's time for you to perform an action.

Prerequisites

Before you deploy this sample function, make sure you have run steps A, B and C of the Oracle Functions Quick Start Guide for Cloud Shell

• A - Set up your tenancy
• B - Create application
• C - Set up your Cloud Shell dev environment

List Applications

Assuming you have successfully completed the prerequisites, you should see your application in the list of applications.

fn ls apps

Create or Update your Dynamic Group

In order to use other OCI Services, your function must be part of a dynamic group. For information on how to create a dynamic group, refer to the documentation.

When specifying the Matching Rules, we suggest matching all functions in a compartment with:

ALL {resource.type = 'fnfunc', resource.compartment.id = 'ocid1.compartment.oc1..aaaaaxxxxx'}

Create or Update IAM Policies

Create a new policy that allows the dynamic group to inspect instances in the functions related compartment.

Your policy should look something like this:

Allow dynamic-group <dynamic-group-name> to inspect instances in compartment <compartment-name>

e.g.

Allow dynamic-group demo-func-dyn-group to inspect instances in compartment demo-func-compartment

For more information on how to create policies, go here.

Review and customize your function

Review the following files in the current folder:

• pom.xml specifies all the dependencies for your function
• func.yaml that contains metadata about your function and declares properties
• src/main/java/com/example/fn/ComputeInstancesList.java which contains the Java code

The name of your function oci-list-instances-java is specified in func.yaml.

Deploy the function

In Cloud Shell, run the fn deploy command to build the function and its dependencies as a Docker image, push the image to the specified Docker registry, and deploy the function to Oracle Functions in the application created earlier:

fn -v deploy --app <app-name>

e.g.

fn -v deploy --app myapp

Test

Use the fn CLI to invoke your function with your app name and the compartment OCID:

echo -n '<compartment-ocid>' | fn invoke <app-name> <function-name>

e.g.

echo -n 'ocid1.compartment.oc1...2jn3htfoobar' | fn invoke myapp oci-list-instances-java

You should see a map of instances in your compartment appear on your terminal. Key is the OCID of the instance and value is a String representation of the Instance object.

Monitoring Functions

Learn how to configure basic observability for your function using metrics, alarms and email alerts:

• Basic Guidance for Monitoring your Functions