Input parameters

I use “DescribeInstances” for this example.

First you have to find out the parameters for the API call. With VSCode you just klick on the documentation link of the import line.

There you navigate to the type client and find the call. If you know the aws cli call, which is:

aws ec2 describe-instances

You just change it to CamelCase DescribeInstances and delete the “-”.

The definition for this ec2 call is:

func (c *Client) DescribeInstances(ctx context.Context, params *DescribeInstancesInput, optFns ...func(*Options)) (*DescribeInstancesOutput, error)
Part  Meaning
(c *Client) This is a function operating on the structure client
DescribeInstances Name of the function
ctx context.Context The context rarely needed, usually its *context.Todo()
params *DescribeInstancesInput type of the input variable called params
optFns …func(*Options) means 0..n time this input parameter, most of the times not needed
*DescribeInstancesOutput  Definition of the type you get in return
error  Error, check for nil=ok

Fast way to find parameters

Inside the structure in VSCode you get a code action, which fills all parameters for you.

The code action generates:

	parms := &ec2.DescribeInstancesInput{
		NextToken:   new(string),
		Filters:     []types.Filter{},
		InstanceIds: []string{},
		MaxResults:  new(int32),
		NextToken:   new(string),

In this example we just cut MaxResults to 10.

The parameters are documented in detail - just click on the documentation link inside VSCode (or other editors)

To code the parameters we add this import:


The aws package gives utility functions for all pointers.

Let me give you two examples:

A pointer to bool:

		DryRun:      new(bool),
        // becomes
		DryRun:     aws.Bool(false),

A pointer to int32:

		MaxResults:  new(int32),
        MaxResults: aws.Int32(10),

So the parameter section for this example looks like:

	parms := &ec2.DescribeInstancesInput{
		MaxResults: aws.Int32(10),

Now that we have the parameters, we can call the service.

See also


See the full source on github.