Make credentials accessible via Environment::credentials()

Author: thekid

src/main/php/com/amazon/aws/lambda/Environment.class.php

@@ -10,6 +10,7 @@
  * Runtime environment of a lambda
  *
  * @test  com.amazon.aws.lambda.unittest.EnvironmentTest
+ * @see   https://docs.aws.amazon.com/lambda/latest/dg/configuration-envvars.html
  */
 class Environment {
   public $root, $variables, $writer, $properties;
@@ -46,6 +47,19 @@ public function variable($name) {
     return $this->variables[$name] ?? null;
   }
 
+  /**
+   * Returns credentials from this environment
+   *
+   * @return com.amazon.aws.lambda.Credentials
+   */
+  public function credentials() {
+    return new Credentials(
+      $this->variables['AWS_ACCESS_KEY_ID'],
+      $this->variables['AWS_SECRET_ACCESS_KEY'],
+      $this->variables['AWS_SESSION_TOKEN'] ?? null,
+    );
+  }
+
   /**
    * Writes a trace message
    *

src/test/php/com/amazon/aws/lambda/unittest/EnvironmentTest.class.php

@@ -1,6 +1,6 @@
 <?php namespace com\amazon\aws\lambda\unittest;
 
-use com\amazon\aws\lambda\Environment;
+use com\amazon\aws\lambda\{Environment, Credentials};
 use io\streams\{MemoryOutputStream, StringWriter};
 use io\{File, Files, Path};
 use lang\ElementNotFoundException;
@@ -45,6 +45,33 @@ public function non_existant_variable() {
     Assert::null((new Environment('.', null, []))->variable('TEST'));
   }
 
+  #[Test]
+  public function credentials() {
+    $env= [
+      'AWS_ACCESS_KEY_ID'     => 'KEY',
+      'AWS_SECRET_ACCESS_KEY' => 'SECRET',
+    ];
+
+    Assert::equals(
+      new Credentials('KEY', 'SECRET'),
+      (new Environment('.', null, $env))->credentials()
+    );
+  }
+
+  #[Test]
+  public function credentials_with_session() {
+    $env= [
+      'AWS_ACCESS_KEY_ID'     => 'KEY',
+      'AWS_SECRET_ACCESS_KEY' => 'SECRET',
+      'AWS_SESSION_TOKEN'     => 'SESSION',
+    ];
+
+    Assert::equals(
+      new Credentials('KEY', 'SECRET', 'SESSION'),
+      (new Environment('.', null, $env))->credentials()
+    );
+  }
+
   #[Test]
   public function trace() {
     $stream= new MemoryOutputStream();