org.zalando.boot.etcd.EtcdClient Maven / Gradle / Ivy
/*
* Copyright 2015 Zalando SE
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License 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 org.zalando.boot.etcd;
import java.io.IOException;
import java.net.URI;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.http.HttpMethod;
import org.springframework.http.RequestEntity;
import org.springframework.http.ResponseEntity;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.http.converter.support.AllEncompassingFormHttpMessageConverter;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.client.HttpStatusCodeException;
import org.springframework.web.client.ResourceAccessException;
import org.springframework.web.client.RestClientException;
import org.springframework.web.client.RestTemplate;
import org.springframework.web.util.UriComponentsBuilder;
import lombok.Getter;
import lombok.Setter;
import lombok.extern.apachecommons.CommonsLog;
/**
* A service that encapsulates the communication with an etcd cluster.
*
* @see https://coreos.com
* /etcd/docs/2.1.0/api.html
*/
@CommonsLog
public class EtcdClient implements InitializingBean, DisposableBean {
/**
* base path
*/
private static final String BASE_PATH = "{location}/v2";
/**
* key space containing all nodes with key-value pairs
*/
private static final String KEYSPACE = BASE_PATH + "/keys";
/**
* member space
*/
private static final String MEMBERSPACE = BASE_PATH + "/members";
/**
* request converter
*/
private AllEncompassingFormHttpMessageConverter requestConverter = new AllEncompassingFormHttpMessageConverter();
/**
* response converter
*/
private MappingJackson2HttpMessageConverter responseConverter = new MappingJackson2HttpMessageConverter();
/**
* request factory
*/
@Getter
@Setter
private ClientHttpRequestFactory requestFactory;
/**
* template.
*/
private RestTemplate template;
/**
* number of retries
*/
@Getter
@Setter
private int retryCount = 0;
/**
* duration of retries
*/
@Getter
@Setter
private int retryDuration = 0;
/**
* locations
*/
private String[] locations;
/**
* indicates whether the location updater is enabled
*/
private boolean locationUpdaterEnabled = true;
/**
* current location
*/
private int locationIndex = 0;
/**
* location updater
*/
private ScheduledExecutorService locationUpdater = Executors.newScheduledThreadPool(1, new ThreadFactory() {
@Override
public Thread newThread(Runnable r) {
Thread t = new Thread(r, "etcd-location-updater");
t.setDaemon(true);
return t;
}
});
/**
* Creates a new EtcdClient.
*/
public EtcdClient() {
super();
}
/**
* Creates a new EtcdClient with the given location.
*
* @param location
* the location
*/
public EtcdClient(String location) {
this.locations = new String[] { location };
}
/**
* Creates a new EtcdClient with the given locations.
*
* @param locations
* the locations
*/
public EtcdClient(String[] locations) {
this.locations = locations;
}
public boolean isLocationUpdaterEnabled() {
return locationUpdaterEnabled;
}
public void setLocationUpdaterEnabled(boolean value) {
this.locationUpdaterEnabled = value;
}
/**
* @param value
* the locations
*/
public void setLocations(String[] value) {
this.locations = value == null ? new String[0] : value;
}
/**
* @return the locations
*/
public String[] getLocations() {
return locations;
}
/**
* @return the current location
*/
protected String getCurrentLocation() {
return locations[locationIndex];
}
/**
* Returns the node with the given key from etcd.
*
* @param key
* the node's key
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse get(String key) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
return execute(builder, HttpMethod.GET, null, EtcdResponse.class);
}
/**
* Returns the node with the given key from etcd.
*
* @param key
* the node's key
* @param recursive
* true if child nodes should be returned,
* false otherwise
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse get(String key, boolean recursive) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
builder.queryParam("recursive", recursive);
return execute(builder, HttpMethod.GET, null, EtcdResponse.class);
}
/**
* Sets the value of the node with the given key in etcd. Any previously
* existing key-value pair is returned as prevNode in the etcd response.
*
* @param key
* the node's key
* @param value
* the node's value
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse put(final String key, final String value) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
MultiValueMap payload = new LinkedMultiValueMap<>(1);
payload.set("value", value);
return execute(builder, HttpMethod.PUT, payload, EtcdResponse.class);
}
/**
* Sets the value of the node with the given key in etcd.
*
* @param key
* the node's key
* @param value
* the node's value
* @param ttl
* the node's time-to-live or -1 to unset existing
* ttl
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse put(String key, String value, int ttl) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
builder.queryParam("ttl", ttl == -1 ? "" : ttl);
MultiValueMap payload = new LinkedMultiValueMap<>(1);
payload.set("value", value);
return execute(builder, HttpMethod.PUT, payload, EtcdResponse.class);
}
/**
* Deletes the node with the given key from etcd.
*
* @param key
* the node's key
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse delete(final String key) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
return execute(builder, HttpMethod.DELETE, null, EtcdResponse.class);
}
/**
* Creates a new node with the given key-value pair under the node with the
* given key.
*
* @param key
* the directory node's key
* @param value
* the value of the created node
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse create(final String key, final String value) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
MultiValueMap payload = new LinkedMultiValueMap<>(1);
payload.set("value", value);
return execute(builder, HttpMethod.POST, payload, EtcdResponse.class);
}
/**
* Atomically creates or updates a key-value pair in etcd.
*
* @param key
* the key
* @param value
* the value
* @param prevExist
* true if the existing node should be updated,
* false of the node should be created
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse compareAndSwap(final String key, final String value, boolean prevExist) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
builder.queryParam("prevExist", prevExist);
MultiValueMap payload = new LinkedMultiValueMap<>(1);
payload.set("value", value);
return execute(builder, HttpMethod.PUT, payload, EtcdResponse.class);
}
/**
* Atomically creates or updates a key-value pair in etcd.
*
* @param key
* the key
* @param value
* the value
* @param ttl
* the time-to-live
* @param prevExist
* true if the existing node should be updated,
* false of the node should be created
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse compareAndSwap(final String key, final String value, int ttl, boolean prevExist)
throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
builder.queryParam("ttl", ttl == -1 ? "" : ttl);
builder.queryParam("prevExist", prevExist);
MultiValueMap payload = new LinkedMultiValueMap<>(1);
payload.set("value", value);
return execute(builder, HttpMethod.PUT, payload, EtcdResponse.class);
}
/**
* Atomically updates a key-value pair in etcd.
*
* @param key
* the key
* @param value
* the value
* @param prevIndex
* the modified index of the key
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse compareAndSwap(String key, String value, int prevIndex) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
builder.queryParam("prevIndex", prevIndex);
MultiValueMap payload = new LinkedMultiValueMap<>(1);
payload.set("value", value);
return execute(builder, HttpMethod.PUT, payload, EtcdResponse.class);
}
/**
* Atomically updates a key-value pair in etcd.
*
* @param key
* the key
* @param value
* the value
* @param ttl
* the time-to-live
* @param prevIndex
* the modified index of the key
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse compareAndSwap(String key, String value, int ttl, int prevIndex) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
builder.queryParam("ttl", ttl == -1 ? "" : ttl);
builder.queryParam("prevIndex", prevIndex);
MultiValueMap payload = new LinkedMultiValueMap<>(1);
payload.set("value", value);
return execute(builder, HttpMethod.PUT, payload, EtcdResponse.class);
}
/**
* Atomically updates a key-value pair in etcd.
*
* @param key
* the key
* @param value
* the value
* @param prevValue
* the previous value of the key
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse compareAndSwap(String key, String value, String prevValue) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
builder.queryParam("prevValue", prevValue);
MultiValueMap payload = new LinkedMultiValueMap<>(1);
payload.set("value", value);
return execute(builder, HttpMethod.PUT, payload, EtcdResponse.class);
}
/**
* Atomically updates a key-value pair in etcd.
*
* @param key
* the key
* @param value
* the value
* @param ttl
* the time-to-live
* @param prevValue
* the previous value of the key
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse compareAndSwap(String key, String value, int ttl, String prevValue) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
builder.queryParam("ttl", ttl == -1 ? "" : ttl);
builder.queryParam("prevValue", prevValue);
MultiValueMap payload = new LinkedMultiValueMap<>(1);
payload.set("value", value);
return execute(builder, HttpMethod.PUT, payload, EtcdResponse.class);
}
/**
* Atomically deletes a key-value pair in etcd.
*
* @param key
* the key
* @param prevIndex
* the modified index of the key
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse compareAndDelete(final String key, int prevIndex) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
builder.queryParam("prevIndex", prevIndex);
return execute(builder, HttpMethod.DELETE, null, EtcdResponse.class);
}
/**
* Atomically deletes a key-value pair in etcd.
*
* @param key
* the key
* @param prevValue
* the previous value of the key
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse compareAndDelete(final String key, String prevValue) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
builder.queryParam("prevValue", prevValue);
return execute(builder, HttpMethod.DELETE, null, EtcdResponse.class);
}
/**
* Creates a directory node in etcd.
*
* @param key
* the key
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse putDir(final String key) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
MultiValueMap payload = new LinkedMultiValueMap<>(1);
payload.set("dir", "true");
return execute(builder, HttpMethod.PUT, payload, EtcdResponse.class);
}
/**
* Creates a directory node in etcd.
*
* @param key
* the key
* @param ttl
* the time-to-live
* @return the response from etcd with the node
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdResponse putDir(String key, int ttl) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
MultiValueMap payload = new LinkedMultiValueMap<>(1);
payload.set("dir", "true");
payload.set("ttl", ttl == -1 ? "" : String.valueOf(ttl));
return execute(builder, HttpMethod.PUT, payload, EtcdResponse.class);
}
public EtcdResponse deleteDir(String key) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
builder.queryParam("dir", "true");
return execute(builder, HttpMethod.DELETE, null, EtcdResponse.class);
}
public EtcdResponse deleteDir(String key, boolean recursive) throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(KEYSPACE);
builder.pathSegment(key);
builder.queryParam("recursive", recursive);
return execute(builder, HttpMethod.DELETE, null, EtcdResponse.class);
}
/**
* Returns a representation of all members in the etcd cluster.
*
* @return the members
* @throws EtcdException
* in case etcd returned an error
*/
public EtcdMemberResponse listMembers() throws EtcdException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(MEMBERSPACE);
return execute(builder, HttpMethod.GET, null, EtcdMemberResponse.class);
}
/**
* {@inheritDoc}
*
* @see InitializingBean#afterPropertiesSet()
*/
@Override
public void afterPropertiesSet() throws Exception {
if (this.requestFactory == null) {
SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
requestFactory.setConnectTimeout(1000);
requestFactory.setReadTimeout(3000);
this.requestFactory = requestFactory;
}
template = new RestTemplate(this.requestFactory);
template.setMessageConverters(Arrays.asList(requestConverter, responseConverter));
if (locationUpdaterEnabled) {
Runnable worker = new Runnable() {
@Override
public void run() {
updateMembers();
}
};
locationUpdater.scheduleAtFixedRate(worker, 5000, 5000, TimeUnit.MILLISECONDS);
}
}
/**
* {@inheritDoc}
*
* @see DisposableBean#destroy()
*/
@Override
public void destroy() throws Exception {
locationUpdater.shutdownNow();
}
/**
* Updates the locations of the etcd cluster members.
*/
private void updateMembers() {
try {
List locations = new ArrayList();
EtcdMemberResponse response = listMembers();
EtcdMember[] members = response.getMembers();
for (EtcdMember member : members) {
String[] clientUrls = member.getClientURLs();
if (clientUrls != null) {
for (String clientUrl : clientUrls) {
try {
String version = template.getForObject(clientUrl + "/version", String.class);
if (version == null) {
locations.add(clientUrl);
}
} catch (RestClientException e) {
log.debug("ignoring URI " + clientUrl + " because of error.", e);
}
}
}
}
if (!locations.isEmpty()) {
this.locations = locations.toArray(new String[locations.size()]);
} else {
log.debug("not updating locations because no location is found");
}
} catch (EtcdException e) {
log.error("Could not update etcd cluster member.", e);
}
}
/**
* Executes the given method on the given location using the given request
* data.
*
* @param uri
* the location
* @param method
* the HTTP method
* @param requestData
* the request data
* @return the etcd response
* @throws EtcdException
* in case etcd returned an error
*/
private T execute(UriComponentsBuilder uriTemplate, HttpMethod method,
MultiValueMap requestData, Class responseType) throws EtcdException {
long startTimeMillis = System.currentTimeMillis();
int retry = -1;
ResourceAccessException lastException = null;
do {
lastException = null;
URI uri = uriTemplate.buildAndExpand(locations[locationIndex]).toUri();
RequestEntity> requestEntity = new RequestEntity<>(requestData, null, method,
uri);
try {
ResponseEntity responseEntity = template.exchange(requestEntity, responseType);
return responseEntity.getBody();
} catch (HttpStatusCodeException e) {
EtcdError error = null;
try {
error = responseConverter.getObjectMapper().readValue(e.getResponseBodyAsByteArray(),
EtcdError.class);
} catch (IOException ex) {
error = null;
}
throw new EtcdException(error, "Failed to execute " + requestEntity + ".", e);
} catch (ResourceAccessException e) {
log.debug("Failed to execute " + requestEntity + ", retrying if possible.", e);
if (locationIndex == locations.length - 1) {
locationIndex = 0;
} else {
locationIndex++;
}
lastException = e;
}
} while (retry <= retryCount && System.currentTimeMillis() - startTimeMillis < retryDuration);
if (lastException != null) {
throw lastException;
} else {
return null;
}
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy