Remove function config allocations per invocation. (#732)

Every invocation clones the function config. This allocates memory in the heap for no reason.

This change removes those extra allocations by wrapping the config into an Arc and sharing that between invocations.

Signed-off-by: David Calavera <[email protected]>

Author: calavera

Cargo.toml

@@ -1,4 +1,5 @@
 [workspace]
+resolver = "2"
 members = [
     "lambda-http",
     "lambda-integration-tests",

lambda-runtime/Cargo.toml

@@ -32,7 +32,7 @@ hyper = { version = "0.14.20", features = [
     "server",
 ] }
 futures = "0.3"
-serde = { version = "1", features = ["derive"] }
+serde = { version = "1", features = ["derive", "rc"] }
 serde_json = "^1"
 bytes = "1.0"
 http = "0.2"

lambda-runtime/src/lib.rs

@@ -23,6 +23,7 @@ use std::{
     future::Future,
     marker::PhantomData,
     panic,
+    sync::Arc,
 };
 use tokio::io::{AsyncRead, AsyncWrite};
 use tokio_stream::{Stream, StreamExt};
@@ -58,6 +59,8 @@ pub struct Config {
     pub log_group: String,
 }
 
+type RefConfig = Arc<Config>;
+
 impl Config {
     /// Attempts to read configuration from environment variables.
     pub fn from_env() -> Result<Self, Error> {
@@ -86,7 +89,7 @@ where
 
 struct Runtime<C: Service<http::Uri> = HttpConnector> {
     client: Client<C>,
-    config: Config,
+    config: RefConfig,
 }
 
 impl<C> Runtime<C>
@@ -127,8 +130,7 @@ where
                 continue;
             }
 
-            let ctx: Context = Context::try_from(parts.headers)?;
-            let ctx: Context = ctx.with_config(&self.config);
+            let ctx: Context = Context::try_from((self.config.clone(), parts.headers))?;
             let request_id = &ctx.request_id.clone();
 
             let request_span = match &ctx.xray_trace_id {
@@ -263,7 +265,10 @@ where
     trace!("Loading config from env");
     let config = Config::from_env()?;
     let client = Client::builder().build().expect("Unable to create a runtime client");
-    let runtime = Runtime { client, config };
+    let runtime = Runtime {
+        client,
+        config: Arc::new(config),
+    };
 
     let client = &runtime.client;
     let incoming = incoming(client);
@@ -294,15 +299,15 @@ mod endpoint_tests {
         },
         simulated,
         types::Diagnostic,
-        Error, Runtime,
+        Config, Error, Runtime,
     };
     use futures::future::BoxFuture;
     use http::{uri::PathAndQuery, HeaderValue, Method, Request, Response, StatusCode, Uri};
     use hyper::{server::conn::Http, service::service_fn, Body};
     use lambda_runtime_api_client::Client;
     use serde_json::json;
     use simulated::DuplexStreamWrapper;
-    use std::{convert::TryFrom, env, marker::PhantomData};
+    use std::{convert::TryFrom, env, marker::PhantomData, sync::Arc};
     use tokio::{
         io::{self, AsyncRead, AsyncWrite},
         select,
@@ -531,9 +536,12 @@ mod endpoint_tests {
         if env::var("AWS_LAMBDA_LOG_GROUP_NAME").is_err() {
             env::set_var("AWS_LAMBDA_LOG_GROUP_NAME", "test_log");
         }
-        let config = crate::Config::from_env().expect("Failed to read env vars");
+        let config = Config::from_env().expect("Failed to read env vars");
 
-        let runtime = Runtime { client, config };
+        let runtime = Runtime {
+            client,
+            config: Arc::new(config),
+        };
         let client = &runtime.client;
         let incoming = incoming(client).take(1);
         runtime.run(incoming, f).await?;
@@ -568,13 +576,13 @@ mod endpoint_tests {
 
         let f = crate::service_fn(func);
 
-        let config = crate::Config {
+        let config = Arc::new(Config {
             function_name: "test_fn".to_string(),
             memory: 128,
             version: "1".to_string(),
             log_stream: "test_stream".to_string(),
             log_group: "test_log".to_string(),
-        };
+        });
 
         let runtime = Runtime { client, config };
         let client = &runtime.client;

lambda-runtime/src/types.rs

@@ -1,4 +1,4 @@
-use crate::{Config, Error};
+use crate::{Error, RefConfig};
 use base64::prelude::*;
 use bytes::Bytes;
 use http::{HeaderMap, HeaderValue, StatusCode};
@@ -97,7 +97,7 @@ pub struct CognitoIdentity {
 /// are populated using the [Lambda environment variables](https://docs.aws.amazon.com/lambda/latest/dg/current-supported-versions.html)
 /// and [the headers returned by the poll request to the Runtime APIs](https://docs.aws.amazon.com/lambda/latest/dg/runtimes-api.html#runtimes-api-next).
 #[non_exhaustive]
-#[derive(Clone, Debug, Eq, PartialEq, Default, Serialize, Deserialize)]
+#[derive(Clone, Debug, Deserialize, Eq, PartialEq, Serialize)]
 pub struct Context {
     /// The AWS request ID generated by the Lambda service.
     pub request_id: String,
@@ -117,12 +117,14 @@ pub struct Context {
     /// Lambda function configuration from the local environment variables.
     /// Includes information such as the function name, memory allocation,
     /// version, and log streams.
-    pub env_config: Config,
+    pub env_config: RefConfig,
 }
 
-impl TryFrom<HeaderMap> for Context {
+impl TryFrom<(RefConfig, HeaderMap)> for Context {
     type Error = Error;
-    fn try_from(headers: HeaderMap) -> Result<Self, Self::Error> {
+    fn try_from(data: (RefConfig, HeaderMap)) -> Result<Self, Self::Error> {
+        let env_config = data.0;
+        let headers = data.1;
         let client_context: Option<ClientContext> = if let Some(value) = headers.get("lambda-runtime-client-context") {
             serde_json::from_str(value.to_str()?)?
         } else {
@@ -158,13 +160,20 @@ impl TryFrom<HeaderMap> for Context {
                 .map(|v| String::from_utf8_lossy(v.as_bytes()).to_string()),
             client_context,
             identity,
-            ..Default::default()
+            env_config,
         };
 
         Ok(ctx)
     }
 }
 
+impl Context {
+    /// The execution deadline for the current invocation.
+    pub fn deadline(&self) -> SystemTime {
+        SystemTime::UNIX_EPOCH + Duration::from_millis(self.deadline)
+    }
+}
+
 /// Incoming Lambda request containing the event payload and context.
 #[derive(Clone, Debug)]
 pub struct LambdaEvent<T> {
@@ -273,6 +282,8 @@ where
 #[cfg(test)]
 mod test {
     use super::*;
+    use crate::Config;
+    use std::sync::Arc;
 
     #[test]
     fn round_trip_lambda_error() {
@@ -292,6 +303,8 @@ mod test {
 
     #[test]
     fn context_with_expected_values_and_types_resolves() {
+        let config = Arc::new(Config::default());
+
         let mut headers = HeaderMap::new();
         headers.insert("lambda-runtime-aws-request-id", HeaderValue::from_static("my-id"));
         headers.insert("lambda-runtime-deadline-ms", HeaderValue::from_static("123"));
@@ -300,16 +313,18 @@ mod test {
             HeaderValue::from_static("arn::myarn"),
         );
         headers.insert("lambda-runtime-trace-id", HeaderValue::from_static("arn::myarn"));
-        let tried = Context::try_from(headers);
+        let tried = Context::try_from((config, headers));
         assert!(tried.is_ok());
     }
 
     #[test]
     fn context_with_certain_missing_headers_still_resolves() {
+        let config = Arc::new(Config::default());
+
         let mut headers = HeaderMap::new();
         headers.insert("lambda-runtime-aws-request-id", HeaderValue::from_static("my-id"));
         headers.insert("lambda-runtime-deadline-ms", HeaderValue::from_static("123"));
-        let tried = Context::try_from(headers);
+        let tried = Context::try_from((config, headers));
         assert!(tried.is_ok());
     }
 
@@ -338,7 +353,9 @@ mod test {
             "lambda-runtime-client-context",
             HeaderValue::from_str(&client_context_str).unwrap(),
         );
-        let tried = Context::try_from(headers);
+
+        let config = Arc::new(Config::default());
+        let tried = Context::try_from((config, headers));
         assert!(tried.is_ok());
         let tried = tried.unwrap();
         assert!(tried.client_context.is_some());
@@ -347,17 +364,20 @@ mod test {
 
     #[test]
     fn context_with_empty_client_context_resolves() {
+        let config = Arc::new(Config::default());
         let mut headers = HeaderMap::new();
         headers.insert("lambda-runtime-aws-request-id", HeaderValue::from_static("my-id"));
         headers.insert("lambda-runtime-deadline-ms", HeaderValue::from_static("123"));
         headers.insert("lambda-runtime-client-context", HeaderValue::from_static("{}"));
-        let tried = Context::try_from(headers);
+        let tried = Context::try_from((config, headers));
         assert!(tried.is_ok());
         assert!(tried.unwrap().client_context.is_some());
     }
 
     #[test]
     fn context_with_identity_resolves() {
+        let config = Arc::new(Config::default());
+
         let cognito_identity = CognitoIdentity {
             identity_id: String::new(),
             identity_pool_id: String::new(),
@@ -370,7 +390,7 @@ mod test {
             "lambda-runtime-cognito-identity",
             HeaderValue::from_str(&cognito_identity_str).unwrap(),
         );
-        let tried = Context::try_from(headers);
+        let tried = Context::try_from((config, headers));
         assert!(tried.is_ok());
         let tried = tried.unwrap();
         assert!(tried.identity.is_some());
@@ -379,6 +399,8 @@ mod test {
 
     #[test]
     fn context_with_bad_deadline_type_is_err() {
+        let config = Arc::new(Config::default());
+
         let mut headers = HeaderMap::new();
         headers.insert("lambda-runtime-aws-request-id", HeaderValue::from_static("my-id"));
         headers.insert(
@@ -390,86 +412,81 @@ mod test {
             HeaderValue::from_static("arn::myarn"),
         );
         headers.insert("lambda-runtime-trace-id", HeaderValue::from_static("arn::myarn"));
-        let tried = Context::try_from(headers);
+        let tried = Context::try_from((config, headers));
         assert!(tried.is_err());
     }
 
     #[test]
     fn context_with_bad_client_context_is_err() {
+        let config = Arc::new(Config::default());
+
         let mut headers = HeaderMap::new();
         headers.insert("lambda-runtime-aws-request-id", HeaderValue::from_static("my-id"));
         headers.insert("lambda-runtime-deadline-ms", HeaderValue::from_static("123"));
         headers.insert(
             "lambda-runtime-client-context",
             HeaderValue::from_static("BAD-Type,not JSON"),
         );
-        let tried = Context::try_from(headers);
+        let tried = Context::try_from((config, headers));
         assert!(tried.is_err());
     }
 
     #[test]
     fn context_with_empty_identity_is_err() {
+        let config = Arc::new(Config::default());
+
         let mut headers = HeaderMap::new();
         headers.insert("lambda-runtime-aws-request-id", HeaderValue::from_static("my-id"));
         headers.insert("lambda-runtime-deadline-ms", HeaderValue::from_static("123"));
         headers.insert("lambda-runtime-cognito-identity", HeaderValue::from_static("{}"));
-        let tried = Context::try_from(headers);
+        let tried = Context::try_from((config, headers));
         assert!(tried.is_err());
     }
 
     #[test]
     fn context_with_bad_identity_is_err() {
+        let config = Arc::new(Config::default());
+
         let mut headers = HeaderMap::new();
         headers.insert("lambda-runtime-aws-request-id", HeaderValue::from_static("my-id"));
         headers.insert("lambda-runtime-deadline-ms", HeaderValue::from_static("123"));
         headers.insert(
             "lambda-runtime-cognito-identity",
             HeaderValue::from_static("BAD-Type,not JSON"),
         );
-        let tried = Context::try_from(headers);
+        let tried = Context::try_from((config, headers));
         assert!(tried.is_err());
     }
 
     #[test]
     #[should_panic]
     #[allow(unused_must_use)]
     fn context_with_missing_request_id_should_panic() {
+        let config = Arc::new(Config::default());
+
         let mut headers = HeaderMap::new();
         headers.insert("lambda-runtime-aws-request-id", HeaderValue::from_static("my-id"));
         headers.insert(
             "lambda-runtime-invoked-function-arn",
             HeaderValue::from_static("arn::myarn"),
         );
         headers.insert("lambda-runtime-trace-id", HeaderValue::from_static("arn::myarn"));
-        Context::try_from(headers);
+        Context::try_from((config, headers));
     }
 
     #[test]
     #[should_panic]
     #[allow(unused_must_use)]
     fn context_with_missing_deadline_should_panic() {
+        let config = Arc::new(Config::default());
+
         let mut headers = HeaderMap::new();
         headers.insert("lambda-runtime-deadline-ms", HeaderValue::from_static("123"));
         headers.insert(
             "lambda-runtime-invoked-function-arn",
             HeaderValue::from_static("arn::myarn"),
         );
         headers.insert("lambda-runtime-trace-id", HeaderValue::from_static("arn::myarn"));
-        Context::try_from(headers);
-    }
-}
-
-impl Context {
-    /// Add environment details to the context by setting `env_config`.
-    pub fn with_config(self, config: &Config) -> Self {
-        Self {
-            env_config: config.clone(),
-            ..self
-        }
-    }
-
-    /// The execution deadline for the current invocation.
-    pub fn deadline(&self) -> SystemTime {
-        SystemTime::UNIX_EPOCH + Duration::from_millis(self.deadline)
+        Context::try_from((config, headers));
     }
 }