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lauzadislauzadis
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Implement HostResolver using CRT
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3 files changed

+180
-1
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3 files changed

+180
-1
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‎aws-crt-kotlin/common/src/aws/sdk/kotlin/crt/InternalApi.kt‎

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/*
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* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
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* SPDX-License-Identifier: Apache-2.0
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*/
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package aws.sdk.kotlin.crt
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// Indicates this API is internal-only and should not be depended on
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public annotation class InternalApi

‎aws-crt-kotlin/native/src/aws/sdk/kotlin/crt/io/HostResolverNative.kt‎

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@@ -8,7 +8,10 @@ package aws.sdk.kotlin.crt.io
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import aws.sdk.kotlin.crt.*
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import aws.sdk.kotlin.crt.util.ShutdownChannel
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import aws.sdk.kotlin.crt.util.shutdownChannel
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import aws.sdk.kotlin.crt.util.toAwsString
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import aws.sdk.kotlin.crt.util.toKString
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import kotlinx.cinterop.*
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import kotlinx.coroutines.channels.Channel
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import libcrt.*
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@OptIn(ExperimentalForeignApi::class)
@@ -59,14 +62,101 @@ public actual class HostResolver private constructor(
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if (manageElg) elg.close()
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}
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public suspend fun resolve(hostname: String): List<CrtHostAddress> = memScoped {
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val awsHostname = hostname.toAwsString()
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val resultCallback = staticCFunction(::awsOnHostResolveFn)
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val channel: Channel<List<CrtHostAddress>> = Channel(Channel.RENDEZVOUS)
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val channelStableRef = StableRef.create(channel)
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val userData = channelStableRef.asCPointer()
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aws_host_resolver_resolve_host(ptr, awsHostname, resultCallback, aws_host_resolver_init_default_resolution_config(), userData)
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return channel.receive().also {
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aws_string_destroy(awsHostname)
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channelStableRef.dispose()
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}
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}
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}
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@OptIn(ExperimentalForeignApi::class)
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private fun onShutdownComplete(userData: COpaquePointer?) {
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if (userData == null) return
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if (userData == null) {
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return
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}
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val stableRef = userData.asStableRef<ShutdownChannel>()
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val ch = stableRef.get()
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ch.trySend(Unit)
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ch.close()
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stableRef.dispose()
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}
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// implementation of `aws_on_host_resolved_result_fn`: https://github.com/awslabs/aws-c-io/blob/db7a1bddc9a29eca18734d0af189c3924775dcf1/include/aws/io/host_resolver.h#L53C14-L53C44
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private fun awsOnHostResolveFn(
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hostResolver: CPointer<aws_host_resolver>?,
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hostName: CPointer<aws_string>?,
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errCode: Int,
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hostAddresses: CPointer<aws_array_list>?, // list of `aws_host_address`
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userData: COpaquePointer?,
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): Unit = memScoped {
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println("In callback awsOnHostResolveFn")
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if (errCode != AWS_OP_SUCCESS) {
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throw CrtRuntimeException("aws_on_host_resolved_result_fn", ec = errCode)
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}
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if (userData == null) {
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throw CrtRuntimeException("aws_on_host_resolved_result_fn: userData unexpectedly null")
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}
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val length = aws_array_list_length(hostAddresses)
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if (length == 0uL) {
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throw CrtRuntimeException("Failed to resolve host address for ${hostName?.toKString()}")
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}
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val result = ArrayList<CrtHostAddress>(length.toInt())
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val element = alloc<COpaquePointerVar>()
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for (i in 0uL until length) {
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awsAssertOpSuccess(
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aws_array_list_get_at_ptr(
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hostAddresses,
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element.ptr,
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i,
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),
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) { "aws_array_list_get_at_ptr failed at index $i" }
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val elemOpaque = element.value ?: throw CrtRuntimeException("aws_host_addresses value at index $i unexpectedly null")
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val addr = elemOpaque.reinterpret<aws_host_address>().pointed
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val hostStr = addr.host?.toKString() ?: throw CrtRuntimeException("aws_host_addresses `host` at index $i unexpectedly null")
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val addressStr = addr.address?.toKString() ?: throw CrtRuntimeException("aws_host_addresses `address` at index $i unexpectedly null")
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val addressType = when (addr.record_type) {
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aws_address_record_type.AWS_ADDRESS_RECORD_TYPE_A -> AddressType.IpV4
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aws_address_record_type.AWS_ADDRESS_RECORD_TYPE_AAAA -> AddressType.IpV6
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else -> throw CrtRuntimeException("received unsupported aws_host_address `aws_address_record_type`: ${addr.record_type}")
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}
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result += CrtHostAddress(host = hostStr, address = addressStr, addressType)
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}
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// Send results back through the channel
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val stableRef = userData.asStableRef<Channel<List<CrtHostAddress>>>()
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val channel = stableRef.get()
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channel.trySend(result)
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channel.close()
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}
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// Minimal wrapper of aws_host_address
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// https://github.com/awslabs/aws-c-io/blob/db7a1bddc9a29eca18734d0af189c3924775dcf1/include/aws/io/host_resolver.h#L31
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@InternalApi
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public data class CrtHostAddress(
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val host: String,
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val address: String,
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val addressType: AddressType,
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)
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@InternalApi
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public enum class AddressType {
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IpV4,
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IpV6,
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}

‎aws-crt-kotlin/native/test/aws/sdk/kotlin/crt/io/CrtHostResolverTest.kt‎

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/*
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* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
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* SPDX-License-Identifier: Apache-2.0
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*/
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package aws.sdk.kotlin.crt.io
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import kotlinx.coroutines.test.runTest
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import kotlin.test.Test
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import kotlin.test.assertEquals
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import kotlin.test.assertFails
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import kotlin.test.assertNotNull
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import kotlin.test.assertTrue
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// Copied from smithy-kotlin
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class CrtHostResolverTest {
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private val ipv4Regex = Regex("""^(\d{1,3}\.){3}\d{1,3}$""")
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private val ipv6Regex = Regex("""^(([0-9a-fA-F]{1,4}:){1,7}[0-9a-fA-F]{1,4}|([0-9a-fA-F]{1,4}:){1,7}:|::([0-9a-fA-F]{1,4}:){0,6}[0-9a-fA-F]{1,4})$""")
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@Test
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fun testResolveLocalhost() = runTest {
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val hr = HostResolver()
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val addresses = hr.resolve("localhost")
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assertTrue(addresses.isNotEmpty())
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addresses.forEach { addr ->
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assertEquals("localhost", addr.host)
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val localHostAddress = when (addr.addressType) {
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AddressType.IpV4 -> "127.0.0.1"
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AddressType.IpV6 -> "::1"
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}
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assertEquals(localHostAddress, addr.address)
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}
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}
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@Test
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fun testResolveIpv4Address() = runTest {
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val addresses = HostResolver().resolve("127.0.0.1")
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assertTrue(addresses.isNotEmpty())
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addresses.forEach { addr ->
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assertEquals(AddressType.IpV4, addr.addressType)
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assertEquals("127.0.0.1", addr.address)
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}
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}
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@Test
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fun testResolveIpv6Address() = runTest {
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val addresses = HostResolver().resolve("::1")
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assertTrue(addresses.isNotEmpty())
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addresses.forEach { addr ->
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assertEquals(AddressType.IpV6, addr.addressType)
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assertEquals("::1", addr.address)
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}
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}
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@Test
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fun testResolveExampleDomain() = runTest {
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val addresses = HostResolver().resolve("example.com")
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assertNotNull(addresses)
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assertTrue(addresses.isNotEmpty())
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addresses.forEach { addr ->
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assertEquals("example.com", addr.host)
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when (addr.addressType) {
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AddressType.IpV4 -> assertEquals(3, addr.address.count { it == '.' })
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AddressType.IpV6 -> assertEquals(if (addr.address.contains("::")) 6 else 7, addr.address.count { it == ':' })
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}
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}
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}
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@Test
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fun testResolveInvalidDomain() = runTest {
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assertFails {
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HostResolver().resolve("this-domain-definitely-does-not-exist-12345.local")
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}
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}
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}

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