feat: add support for bedrock api key auth

codegen/smithy-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/core/RuntimeTypes.kt

@@ -374,6 +374,8 @@ object RuntimeTypes {
             val BearerTokenAuthScheme = symbol("BearerTokenAuthScheme")
             val BearerTokenProviderConfig = symbol("BearerTokenProviderConfig")
             val BearerTokenProvider = symbol("BearerTokenProvider")
+            val BearerToken = symbol("BearerToken")
+            val EnvironmentBearerTokenProvider = symbol("EnvironmentBearerTokenProvider")
 
             val reprioritizeAuthOptions = symbol("reprioritizeAuthOptions")
         }

runtime/auth/http-auth/api/http-auth.api

@@ -59,6 +59,12 @@ public final class aws/smithy/kotlin/runtime/http/auth/BearerTokenSigner : aws/s
 public abstract interface class aws/smithy/kotlin/runtime/http/auth/CloseableBearerTokenProvider : aws/smithy/kotlin/runtime/http/auth/BearerTokenProvider, java/io/Closeable {
 }
 
+public final class aws/smithy/kotlin/runtime/http/auth/EnvironmentBearerTokenProvider : aws/smithy/kotlin/runtime/http/auth/BearerTokenProvider {
+	public fun <init> (Ljava/lang/String;Laws/smithy/kotlin/runtime/util/PlatformProvider;)V
+	public synthetic fun <init> (Ljava/lang/String;Laws/smithy/kotlin/runtime/util/PlatformProvider;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun resolve (Laws/smithy/kotlin/runtime/collections/Attributes;Lkotlin/coroutines/Continuation;)Ljava/lang/Object;
+}
+
 public final class aws/smithy/kotlin/runtime/http/auth/ReprioritizeAuthOptionsKt {
 	public static final fun reprioritizeAuthOptions (Ljava/util/List;Ljava/util/List;)Ljava/util/List;
 }

runtime/auth/http-auth/common/src/aws/smithy/kotlin/runtime/http/auth/EnvironmentBearerTokenProvider.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package aws.smithy.kotlin.runtime.http.auth
+
+import aws.smithy.kotlin.runtime.collections.Attributes
+import aws.smithy.kotlin.runtime.collections.emptyAttributes
+import aws.smithy.kotlin.runtime.time.Instant
+import aws.smithy.kotlin.runtime.util.PlatformProvider
+
+/**
+ * A [BearerTokenProvider] that extracts the bearer token from the target environment variable.
+ */
+public class EnvironmentBearerTokenProvider(
+    private val key: String,
+    private val platform: PlatformProvider = PlatformProvider.System,
+) : BearerTokenProvider {
+    override suspend fun resolve(attributes: Attributes): BearerToken {
+        val bearerToken = platform.getenv(key)
+            ?: error("$key environment variable is not set")
+
+        return object : BearerToken {
+            override val token: String = bearerToken
+            override val attributes: Attributes = emptyAttributes()
+            override val expiration: Instant? = null
+        }
+    }
+}

runtime/auth/http-auth/common/test/aws/smithy/kotlin/runtime/http/auth/EnvironmentBearerTokenProviderTest.kt

@@ -0,0 +1,35 @@
+package aws.smithy.kotlin.runtime.http.auth
+
+import aws.smithy.kotlin.runtime.collections.emptyAttributes
+import aws.smithy.kotlin.runtime.util.TestPlatformProvider
+import kotlinx.coroutines.test.runTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
+
+class EnvironmentBearerTokenProviderTest {
+    @Test
+    fun testResolveWithValidToken() = runTest {
+        val provider = EnvironmentBearerTokenProvider(
+            "TEST_TOKEN",
+            TestPlatformProvider(mutableMapOf("TEST_TOKEN" to "test-bearer-token")),
+        )
+
+        val token = provider.resolve()
+
+        assertEquals("test-bearer-token", token.token)
+    }
+
+    @Test
+    fun testResolveWithMissingToken() = runTest {
+        val provider = EnvironmentBearerTokenProvider(
+            "MISSING_TEST_TOKEN",
+            TestPlatformProvider(mutableMapOf()),
+        )
+
+        val exception = assertFailsWith<IllegalStateException> {
+            provider.resolve(emptyAttributes())
+        }
+        assertEquals("MISSING_TEST_TOKEN environment variable is not set", exception.message)
+    }
+}