feat: add post confirmation lambda hook

signup-lambda/.gitignore

@@ -0,0 +1 @@
+target

signup-lambda/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "signup-lambda"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+
+lambda_runtime = "1.0.1"
+aws-sdk-cognitoidentityprovider = "1.105.0"
+serde = "1"
+tokio = { version = "1", features = ["macros"] }
+aws-config = "1.8.12"

signup-lambda/README.md

@@ -0,0 +1,52 @@
+# Introduction
+
+signup-lambda is a Rust project that implements an AWS Lambda function in Rust.
+
+## Prerequisites
+
+- [Rust](https://www.rust-lang.org/tools/install)
+- [Cargo Lambda](https://www.cargo-lambda.info/guide/installation.html)
+
+## Building
+
+To build the project for production, run `cargo lambda build --release`. Remove the `--release` flag to build for development.
+
+Read more about building your lambda function in [the Cargo Lambda documentation](https://www.cargo-lambda.info/commands/build.html).
+
+## Testing
+
+You can run regular Rust unit tests with `cargo test`.
+
+If you want to run integration tests locally, you can use the `cargo lambda watch` and `cargo lambda invoke` commands to do it.
+
+First, run `cargo lambda watch` to start a local server. When you make changes to the code, the server will automatically restart.
+
+Second, you'll need a way to pass the event data to the lambda function.
+
+You can use the existent [event payloads](https://github.com/awslabs/aws-lambda-rust-runtime/tree/main/lambda-events/src/fixtures) in the Rust Runtime repository if your lambda function is using one of the supported event types.
+
+You can use those examples directly with the `--data-example` flag, where the value is the name of the file in the [lambda-events](https://github.com/awslabs/aws-lambda-rust-runtime/tree/main/lambda-events/src/fixtures) repository without the `example_` prefix and the `.json` extension.
+
+```bash
+cargo lambda invoke --data-example apigw-request
+```
+
+For generic events, where you define the event data structure, you can create a JSON file with the data you want to test with. For example:
+
+```json
+{
+    "command": "test"
+}
+```
+
+Then, run `cargo lambda invoke --data-file ./data.json` to invoke the function with the data in `data.json`.
+
+
+Read more about running the local server in [the Cargo Lambda documentation for the `watch` command](https://www.cargo-lambda.info/commands/watch.html).
+Read more about invoking the function in [the Cargo Lambda documentation for the `invoke` command](https://www.cargo-lambda.info/commands/invoke.html).
+
+## Deploying
+
+To deploy the project, run `cargo lambda deploy`. This will create an IAM role and a Lambda function in your AWS account.
+
+Read more about deploying your lambda function in [the Cargo Lambda documentation](https://www.cargo-lambda.info/commands/deploy.html).

signup-lambda/src/handler.rs

@@ -0,0 +1,76 @@
+use lambda_runtime::LambdaEvent;
+use aws_sdk_cognitoidentityprovider::Client;
+use aws_config::BehaviorVersion;
+use serde::{Serialize, Deserialize};
+use std::collections::HashMap;
+use aws_sdk_cognitoidentityprovider::error::ProvideErrorMetadata;
+
+#[derive(Serialize, Deserialize, Debug)]
+#[serde(rename_all = "camelCase")]
+pub(crate) struct PostConfirmationEvent {
+    version: String,
+    trigger_source: String,
+    region: String,
+    user_pool_id: String,
+    user_name: String,
+    caller_context: CallerContext,
+    request: Request,
+    response: Response
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+#[serde(rename_all = "camelCase")]
+pub(crate) struct CallerContext {
+    client_id: String,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+#[serde(rename_all = "camelCase")]
+pub(crate) struct Request {
+    user_attributes: HashMap<String, String>,
+}
+
+#[derive(Serialize, Deserialize, Debug)]
+#[serde(rename_all = "camelCase")]
+pub(crate) struct Response {}
+
+fn get_error_message(err: impl ProvideErrorMetadata) -> String {
+    err.message().unwrap_or("An unknown error occurred").to_string()
+}
+
+async fn add_user_to_group(provider: Client, user_id: String, group_name: impl Into<String>) -> Result<(), String> {
+    let group_name = group_name.into();
+    println!("Adding user {} to group {}", user_id, group_name);
+    match provider
+        .admin_add_user_to_group()
+        .user_pool_id("us-east-1_Lfjuy5zaM")
+        .username(user_id)
+        .group_name(group_name)
+        .send()
+        .await
+    {
+        Ok(_) => Ok(()),
+        Err(err) => Err(get_error_message(err)),
+    }
+}
+
+pub(crate) async fn handler(event: LambdaEvent<PostConfirmationEvent>) -> Result<PostConfirmationEvent, String> {
+    println!("Found event: {:?}", event.payload);
+
+    let user_id = event.payload.request.user_attributes.get("sub").unwrap().to_string();
+    let config = aws_config::load_defaults(BehaviorVersion::latest()).await;
+    let client = Client::new(&config);
+
+    // Check the client ID of the request to assign the user to the correct location.
+    let res = match event.payload.caller_context.client_id.as_str() {
+        "10jr2h3vtpu9n7gj46pvg5qo2q" => add_user_to_group(client, user_id, "ScholarshipStudents").await,
+        "56c2bqvl021rv8d5mq36blt7jv" => add_user_to_group(client, user_id, "ScholarshipProviders").await,
+        _ => Err("Invalid client ID, denying all user access.".to_string()),
+    };
+
+    if res.is_ok() {
+        Ok(event.payload)
+    } else {
+        Err(res.unwrap_err())
+    }
+}

signup-lambda/src/main.rs

@@ -0,0 +1,11 @@
+use lambda_runtime::{run, service_fn, tracing, Error};
+mod handler;
+
+use handler::handler as function_handler;
+
+#[tokio::main]
+async fn main() -> Result<(), Error> {
+    tracing::init_default_subscriber();
+
+    run(service_fn(function_handler)).await
+}