feat(rt): AWS configuration loader and parser (#315)

Author: kggilmer

aws-runtime/auth/common/src/aws/sdk/kotlin/runtime/auth/signing/Presigner.kt

@@ -10,6 +10,7 @@ import aws.sdk.kotlin.crt.auth.signing.AwsSignedBodyHeaderType
 import aws.sdk.kotlin.crt.auth.signing.AwsSignedBodyValue
 import aws.sdk.kotlin.crt.auth.signing.AwsSigner
 import aws.sdk.kotlin.crt.auth.signing.AwsSigningConfig
+import aws.sdk.kotlin.runtime.InternalSdkApi
 import aws.sdk.kotlin.runtime.auth.credentials.CredentialsProvider
 import aws.sdk.kotlin.runtime.auth.credentials.toCrt
 import aws.sdk.kotlin.runtime.crt.path
@@ -24,7 +25,6 @@ import aws.smithy.kotlin.runtime.http.Protocol
 import aws.smithy.kotlin.runtime.http.QueryParameters
 import aws.smithy.kotlin.runtime.http.Url
 import aws.smithy.kotlin.runtime.http.request.HttpRequest
-import aws.smithy.kotlin.runtime.util.InternalApi
 import aws.sdk.kotlin.crt.http.HttpRequest as CrtHttpRequest
 
 /**
@@ -80,7 +80,7 @@ public data class PresignedRequestConfig(
  * @param requestConfig The presign configuration to use in signing the request
  * @return a [HttpRequest] that can be executed by any HTTP client within the specified duration.
  */
-@InternalApi
+@InternalSdkApi
 public suspend fun createPresignedRequest(serviceConfig: ServicePresignConfig, requestConfig: PresignedRequestConfig): HttpRequest {
     val crtCredentials = serviceConfig.credentialsProvider.getCredentials().toCrt()
     val endpoint = serviceConfig.endpointResolver.resolve(serviceConfig.serviceId, serviceConfig.region)

aws-runtime/aws-core/build.gradle.kts

@@ -15,6 +15,16 @@ kotlin {
         commonMain {
             dependencies {
                 api("aws.smithy.kotlin:runtime-core:$smithyKotlinVersion")
+                implementation("aws.smithy.kotlin:logging:$smithyKotlinVersion")
+            }
+        }
+        commonTest {
+            dependencies {
+                val kotlinxSerializationVersion: String by project
+                val mockkVersion: String by project
+                implementation("org.jetbrains.kotlinx:kotlinx-serialization-runtime:$kotlinxSerializationVersion")
+                implementation("io.mockk:mockk:$mockkVersion")
+                implementation(project(":aws-runtime:testing"))
             }
         }
     }

aws-runtime/aws-core/common/src/aws/sdk/kotlin/runtime/Annotations.kt

@@ -16,7 +16,7 @@ package aws.sdk.kotlin.runtime
 @Suppress("DEPRECATION")
 @RequiresOptIn(
     level = RequiresOptIn.Level.ERROR,
-    message = "This API is internal to aws-client-rt and generated SDK's and should not be used. It could be removed or changed without notice."
+    message = "This API is internal to aws-runtime and generated SDKs and should not be used. It could be removed or changed without notice."
 )
 @Experimental(level = Experimental.Level.ERROR)
 @Target(

aws-runtime/aws-core/common/src/aws/sdk/kotlin/runtime/AwsSdkSetting.kt

@@ -5,14 +5,17 @@
 
 package aws.sdk.kotlin.runtime
 
+import aws.smithy.kotlin.runtime.util.Platform
+
 // NOTE: The JVM property names MUST match the ones defined in the Java SDK for any setting added.
 // see: https://github.com/aws/aws-sdk-java-v2/blob/master/core/sdk-core/src/main/java/software/amazon/awssdk/core/SdkSystemSetting.java
+// see: https://github.com/aws/aws-sdk-java-v2/blob/master/docs/LaunchChangelog.md#61-environment-variables-and-system-properties
 
 /**
  * Settings to configure SDK runtime behavior
  */
 @InternalSdkApi
-public sealed class AwsSdkSetting<T> (
+public sealed class AwsSdkSetting<T>(
     /**
      * The name of the corresponding environment variable that configures the setting
      */
@@ -52,6 +55,17 @@ public sealed class AwsSdkSetting<T> (
      */
     public object AwsRegion : AwsSdkSetting<String>("AWS_REGION", "aws.region")
 
+    /**
+     * Configure the default path to the shared config file.
+     */
+    public object AwsConfigFile : AwsSdkSetting<String>("AWS_CONFIG_FILE", "aws.configFile")
+
+    /**
+     * Configure the default path to the shared credentials profile file.
+     */
+    public object AwsSharedCredentialsFile :
+        AwsSdkSetting<String>("AWS_SHARED_CREDENTIALS_FILE", "aws.sharedCredentialsFile")
+
     /**
      * The execution environment of the SDK user. This is automatically set in certain environments by the underlying AWS service.
      * For example, AWS Lambda will automatically specify a runtime indicating that the SDK is being used within Lambda.
@@ -63,3 +77,14 @@ public sealed class AwsSdkSetting<T> (
      */
     public object AwsProfile : AwsSdkSetting<String>("AWS_PROFILE", "aws.profile", "default")
 }
+
+/**
+ * Read the [AwsSdkSetting] by first checking JVM property, environment variable, and default value.
+ * Property sources not available on a given platform will be ignored.
+ *
+ * @param platform A singleton that provides platform-specific settings.  Exposed as a parameter for testing.
+ * @return the value of the [AwsSdkSetting] or null if undefined.
+ */
+@InternalSdkApi
+public inline fun <reified T> AwsSdkSetting<T>.resolve(platform: Platform): T? =
+    (platform.getProperty(jvmProperty) ?: platform.getenv(environmentVariable) ?: defaultValue) as T?

aws-runtime/aws-core/common/src/aws/sdk/kotlin/runtime/config/AwsConfigLoader.kt

@@ -0,0 +1,115 @@
+package aws.sdk.kotlin.runtime.config
+
+import aws.sdk.kotlin.runtime.AwsSdkSetting
+import aws.sdk.kotlin.runtime.InternalSdkApi
+import aws.sdk.kotlin.runtime.resolve
+import aws.smithy.kotlin.runtime.util.OsFamily
+import aws.smithy.kotlin.runtime.util.Platform
+
+/**
+ * Load the properties of the specified or default AWS configuration profile.  This
+ * function will return the properties of the profile specified by the local environment
+ * or the default profile if none is defined.
+ *
+ * This function performs no caching. File I/O will be performed with each call.
+ *
+ * @param platform used for unit testing
+ *
+ * @return an [AwsProfile] regardless if local configuration files are available
+ */
+@InternalSdkApi
+public suspend fun loadActiveAwsProfile(platform: Platform): AwsProfile {
+    // Determine active profile and location of configuration files
+    val source = resolveConfigSource(platform)
+
+    // Read all profiles from local system
+    val allProfiles = loadAwsProfiles(platform, source)
+
+    // Return the active profile
+    return AwsProfile(source.profile, allProfiles[source.profile] ?: emptyMap())
+}
+
+/**
+ * Load all profiles specified in local configuration files.
+ *
+ * @param platform Platform from which to resolve configuration data
+ * @param source Specifies the location of the configuration files
+ *
+ * @return A map of all profiles, which each are a map of key/value pairs.
+ */
+private suspend fun loadAwsProfiles(platform: Platform, source: AwsConfigurationSource): Map<String, Map<String, String>> {
+
+    // merged AWS configuration based on optional configuration and credential file contents
+    return mergeProfiles(
+        parse(FileType.CONFIGURATION, platform.readFileOrNull(source.configPath)?.decodeToString()),
+        parse(FileType.CREDENTIAL, platform.readFileOrNull(source.credentialsPath)?.decodeToString()),
+    )
+}
+
+// Merge contents of profile maps
+internal fun mergeProfiles(vararg maps: ProfileMap) = buildMap<String, Map<String, String>> {
+    maps.forEach { map ->
+        map.entries.forEach { entry ->
+            put(entry.key, (get(entry.key) ?: emptyMap()) + entry.value)
+        }
+    }
+}
+
+// Specifies the active profile and configured (may not actually exist) locations of configuration files.
+internal data class AwsConfigurationSource(val profile: String, val configPath: String, val credentialsPath: String)
+
+/**
+ * Determine the source of AWS configuration
+ */
+internal fun resolveConfigSource(platform: Platform) =
+    AwsConfigurationSource(
+        // If the user does not specify the profile to be used, the default profile must be used by the SDK.
+        // The default profile must be overridable using the AWS_PROFILE environment variable.
+        AwsSdkSetting.AwsProfile.resolve(platform) ?: Literals.DEFAULT_PROFILE,
+        normalizePath(FileType.CONFIGURATION.path(platform), platform),
+        normalizePath(FileType.CREDENTIAL.path(platform), platform)
+    )
+
+/**
+ * Expands paths prefixed with '~' to the home directory under which the SDK is running.
+ *
+ * User Home Resolution: The user's home directory must be resolved when the file location starts with ~/ or ~
+ * followed by the operating system's default path separator by checking the following variables, in order:
+ *
+ * 1. (All Platforms) The HOME environment variable.
+ * 2. (Windows Platforms) The USERPROFILE environment variable.
+ * 3. (Windows Platforms) The HOMEDRIVE environment variable prepended to the HOMEPATH environment variable (ie. $HOMEDRIVE$HOMEPATH).
+ * 4. (Optional) A language-specific home path resolution function or variable.
+ */
+internal fun normalizePath(path: String, platform: Platform): String {
+    if (!path.trim().startsWith('~')) return path
+
+    val home = resolveHomeDir(platform) ?: error("Unable to determine user home directory")
+
+    return home + path.substring(1)
+}
+
+/**
+ * Load the user's home directory based on the priorities:
+ *
+ * If the implementation cannot determine the customer's platform, the USERPROFILE and HOMEDRIVE + HOMEPATH environment
+ * variables must be checked for all platforms. If the implementation can determine the customer's platform, the
+ * USERPROFILE and HOMEDRIVE + HOMEPATH environment variables must not be checked on non-windows platforms.
+ *
+ * @param
+ * @return the absolute path of the home directory from which the SDK is running, or null if unspecified by environment.
+ */
+private fun resolveHomeDir(platform: Platform): String? =
+    with(platform) {
+        when (osInfo().family) {
+            OsFamily.Unknown,
+            OsFamily.Windows ->
+                getenv("HOME")
+                    ?: getenv("USERPROFILE")
+                    ?: (getenv("HOMEDRIVE") to getenv("HOMEPATH")).concatOrNull()
+                    ?: getProperty("user.home")
+            else ->
+                getenv("HOME")
+                    ?: getProperty("user.home")
+        }
+    }