d/aws_iam_session_context: New data source

.changelog/19957.txt

@@ -0,0 +1,3 @@
+```release-note:new-data-source
+aws_iam_session_context
+```

aws/data_source_aws_caller_identity.go

@@ -39,7 +39,7 @@ func dataSourceAwsCallerIdentityRead(d *schema.ResourceData, meta interface{}) e
 	res, err := client.GetCallerIdentity(&sts.GetCallerIdentityInput{})
 
 	if err != nil {
-		return fmt.Errorf("Error getting Caller Identity: %w", err)
+		return fmt.Errorf("getting Caller Identity: %w", err)
 	}
 
 	log.Printf("[DEBUG] Received Caller Identity: %s", res)

aws/data_source_aws_iam_session_context.go

@@ -0,0 +1,128 @@
+package aws
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/aws/aws-sdk-go/aws/arn"
+	"github.com/aws/aws-sdk-go/service/iam"
+	"github.com/hashicorp/aws-sdk-go-base/tfawserr"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/resource"
+	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
+	"github.com/terraform-providers/terraform-provider-aws/aws/internal/service/iam/finder"
+	"github.com/terraform-providers/terraform-provider-aws/aws/internal/service/iam/waiter"
+	"github.com/terraform-providers/terraform-provider-aws/aws/internal/tfresource"
+)
+
+func dataSourceAwsIAMSessionContext() *schema.Resource {
+	return &schema.Resource{
+		Read: dataSourceAwsIAMSessionContextRead,
+
+		Schema: map[string]*schema.Schema{
+			"arn": {
+				Type:         schema.TypeString,
+				Required:     true,
+				ValidateFunc: validateArn,
+			},
+			"issuer_arn": {
+				Type:     schema.TypeString,
+				Computed: true,
+			},
+			"issuer_id": {
+				Type:     schema.TypeString,
+				Computed: true,
+			},
+			"issuer_name": {
+				Type:     schema.TypeString,
+				Computed: true,
+			},
+			"session_name": {
+				Type:     schema.TypeString,
+				Computed: true,
+			},
+		},
+	}
+}
+
+func dataSourceAwsIAMSessionContextRead(d *schema.ResourceData, meta interface{}) error {
+	conn := meta.(*AWSClient).iamconn
+
+	arn := d.Get("arn").(string)
+
+	d.SetId(arn)
+
+	roleName := ""
+	sessionName := ""
+	var err error
+
+	if roleName, sessionName = roleNameSessionFromARN(arn); roleName == "" {
+		d.Set("issuer_arn", arn)
+		d.Set("issuer_id", "")
+		d.Set("issuer_name", "")
+		d.Set("session_name", "")
+
+		return nil
+	}
+
+	var role *iam.Role
+
+	err = resource.Retry(waiter.PropagationTimeout, func() *resource.RetryError {
+		var err error
+
+		role, err = finder.Role(conn, roleName)
+
+		if !d.IsNewResource() && tfawserr.ErrCodeEquals(err, iam.ErrCodeNoSuchEntityException) {
+			return resource.RetryableError(err)
+		}
+
+		if err != nil {
+			return resource.NonRetryableError(err)
+		}
+
+		return nil
+	})
+
+	if tfresource.TimedOut(err) {
+		role, err = finder.Role(conn, roleName)
+	}
+
+	if err != nil {
+		return fmt.Errorf("unable to get role (%s): %w", roleName, err)
+	}
+
+	if role == nil || role.Arn == nil {
+		return fmt.Errorf("empty role returned (%s)", roleName)
+	}
+
+	d.Set("issuer_arn", role.Arn)
+	d.Set("issuer_id", role.RoleId)
+	d.Set("issuer_name", roleName)
+	d.Set("session_name", sessionName)
+
+	return nil
+}
+
+// roleNameSessionFromARN returns the role and session names in an ARN if any.
+// Otherwise, it returns empty strings.
+func roleNameSessionFromARN(rawARN string) (string, string) {
+	parsedARN, err := arn.Parse(rawARN)
+
+	if err != nil {
+		return "", ""
+	}
+
+	reAssume := regexp.MustCompile(`^assumed-role/.{1,}/.{2,}`)
+
+	if !reAssume.MatchString(parsedARN.Resource) || parsedARN.Service != "sts" {
+		return "", ""
+	}
+
+	parts := strings.Split(parsedARN.Resource, "/")
+
+	if len(parts) < 3 {
+		return "", ""
+	}
+
+	return parts[len(parts)-2], parts[len(parts)-1]
+}