Cognito PreTokenGen Event (#95)

* Adds support for pretokengen event.

* link to the cognito events README files.

* Iam -> IAM

* Updated sample data with dummy values

copied from

* fix json synx error

Author: parsnips

events/README.md

@@ -18,6 +18,12 @@ This package provides input types for Lambda functions that process AWS events.
 
 [Cognito Events](README_Cognito.md)
 
+[Cognito PostConfirmation](README_Cognito_UserPools_PostConfirmation.md)
+
+[Cognito PreSignup](README_Cognito_UserPools_PreSignup.md)
+
+[Cognito PreTokenGen](README_Cognito_UserPools_PreTokenGen.md)
+
 [Config Events](README_Config.md)
 
 [DynamoDB Events](README_DynamoDB.md)

events/README_Cognito_UserPools_PreTokenGen.md

@@ -0,0 +1,26 @@
+# Sample Function
+
+The following is a sample Lambda function that receives Amazon Cognito User Pools pre-token-gen event as an input and writes some of the record data to CloudWatch Logs. (Note that by default anything written to Console will be logged as CloudWatch Logs events.)
+
+Please see instructions for setting up the Cognito triggers at https://docs.aws.amazon.com/cognito/latest/developerguide/cognito-user-identity-pools-working-with-aws-lambda-triggers.html .
+
+```go
+package main
+
+import (
+    "fmt"
+
+    "github.com/aws/aws-lambda-go/lambda"
+    "github.com/aws/aws-lambda-go/events"
+)
+
+func handler(event events.CognitoEventUserPoolsPreTokenGen) (events.CognitoEventUserPoolsPreTokenGen, error) {
+    fmt.Printf("PreTokenGen of user: %s\n", event.UserName)
+    event.Response.ClaimOverrideDetails.ClaimsToSupress = []string{"family_name"}
+    return event, nil
+}
+
+func main() {
+  lambda.Start(handler)
+}
+```

events/cognito.go

@@ -36,6 +36,14 @@ type CognitoEventUserPoolsPostConfirmation struct {
 	Response CognitoEventUserPoolsPostConfirmationResponse `json:"response"`
 }
 
+// CognitoEventUserPoolsPreTokenGen is sent by AWS Cognito User Pools when a user attempts to retrieve
+// credentials, allowing a Lambda to perform insert, supress or override claims
+type CognitoEventUserPoolsPreTokenGen struct {
+	CognitoEventUserPoolsHeader
+	Request  CognitoEventUserPoolsPreTokenGenRequest  `json:"request"`
+	Response CognitoEventUserPoolsPreTokenGenResponse `json:"response"`
+}
+
 // CognitoEventUserPoolsCallerContext contains information about the caller
 type CognitoEventUserPoolsCallerContext struct {
 	AWSSDKVersion string `json:"awsSdkVersion"`
@@ -73,3 +81,28 @@ type CognitoEventUserPoolsPostConfirmationRequest struct {
 // CognitoEventUserPoolsPostConfirmationResponse contains the response portion of a PostConfirmation event
 type CognitoEventUserPoolsPostConfirmationResponse struct {
 }
+
+// CognitoEventUserPoolsPreTokenGenRequest contains request portion of PreTokenGen event
+type CognitoEventUserPoolsPreTokenGenRequest struct {
+	UserAttributes     map[string]string  `json:"userAttributes"`
+	GroupConfiguration GroupConfiguration `json:"groupConfiguration"`
+}
+
+// CognitoEventUserPoolsPreTokenGenResponse containst the response portion of  a PreTokenGen event
+type CognitoEventUserPoolsPreTokenGenResponse struct {
+	ClaimsOverrideDetails ClaimsOverrideDetails `json:"claimsOverrideDetails"`
+}
+
+// ClaimsOverrideDetails allows lambda to add, supress or override claims in the token
+type ClaimsOverrideDetails struct {
+	GroupOverrideDetails  GroupConfiguration `json:"groupOverrideDetails"`
+	ClaimsToAddOrOverride map[string]string  `json:"claimsToAddOrOverride"`
+	ClaimsToSuppress      []string           `json:"claimsToSuppress"`
+}
+
+// GroupConfiguration allows lambda to override groups, roles and set a perferred role
+type GroupConfiguration struct {
+	GroupsToOverride   []string `json:"groupsToOverride"`
+	IAMRolesToOverride []string `json:"iamRolesToOverride"`
+	PreferredRole      *string  `json:"preferredRole"`
+}

events/cognito_test.go

@@ -85,3 +85,29 @@ func TestCognitoEventUserPoolsPostConfirmationMarshaling(t *testing.T) {
 
 	test.AssertJsonsEqual(t, inputJSON, outputJSON)
 }
+
+func TestCognitoEventUserPoolsPreTokenGenMarshalingMalformedJson(t *testing.T) {
+	test.TestMalformedJson(t, CognitoEventUserPoolsPreTokenGen{})
+}
+
+func TestCognitoEventUserPoolsPreTokenGenMarshaling(t *testing.T) {
+	// read json from file
+	inputJSON, err := ioutil.ReadFile("./testdata/cognito-event-userpools-pretokengen.json")
+	if err != nil {
+		t.Errorf("could not open test file. details: %v", err)
+	}
+
+	// de-serialize into CognitoEvent
+	var inputEvent CognitoEventUserPoolsPreTokenGen
+	if err := json.Unmarshal(inputJSON, &inputEvent); err != nil {
+		t.Errorf("could not unmarshal event. details: %v", err)
+	}
+
+	// serialize to json
+	outputJSON, err := json.Marshal(inputEvent)
+	if err != nil {
+		t.Errorf("could not marshal event. details: %v", err)
+	}
+
+	test.AssertJsonsEqual(t, inputJSON, outputJSON)
+}

events/testdata/cognito-event-userpools-pretokengen.json

@@ -0,0 +1,36 @@
+{
+  "version": "1",
+  "triggerSource": "PreTokenGen",
+  "region": "region",
+  "userPoolId": "userPoolId",
+  "userName": "userName",
+  "callerContext": {
+    "awsSdkVersion": "calling aws sdk with version",
+    "clientId": "apps client id"
+  },
+  "request": {
+    "userAttributes": {
+      "email": "email",
+      "phone_number": "phone_number"
+    },
+    "groupConfiguration": {
+      "groupsToOverride": ["group-A", "group-B", "group-C"],
+      "iamRolesToOverride": ["arn:aws:iam::XXXXXXXXXXXX:role/sns_callerA", "arn:aws:iam::XXXXXXXXX:role/sns_callerB", "arn:aws:iam::XXXXXXXXXX:role/sns_callerC"],
+      "preferredRole": "arn:aws:iam::XXXXXXXXXXX:role/sns_caller"
+    }
+  },
+  "response": {
+    "claimsOverrideDetails": {
+      "claimsToAddOrOverride": {
+        "attribute_key2": "attribute_value2",
+        "attribute_key": "attribute_value"
+      },
+      "claimsToSuppress": ["email"],
+      "groupOverrideDetails": {
+        "groupsToOverride": ["group-A", "group-B", "group-C"],
+        "iamRolesToOverride": ["arn:aws:iam::XXXXXXXXXXXX:role/sns_callerA", "arn:aws:iam::XXXXXXXXX:role/sns_callerB", "arn:aws:iam::XXXXXXXXXX:role/sns_callerC"],
+        "preferredRole": "arn:aws:iam::XXXXXXXXXXX:role/sns_caller"
+      }
+    }
+  }
+}