Use environment for no_env example

rust_dev_preview/examples/sdk-config/src/bin/no_env.rs

@@ -2,20 +2,18 @@
  * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
  * SPDX-License-Identifier: Apache-2.0.
  */
-
 #![allow(clippy::result_large_err)]
 
+// File overview: This example shows how to create an SdkConfig without using the
+// default AWS environment configuration.
+
 use aws_config::meta::region::RegionProviderChain;
 use aws_credential_types::provider::{ProvideCredentials, SharedCredentialsProvider};
 use aws_sdk_s3::config::retry::RetryConfig;
 use aws_sdk_s3::config::Credentials;
 use aws_sdk_s3::{config::Region, meta::PKG_VERSION, Client, Error};
 use clap::Parser;
 
-// TODO(you): When running these examples, create or edit these files & update them with your values.
-const STATIC_ACCESS_KEY_ID: &str = include_str!("./testing/NO_ENV_STATIC_ACCESS_KEY_ID");
-const STATIC_SECRET_ACCESS_KEY: &str = include_str!("./testing/NO_ENV_STATIC_ACCESS_KEY_ID");
-
 #[derive(Debug, Parser)]
 struct Opt {
     /// The AWS Region.
@@ -41,26 +39,34 @@ async fn show_num_buckets(client: &Client) -> Result<(), Error> {
     Ok(())
 }
 
-// WARNING: This example is for demonstration purposes only. Your code should always
-// load credentials in a secure fashion.
+/// A Credentials provider that uses non-standard environment variables `MY_ID`
+/// and `MY_KEY` instead of `AWS_ACCESS_KEY_ID` and `AWS_SECRET_ACCESS_KEY`. This
+/// could alternatively load credentials from another secure source of environment
+/// secrets, if traditional AWS SDK for Rust credentials providers do not suit
+/// your use case.
+///
+/// WARNING: This example is for demonstration purposes only. Your code should always
+/// load credentials in a secure fashion.
 #[derive(Debug)]
 struct StaticCredentials {
-    access_key_id: &'static str,
-    secret_access_key: &'static str,
+    access_key_id: String,
+    secret_access_key: String,
 }
 
 impl StaticCredentials {
-    pub fn new(access_key_id: &'static str, secret_access_key: &'static str) -> Self {
+    pub fn new() -> Self {
+        let access_key_id = std::env::var("MY_ID").expect("access key id");
+        let secret_access_key = std::env::var("MY_KEY").expect("secret access key");
         Self {
-            access_key_id,
-            secret_access_key,
+            access_key_id: access_key_id.trim().to_string(),
+            secret_access_key: secret_access_key.trim().to_string(),
         }
     }
 
     async fn load_credentials(&self) -> aws_credential_types::provider::Result {
         Ok(Credentials::new(
-            self.access_key_id,
-            self.secret_access_key,
+            self.access_key_id.clone(),
+            self.secret_access_key.clone(),
             None,
             None,
             "StaticCredentials",
@@ -87,6 +93,11 @@ impl ProvideCredentials for StaticCredentials {
 ///   If the environment variable is not set, defaults to **us-west-2**.
 /// * `[-t TRIES]` - The number of times to (re)try the request.
 /// * `[-v]` - Whether to display additional information.
+///
+/// # Environment
+///
+/// * MY_ID - an AWS IAM Access Key ID to use for this request.
+/// * MY_KEY - an AWS IAM Secret Access Key to use for this request.
 #[tokio::main]
 async fn main() -> Result<(), Error> {
     tracing_subscriber::fmt::init();
@@ -115,10 +126,7 @@ async fn main() -> Result<(), Error> {
 
     let shared_config = aws_config::SdkConfig::builder()
         .region(region)
-        .credentials_provider(SharedCredentialsProvider::new(StaticCredentials::new(
-            STATIC_ACCESS_KEY_ID,
-            STATIC_SECRET_ACCESS_KEY,
-        )))
+        .credentials_provider(SharedCredentialsProvider::new(StaticCredentials::new()))
         // Set max attempts.
         // If tries is 1, there are no retries.
         .retry_config(RetryConfig::standard().with_max_attempts(tries))