Rewrite heartbeat Lambda

Cargo.toml

@@ -12,7 +12,12 @@ edition = "2018"
 name = "echo"
 path = "echo/lambda.rs"
 
+[[bin]]
+name = "heartbeat"
+path = "heartbeat/lambda.rs"
+
 [dependencies]
+hyper = "0.14"
 lambda_runtime = "0.4"
 log = "0.4"
 serde_json = "1.0"

heartbeat/lambda.rs

@@ -0,0 +1,30 @@
+use hyper::{Body, Client, Request, Uri};
+use lambda_runtime::{handler_fn, Context, Error};
+use serde_json::Value;
+use std::env;
+
+#[tokio::main]
+async fn main() -> Result<(), Error> {
+    simple_logger::init_with_level(log::Level::Trace)?;
+    lambda_runtime::run(handler_fn(handler)).await?;
+    Ok(())
+}
+
+async fn handler(_: Value, _: Context) -> Result<(), Error> {
+    let endpoint: Uri = env::var("HEARTBEAT_ENDPOINT")
+        .expect("heartbeat endpoint must be set")
+        .parse()
+        .unwrap();
+
+    let req = Request::get(endpoint)
+        .header("User-Agent", "dilbert-feed-rust")
+        .body(Body::empty())
+        .unwrap();
+
+    let resp = Client::new().request(req).await?;
+    if !resp.status().is_success() {
+        return Err(format!("HTTP error: {}", resp.status()).into());
+    };
+
+    Ok(())
+}

index.ts

@@ -60,9 +60,9 @@ export class DilbertFeedStack extends cdk.Stack {
     const heartbeatEndpoint = ssm.StringParameter.valueForStringParameter(this, `/${id}/heartbeat-endpoint`)
     const heartbeat = new lambda.Function(this, 'HeartbeatFunc', {
       functionName: `${id}-heartbeat`,
-      code: lambda.Code.fromAsset('heartbeat'),
-      handler: 'lambda.handler',
-      runtime: lambda.Runtime.NODEJS_12_X,
+      code: lambda.Code.fromAsset('bin/heartbeat'),
+      handler: 'bootstrap',
+      runtime: lambda.Runtime.PROVIDED,
       memorySize: 128,
       timeout: cdk.Duration.seconds(10),
       logRetention: logs.RetentionDays.ONE_MONTH,