Creating a S2S authorization to work with the IBM® Event Streams for IBM Cloud® service

Use IBM Cloud® Identity and Access Management (IAM) to create an authorization that grants IBM Cloud Logs access to the IBM® Event Streams for IBM Cloud® service.

Before you begin

Read about Managing authorizations to grant access between services.
You must have access to the target service to manage authorization between services. For more information, see Permissions to manage authorizations.

The target service is located always in the account where the authorization is created.

The autorization that you define for the IBM Cloud Logs service requires that you have Administrator role for the IBM® Event Streams for IBM Cloud® target.

Service access roles

You can select any of the following roles that the source can use to interact with the target. You can grant only the level of access that you have as a user of the target that you selected.

Writer: You must grant Writer role to handle source integration with the IBM® Event Streams for IBM Cloud® service.

Creating an authorization through the console

Complete the following steps:

In the IBM Cloud console, click Manage > Access (IAM), and select Authorizations.
Click Create.
Select a source account.

If the source service that needs access to the target service is in this account, select This account.

If the source service that needs access to the target service is in a different account, select Other account. Then, enter the account ID of the source account.
Select Cloud Logs as the source service. Then, set the scope of the access.

Select All resources to grant access for all instances in the account.

Select Source service instance to grant access to 1 IBM Cloud Logs instance.
Select Event Streams as the target service. Then, set the scope of the access.

To grant access to all IBM® Event Streams for IBM Cloud® instances and resources in the account, select All resources.

To grant access to a specific instance, select single instance by configuring Resources based on selected attributes > Service Instance.
In the Service Access section, select the role to assign access to the source service that accesses the target service.

Select Writer to authorize streaming to IBM® Event Streams for IBM Cloud®.
Click Authorize.

If you create an authorization between a service in another account and a target service in your current account, you need to have access only to the target resource. For the source account, you need only the account number.

Creating an authorization by using the CLI

Run the following command to create an authorization for the IBM Cloud Logs service.

ibmcloud iam authorization-policy-create logs messagehub "Writer" [--source-service-instance-name SOURCE_SERVICE_INSTANCE_NAME | --source-service-instance-id SOURCE_SERVICE_INSTANCE_ID] [--target-service-instance-name TARGET_SERVICE_INSTANCE_NAME | --target-service-instance-id TARGET_SERVICE_INSTANCE_ID]

For more information about all of the parameters that are available for this command, see ibmcloud iam authorization-policy-create.

Creating an authorization by using Terraform

Before you can create an authorization by using Terraform, make sure that you have completed the following:

Install the Terraform CLI and configure the IBM Cloud Provider plug-in for Terraform. For more information, see the tutorial for Getting started with Terraform on IBM Cloud. The plug-in abstracts the IBM Cloud APIs that are used to complete this task.
Create a Terraform configuration file that is named main.tf. In this file, you define resources by using HashiCorp Configuration Language. For more information, see the Terraform documentation.

Use the following steps to create an authorization by using Terraform:

Create an authorization policy between services by using the ibm_iam_authorization_policy resource argument in your main.tf file.

The following example creates an authorization between 2 services:
```
resource "ibm_iam_authorization_policy" "policy" {
 source_service_name = "logs"
 target_service_name = "messagehub"
 roles               = ["Writer"]
 description         = "Authorization Policy"
 transaction_id     = "terraformAuthorizationPolicy"
}
```
The following example creates an authorization between 2 specific service instances:
```
resource "ibm_iam_authorization_policy" "policy" {
  source_service_name         = "logs"
  source_resource_instance_id = ibm_resource_instance.instance1.guid
  target_service_name         = "messagehub"
  target_resource_instance_id = ibm_resource_instance.instance2.guid
  roles                       = ["Writer"]
}
```
The ibm_iam_authorization_policy resource requires the source service, target service, and role. The source service is granted access to the target service, and the role is the level of permission that the access allows. Optionally, you can add a description for the authorization and a transaction ID.
- You can provide a target_resource_instance_id to scope a IBM® Event Streams for IBM Cloud® target instance.
- For more examples, see the Terraform documentation for authorization resources.
After you finish building your configuration file, initialize the Terraform CLI. For more information, see Initializing Working Directories.
```
terraform init
```
Provision the resources from the main.tf file. For more information, see Provisioning Infrastructure with Terraform.
1. Run terraform plan to generate a Terraform execution plan to preview the proposed actions.
```
terraform plan
```
2. Run terraform apply to create the resources that are defined in the plan.
```
terraform apply
```

Creating an authorization by using the API

To authorize a source service access to a target service, use the IAM Policy Management API. See the following API example for create a policy method with the type=authorization specified for a event-notifications target.

The supported attributes for creating an authorization policy depend on what each service supports. For more information about the supported attributes for each service, see the documentation for the services that you're using.

curl --request POST \
  --url https://iam.cloud.ibm.com/v1/policies \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
    "type": "authorization",
    "subjects": [
        {
            "attributes": [
                {
                    "name": "accountId",
                    "value": "<account-id>"
                },
                {
                    "name": "serviceName",
                    "value": "logs"
                }
            ]
        }
    ],
    "roles": [
        {
            "role_id": "crn:v1:bluemix:public:event-notifications::::serviceRole:Reader"
        }
    ],
    "resources": [
        {
            "attributes": [
                {
                    "name": "serviceName",
                    "value": "messagehub"
                }
            ]
        }
    ]
}'