Policy structure

The following topics explain the structure of an IAM policy.

Policy syntax

An IAM policy is a JSON document that consists of one or more statements. Each statement is structured as follows.

{
  "Statement":[{
    "Effect":"effect",
    "Action":"action",
    "Resource":"arn",
    "Condition":{
      "condition":{
    "key":"value"
    }
      }
    }
  ]
}

There are various elements that make up a statement:

• Effect: The effect can be Allow or Deny. By default, users don't have permission to use resources and API actions. So, all requests are denied. An explicit allow overrides the default. An explicit deny overrides any allows.

• Action: The action is the specific API action that you're granting or denying permission for. For instructions on how to specify the action, see Actions for AWS Batch.

• Resource: The resource that's affected by the action. With some AWS Batch API actions, you can include specific resources in your policy that can be created or modified by the action. To specify a resource in the statement, use its Amazon Resource Name (ARN). For more information, see Supported resource-level permissions for AWS Batch API actions and Amazon Resource Names for AWS Batch. If the AWS Batch API operation currently doesn't support resource-level permissions, include a wildcard (*) to specify that all resources can be affected by the action.

• Condition: Conditions are optional. They can be used to control when your policy is in effect.

For more information about example IAM policy statements for AWS Batch, see Creating AWS Batch IAM policies.

Actions for AWS Batch

In an IAM policy statement, you can specify any API action from any service that supports IAM. For AWS Batch, use the following prefix with the name of the API action: batch: (for example, batch:SubmitJob and batch:CreateComputeEnvironment).

To specify multiple actions in a single statement, separate each action with a comma.

"Action": ["batch:action1", "batch:action2"]

You can also specify multiple actions by including a wildcard (*). For example, you can specify all actions with a name that begins with the word "Describe."

"Action": "batch:Describe*"

To specify all AWS Batch API actions, include a wildcard (*).

"Action": "batch:*"

For a list of AWS Batch actions, see Actions in the AWS Batch API Reference.

Amazon Resource Names for AWS Batch

Each IAM policy statement applies to the resources that you specify using their Amazon Resource Names (ARNs).

An Amazon Resource Name (ARN) has the following general syntax:

arn:aws:[service]:[region]:[account]:resourceType/resourcePath

service

The service (for example, batch).

region

The AWS Region for the resource (for example, us-east-2).

account

The AWS account ID, with no hyphens (for example, 123456789012).

resourceType

The type of resource (for example, compute-environment).

resourcePath

A path that identifies the resource. You can use a wildcard (*) in your paths.

AWS Batch API operations currently support resource-level permissions on several API operations. For more information, see Supported resource-level permissions for AWS Batch API actions. To specify all resources, or if a specific API action doesn't support ARNs, include a wildcard (*) in the Resource element.

"Resource": "*"

Checking that users have the required permissions

Before you put an IAM policy into production, make sure that it grants users the permissions to use the specific API actions and resources that they need.

To do this, first create a user for testing purposes and attach the IAM policy to the test user. Then, make a request as the test user. You can make test requests in the console or with the AWS CLI.

Note

You can also test your policies by using the IAM Policy Simulator. For more information about the policy simulator, see Working with the IAM Policy Simulator in the IAM User Guide.

If the policy doesn't grant the user the permissions that you expected, or is overly permissive, you can adjust the policy as needed. Retest until you get the desired results.

Important

It can take several minutes for policy changes to propagate before they take effect. Therefore, we recommend that you allow at least five minutes to pass before you test your policy updates.

If an authorization check fails, the request returns an encoded message with diagnostic information. You can decode the message using the DecodeAuthorizationMessage action. For more information, see DecodeAuthorizationMessage in the AWS Security Token Service API Reference, and decode-authorization-message in the AWS CLI Command Reference.