feat: add AuthTokenGenerator (#1212)

Author: lauzadis

runtime/auth/aws-signing-common/api/aws-signing-common.api

@@ -1,3 +1,13 @@
+public final class aws/smithy/kotlin/runtime/auth/awssigning/AuthTokenGenerator {
+	public fun <init> (Ljava/lang/String;Laws/smithy/kotlin/runtime/auth/awscredentials/CredentialsProvider;Laws/smithy/kotlin/runtime/auth/awssigning/AwsSigner;Laws/smithy/kotlin/runtime/time/Clock;)V
+	public synthetic fun <init> (Ljava/lang/String;Laws/smithy/kotlin/runtime/auth/awscredentials/CredentialsProvider;Laws/smithy/kotlin/runtime/auth/awssigning/AwsSigner;Laws/smithy/kotlin/runtime/time/Clock;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public final fun generateAuthToken-exY8QGI (Laws/smithy/kotlin/runtime/net/url/Url;Ljava/lang/String;JLkotlin/coroutines/Continuation;)Ljava/lang/Object;
+	public final fun getClock ()Laws/smithy/kotlin/runtime/time/Clock;
+	public final fun getCredentialsProvider ()Laws/smithy/kotlin/runtime/auth/awscredentials/CredentialsProvider;
+	public final fun getService ()Ljava/lang/String;
+	public final fun getSigner ()Laws/smithy/kotlin/runtime/auth/awssigning/AwsSigner;
+}
+
 public final class aws/smithy/kotlin/runtime/auth/awssigning/AwsChunkedByteReadChannel : aws/smithy/kotlin/runtime/io/SdkByteReadChannel {
 	public fun <init> (Laws/smithy/kotlin/runtime/io/SdkByteReadChannel;Laws/smithy/kotlin/runtime/auth/awssigning/AwsSigner;Laws/smithy/kotlin/runtime/auth/awssigning/AwsSigningConfig;[BLaws/smithy/kotlin/runtime/http/DeferredHeaders;)V
 	public synthetic fun <init> (Laws/smithy/kotlin/runtime/io/SdkByteReadChannel;Laws/smithy/kotlin/runtime/auth/awssigning/AwsSigner;Laws/smithy/kotlin/runtime/auth/awssigning/AwsSigningConfig;[BLaws/smithy/kotlin/runtime/http/DeferredHeaders;ILkotlin/jvm/internal/DefaultConstructorMarker;)V

runtime/auth/aws-signing-common/common/src/aws/smithy/kotlin/runtime/auth/awssigning/AuthTokenGenerator.kt

@@ -0,0 +1,44 @@
+/*
+* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+* SPDX-License-Identifier: Apache-2.0
+*/
+package aws.smithy.kotlin.runtime.auth.awssigning
+
+import aws.smithy.kotlin.runtime.auth.awscredentials.CredentialsProvider
+import aws.smithy.kotlin.runtime.auth.awssigning.AwsSigningConfig.Companion.invoke
+import aws.smithy.kotlin.runtime.http.HttpMethod
+import aws.smithy.kotlin.runtime.http.request.HttpRequest
+import aws.smithy.kotlin.runtime.net.url.Url
+import aws.smithy.kotlin.runtime.time.Clock
+import kotlin.time.Duration
+
+/**
+ * Generates an authentication token, which is a SigV4-signed URL with the HTTP scheme removed.
+ * @param service The name of the service the token is being generated for
+ * @param credentialsProvider The [CredentialsProvider] which will provide credentials to use when generating the auth token
+ * @param signer The [AwsSigner] implementation to use when creating the authentication token
+ * @param clock The [Clock] implementation to use
+ */
+public class AuthTokenGenerator(
+    public val service: String,
+    public val credentialsProvider: CredentialsProvider,
+    public val signer: AwsSigner,
+    public val clock: Clock = Clock.System,
+) {
+    private fun Url.trimScheme(): String = toString().removePrefix(scheme.protocolName).removePrefix("://")
+
+    public suspend fun generateAuthToken(endpoint: Url, region: String, expiration: Duration): String {
+        val req = HttpRequest(HttpMethod.GET, endpoint)
+
+        val config = AwsSigningConfig {
+            credentials = credentialsProvider.resolve()
+            this.region = region
+            service = this@AuthTokenGenerator.service
+            signingDate = clock.now()
+            expiresAfter = expiration
+            signatureType = AwsSignatureType.HTTP_REQUEST_VIA_QUERY_PARAMS
+        }
+
+        return signer.sign(req, config).output.url.trimScheme()
+    }
+}

runtime/auth/aws-signing-common/common/test/aws/smithy/kotlin/runtime/auth/awssigning/AuthTokenGeneratorTest.kt

@@ -0,0 +1,71 @@
+/*
+* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+* SPDX-License-Identifier: Apache-2.0
+*/
+package aws.smithy.kotlin.runtime.auth.awssigning
+
+import aws.smithy.kotlin.runtime.auth.awscredentials.Credentials
+import aws.smithy.kotlin.runtime.auth.awscredentials.CredentialsProvider
+import aws.smithy.kotlin.runtime.collections.Attributes
+import aws.smithy.kotlin.runtime.http.Headers
+import aws.smithy.kotlin.runtime.http.request.HttpRequest
+import aws.smithy.kotlin.runtime.http.request.toBuilder
+import aws.smithy.kotlin.runtime.net.Host
+import aws.smithy.kotlin.runtime.net.url.Url
+import aws.smithy.kotlin.runtime.time.Instant
+import aws.smithy.kotlin.runtime.time.ManualClock
+import kotlinx.coroutines.test.runTest
+import kotlin.test.Test
+import kotlin.test.assertContains
+import kotlin.test.assertTrue
+import kotlin.time.Duration.Companion.seconds
+import kotlin.time.DurationUnit
+
+class AuthTokenGeneratorTest {
+    @Test
+    fun testGenerateAuthToken() = runTest {
+        val credentials = Credentials("akid", "secret")
+
+        val credentialsProvider = object : CredentialsProvider {
+            var credentialsResolved = false
+            override suspend fun resolve(attributes: Attributes): Credentials {
+                credentialsResolved = true
+                return credentials
+            }
+        }
+
+        val clock = ManualClock(Instant.fromEpochSeconds(0))
+
+        val generator = AuthTokenGenerator("foo", credentialsProvider, TEST_SIGNER, clock = clock)
+
+        val endpoint = Url { host = Host.parse("foo.bar.us-east-1.baz") }
+        val token = generator.generateAuthToken(endpoint, "us-east-1", 333.seconds)
+
+        assertContains(token, "foo.bar.us-east-1.baz")
+        assertContains(token, "X-Amz-Credential=signature") // test custom signer was invoked
+        assertContains(token, "X-Amz-Expires=333") // expiration
+        assertContains(token, "X-Amz-SigningDate=0") // clock
+
+        assertTrue(credentialsProvider.credentialsResolved)
+    }
+}
+
+private val TEST_SIGNER = object : AwsSigner {
+    override suspend fun sign(
+        request: HttpRequest,
+        config: AwsSigningConfig,
+    ): AwsSigningResult<HttpRequest> {
+        val builder = request.toBuilder()
+        builder.url.parameters.decodedParameters.apply {
+            put("X-Amz-Credential", "signature")
+            put("X-Amz-Expires", (config.expiresAfter?.toLong(DurationUnit.SECONDS) ?: 900).toString())
+            put("X-Amz-SigningDate", config.signingDate.epochSeconds.toString())
+        }
+
+        return AwsSigningResult<HttpRequest>(builder.build(), "signature".encodeToByteArray())
+    }
+
+    override suspend fun signChunk(chunkBody: ByteArray, prevSignature: ByteArray, config: AwsSigningConfig): AwsSigningResult<Unit> = throw IllegalStateException("signChunk unexpectedly invoked")
+
+    override suspend fun signChunkTrailer(trailingHeaders: Headers, prevSignature: ByteArray, config: AwsSigningConfig): AwsSigningResult<Unit> = throw IllegalStateException("signChunkTrailer unexpectedly invoked")
+}