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software.amazon.awssdk.imds.internal.DefaultEc2MetadataClient Maven / Gradle / Ivy
/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
*/
package software.amazon.awssdk.imds.internal;
import static software.amazon.awssdk.imds.internal.RequestMarshaller.EC2_METADATA_TOKEN_TTL_HEADER;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.net.URI;
import java.time.Duration;
import java.time.Instant;
import java.util.Optional;
import java.util.concurrent.TimeUnit;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.Supplier;
import software.amazon.awssdk.annotations.Immutable;
import software.amazon.awssdk.annotations.SdkInternalApi;
import software.amazon.awssdk.annotations.ThreadSafe;
import software.amazon.awssdk.core.exception.RetryableException;
import software.amazon.awssdk.core.exception.SdkClientException;
import software.amazon.awssdk.core.internal.http.loader.DefaultSdkHttpClientBuilder;
import software.amazon.awssdk.core.retry.RetryPolicyContext;
import software.amazon.awssdk.http.AbortableInputStream;
import software.amazon.awssdk.http.HttpExecuteRequest;
import software.amazon.awssdk.http.HttpExecuteResponse;
import software.amazon.awssdk.http.HttpStatusFamily;
import software.amazon.awssdk.http.SdkHttpClient;
import software.amazon.awssdk.imds.Ec2MetadataClient;
import software.amazon.awssdk.imds.Ec2MetadataResponse;
import software.amazon.awssdk.imds.Ec2MetadataRetryPolicy;
import software.amazon.awssdk.imds.EndpointMode;
import software.amazon.awssdk.utils.Either;
import software.amazon.awssdk.utils.Logger;
import software.amazon.awssdk.utils.ToString;
import software.amazon.awssdk.utils.Validate;
import software.amazon.awssdk.utils.cache.CachedSupplier;
import software.amazon.awssdk.utils.cache.RefreshResult;
/**
* An Implementation of the Ec2Metadata Interface.
*/
@SdkInternalApi
@Immutable
@ThreadSafe
public final class DefaultEc2MetadataClient extends BaseEc2MetadataClient implements Ec2MetadataClient {
private static final Logger log = Logger.loggerFor(DefaultEc2MetadataClient.class);
private final SdkHttpClient httpClient;
private final Supplier tokenCache;
private final boolean httpClientIsInternal;
private DefaultEc2MetadataClient(Ec2MetadataBuilder builder) {
super(builder);
Validate.isTrue(builder.httpClient == null || builder.httpClientBuilder == null,
"The httpClient and the httpClientBuilder can't both be configured.");
this.httpClient = Either
.fromNullable(builder.httpClient, builder.httpClientBuilder)
.map(e -> e.map(Function.identity(), SdkHttpClient.Builder::build))
.orElseGet(() -> new DefaultSdkHttpClientBuilder().buildWithDefaults(IMDS_HTTP_DEFAULTS));
this.httpClientIsInternal = builder.httpClient == null;
this.tokenCache = CachedSupplier.builder(() -> RefreshResult.builder(this.getToken())
.staleTime(Instant.now().plus(tokenTtl))
.build())
.cachedValueName(toString())
.build();
}
@Override
public String toString() {
return ToString.create("Ec2MetadataClient");
}
@Override
public void close() {
if (httpClientIsInternal) {
httpClient.close();
}
}
public static Ec2MetadataBuilder builder() {
return new DefaultEc2MetadataClient.Ec2MetadataBuilder();
}
/**
* Gets the specified instance metadata value by the given path. Will retry base on the
* {@link Ec2MetadataRetryPolicy retry policy} provided, in the case of an IOException during request. Will not retry on
* SdkClientException, like 4XX HTTP error.
*
* @param path Input path of the resource to get.
* @return Instance metadata value as part of MetadataResponse Object
* @throws SdkClientException if the request for a token or the request for the Metadata does not have a 2XX SUCCESS response,
* if the maximum number of retries is reached, or if another IOException is thrown during the
* request.
*/
@Override
public Ec2MetadataResponse get(String path) {
Throwable lastCause = null;
// 3 retries means 4 total attempts
Token token = null;
for (int attempt = 0; attempt < retryPolicy.numRetries() + 1; attempt++) {
RetryPolicyContext retryPolicyContext = RetryPolicyContext.builder().retriesAttempted(attempt).build();
try {
if (token == null || token.isExpired()) {
token = tokenCache.get();
}
return sendRequest(path, token.value());
} catch (UncheckedIOException | RetryableException e) {
lastCause = e;
int currentTry = attempt;
log.debug(() -> "Error while executing EC2Metadata request, attempting retry. Current attempt: " + currentTry);
} catch (SdkClientException sdkClientException) {
int totalTries = attempt + 1;
log.debug(() -> String.format("Error while executing EC2Metadata request. Total attempts: %d. %s",
totalTries,
sdkClientException.getMessage()));
throw sdkClientException;
} catch (IOException ioe) {
lastCause = new UncheckedIOException(ioe);
int currentTry = attempt;
log.debug(() -> "Error while executing EC2Metadata request, attempting retry. Current attempt: " + currentTry);
}
pauseBeforeRetryIfNeeded(retryPolicyContext);
}
SdkClientException.Builder sdkClientExceptionBuilder = SdkClientException
.builder()
.message("Exceeded maximum number of retries. Total retry attempts: " + retryPolicy.numRetries());
if (lastCause != null) {
String msg = sdkClientExceptionBuilder.message();
sdkClientExceptionBuilder.cause(lastCause).message(msg);
}
throw sdkClientExceptionBuilder.build();
}
private Ec2MetadataResponse sendRequest(String path, String token) throws IOException {
HttpExecuteRequest httpExecuteRequest =
HttpExecuteRequest.builder()
.request(requestMarshaller.createDataRequest(path, token, tokenTtl))
.build();
HttpExecuteResponse response = httpClient.prepareRequest(httpExecuteRequest).call();
int statusCode = response.httpResponse().statusCode();
Optional responseBody = response.responseBody();
if (HttpStatusFamily.of(statusCode).isOneOf(HttpStatusFamily.SERVER_ERROR)) {
responseBody.map(BaseEc2MetadataClient::uncheckedInputStreamToUtf8)
.ifPresent(str -> log.debug(() -> "Metadata request response body: " + str));
throw RetryableException
.builder()
.message(String.format("The requested metadata at path '%s' returned Http code %s", path, statusCode))
.build();
}
if (!HttpStatusFamily.of(statusCode).isOneOf(HttpStatusFamily.SUCCESSFUL)) {
responseBody.map(BaseEc2MetadataClient::uncheckedInputStreamToUtf8)
.ifPresent(str -> log.debug(() -> "Metadata request response body: " + str));
throw SdkClientException
.builder()
.message(String.format("The requested metadata at path '%s' returned Http code %s", path, statusCode))
.build();
}
AbortableInputStream abortableInputStream = responseBody.orElseThrow(
SdkClientException.builder().message("Response body empty with Status Code " + statusCode)::build);
String data = uncheckedInputStreamToUtf8(abortableInputStream);
return Ec2MetadataResponse.create(data);
}
private void pauseBeforeRetryIfNeeded(RetryPolicyContext retryPolicyContext) {
long backoffTimeMillis = retryPolicy.backoffStrategy()
.computeDelayBeforeNextRetry(retryPolicyContext)
.toMillis();
if (backoffTimeMillis > 0) {
try {
TimeUnit.MILLISECONDS.sleep(backoffTimeMillis);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw SdkClientException.builder().message("Thread interrupted while trying to sleep").cause(e).build();
}
}
}
private Token getToken() {
HttpExecuteRequest httpExecuteRequest = HttpExecuteRequest.builder()
.request(requestMarshaller.createTokenRequest(tokenTtl))
.build();
HttpExecuteResponse response = null;
try {
response = httpClient.prepareRequest(httpExecuteRequest).call();
} catch (IOException e) {
throw new UncheckedIOException(e);
}
int statusCode = response.httpResponse().statusCode();
if (HttpStatusFamily.of(statusCode).isOneOf(HttpStatusFamily.SERVER_ERROR)) {
response.responseBody().map(BaseEc2MetadataClient::uncheckedInputStreamToUtf8)
.ifPresent(str -> log.debug(() -> "Metadata request response body: " + str));
throw RetryableException.builder()
.message("Could not retrieve token, " + statusCode + " error occurred").build();
}
if (!HttpStatusFamily.of(statusCode).isOneOf(HttpStatusFamily.SUCCESSFUL)) {
response.responseBody().map(BaseEc2MetadataClient::uncheckedInputStreamToUtf8)
.ifPresent(body -> log.debug(() -> "Token request response body: " + body));
throw SdkClientException.builder()
.message("Could not retrieve token, " + statusCode + " error occurred.")
.build();
}
String ttl = response.httpResponse()
.firstMatchingHeader(EC2_METADATA_TOKEN_TTL_HEADER)
.orElseThrow(() -> SdkClientException
.builder()
.message(EC2_METADATA_TOKEN_TTL_HEADER + " header not found in token response")
.build());
Duration ttlDuration;
try {
ttlDuration = Duration.ofSeconds(Long.parseLong(ttl));
} catch (NumberFormatException nfe) {
throw SdkClientException.create("Invalid token format received from IMDS server", nfe);
}
AbortableInputStream abortableInputStream = response.responseBody().orElseThrow(
SdkClientException.builder().message("Empty response body")::build);
String value = uncheckedInputStreamToUtf8(abortableInputStream);
return new Token(value, ttlDuration);
}
protected static final class Ec2MetadataBuilder implements Ec2MetadataClient.Builder {
private Ec2MetadataRetryPolicy retryPolicy;
private URI endpoint;
private Duration tokenTtl;
private EndpointMode endpointMode;
private SdkHttpClient httpClient;
private SdkHttpClient.Builder httpClientBuilder;
private Ec2MetadataBuilder() {
}
@Override
public Ec2MetadataBuilder retryPolicy(Ec2MetadataRetryPolicy retryPolicy) {
this.retryPolicy = retryPolicy;
return this;
}
@Override
public Builder retryPolicy(Consumer builderConsumer) {
Validate.notNull(builderConsumer, "builderConsumer must not be null");
Ec2MetadataRetryPolicy.Builder builder = Ec2MetadataRetryPolicy.builder();
builderConsumer.accept(builder);
return retryPolicy(builder.build());
}
@Override
public Ec2MetadataBuilder endpoint(URI endpoint) {
this.endpoint = endpoint;
return this;
}
@Override
public Ec2MetadataBuilder tokenTtl(Duration tokenTtl) {
this.tokenTtl = tokenTtl;
return this;
}
@Override
public Ec2MetadataBuilder endpointMode(EndpointMode endpointMode) {
this.endpointMode = endpointMode;
return this;
}
@Override
public Ec2MetadataBuilder httpClient(SdkHttpClient httpClient) {
this.httpClient = httpClient;
return this;
}
@Override
public Builder httpClient(SdkHttpClient.Builder builder) {
this.httpClientBuilder = builder;
return this;
}
public Ec2MetadataRetryPolicy getRetryPolicy() {
return this.retryPolicy;
}
public URI getEndpoint() {
return this.endpoint;
}
public Duration getTokenTtl() {
return this.tokenTtl;
}
public EndpointMode getEndpointMode() {
return this.endpointMode;
}
@Override
public Ec2MetadataClient build() {
return new DefaultEc2MetadataClient(this);
}
}
}
