# Example EventBridge custom event patterns for different use cases
<a name="monitor-groups-example-eventbridge-filters"></a>

The following example EventBridge custom event patterns filter the events generated by Resource Groups to only those that you are interested in for a specific event rule and target.

In the following code examples, if a specific group or resource is needed, replace each *user input placeholder* with your own information.

All Resource Groups events  

```
{
    "source": [ "aws.resource-groups" ]
}
```

Group state or membership change events  
The following code example is for all group *state* changes.  

```
{
    "source": [ "aws.resource-groups" ],
    "detail-type": [ "ResourceGroups Group State Change " ]
}
```
The following code example is for all group *membership* changes.  

```
{
    "source": [ "aws.resource-groups" ],
    "detail-type": [ "ResourceGroups Group Membership Change" ]
}
```

Events for a specific group  

```
{
    "source": [ "aws.resource-groups" ],
    "detail": {
        "group": {
            "arn": [ "my-group-arn" ]
        }
    }
}
```
The previous example captures changes to the specified group. The following example does the same and also captures changes when the group is a member resource of another group.  

```
{
    "source": [ "aws.resource-groups" ],
    "resources": [ "my-group-arn" ]
}
```

Events for a specific resource  
You can filter only group membership change events for specific member resources.  

```
{
    "source": [ "aws.resource-groups" ],
    "detail-type": [ "ResourceGroups Group Membership Change " ],
    "resources": [ "arn:aws:ec2:us-east-1:123456789012:instance/i-b188560f" ]
}
```

Events for a specific resource type  
You can use prefix matching with ARNs to match events for a specific resource type.  

```
{
    "source": [ "aws.resource-groups" ],
    "resources": [
        { "prefix": "arn:aws:ec2:us-east-1:123456789012:instance" } 
    ]
}
```
Alternatively, you can use exact matching by using `resource-type` identifiers, potentially matching on more than one type concisely. Unlike the previous example, the following example matches only group membership change events because group state change events don't include a `resources` field in their `detail` field.  

```
{
    "source": [ "aws.resource-groups" ],
    "detail": {
        "resources": {
                "resource-type": [ "AWS::EC2::Instance", "AWS::EC2::Volume" ]
         }
    }
}
```

All resource removal events  

```
{
    "source": [ "aws.resource-groups" ],
    "detail-type": [ "ResourceGroups Group Membership Change" ],
    "detail": {
        "resources": {
                "membership-change": [ "remove" ]
        }
    }
}
```

All resource removal events for a specific resource  

```
 {
    "source": [ "aws.resource-groups" ],
    "detail-type": [ "ResourceGroups Group Membership Change" ],
    "detail": {
        "resources": {
                "membership-change": [ "remove" ],
                "arn": [ "arn:aws:ec2:us-east-1:123456789012:instance/i-b188560f" ]
         }
    }
}
```
You can't use the **top-level** `resources` array that was used in the first example in this section for this type of event filtering. That's because a resource in the top-level `resources` element might be a resource being added to a group and the event would still match. In other words, the following code example might return unexpected events. Instead, use the syntax shown in the previous example.  

```
{
    "source": [ "aws.resource-groups" ],
    "detail-type": [ "ResourceGroups Group Membership Change" ],
    "resources": [ "arn:aws:ec2:us-east-1:123456789012:instance/i-b188560f" ],
    "detail": {
        "resources": {
                "membership-change": [ "remove" ]
         }
     }
}
```