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ProxyResource.java
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ProxyResource.java
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package com.hubspot.singularity.proxy;
import java.io.IOException;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.ExecutionException;
import java.util.stream.Collectors;
import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.WebApplicationException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.base.Charsets;
import com.google.inject.Inject;
import com.hubspot.singularity.config.ClusterCoordinatorConfiguration;
import com.hubspot.singularity.config.DataCenter;
import com.ning.http.client.AsyncHttpClient;
import com.ning.http.client.AsyncHttpClient.BoundRequestBuilder;
import com.ning.http.client.Response;
public class ProxyResource {
private static final Logger LOG = LoggerFactory.getLogger(ProxyResource.class);
private final AsyncHttpClient httpClient;
private final ClusterCoordinatorConfiguration configuration;
private final ObjectMapper objectMapper;
private final DataCenterLocator dataCenterLocator;
@Inject
public ProxyResource(ClusterCoordinatorConfiguration configuration, AsyncHttpClient httpClient, ObjectMapper objectMapper, DataCenterLocator dataCenterLocator) {
this.configuration = configuration;
this.httpClient = httpClient;
this.objectMapper = objectMapper;
this.dataCenterLocator = dataCenterLocator;
}
/*
* For items where the dataCenter is part of the object, or where a full list is desired.
* Collect and merge results from each configured dataCenter
*/
public <T> List<T> getMergedListResult(HttpServletRequest request, TypeReference<List<T>> clazz) {
return getMergedListResult(request, null, clazz);
}
public <T, Q> List<T> getMergedListResult(HttpServletRequest request, Q body, TypeReference<List<T>> clazz) {
Map<String, String> headers = getHeaders(request);
Map<String, String> params = getParams(request);
return configuration.getDataCenters().parallelStream()
.map((dc) -> proxyRequest(dc, request, body, clazz, headers, params))
.filter(Objects::nonNull)
.flatMap(List::stream)
.collect(Collectors.toList());
}
/*
* Route a request to a particular dataCenter using the requestId to locate the correct Singularity cluster
*/
public <T> T routeByRequestId(HttpServletRequest request, String requestId, TypeReference<T> clazz) {
return routeByRequestId(request, requestId, null, clazz);
}
public <T, Q> T routeByRequestId(HttpServletRequest request, String requestId, Q body, TypeReference<T> clazz) {
Map<String, String> headers = getHeaders(request);
Map<String, String> params = getParams(request);
DataCenter dataCenter = getDataCenterForRequest(requestId);
return proxyRequest(dataCenter, request, body, clazz, headers, params);
}
/*
* Route a request to a particular dataCenter using the request group Id to locate the correct Singularity cluster
*/
<T> T routeByRequestGroupId(HttpServletRequest request, String requestGroupId, TypeReference<T> clazz) {
Map<String, String> headers = getHeaders(request);
Map<String, String> params = getParams(request);
DataCenter dataCenter = getDataCenterForRequestGroup(requestGroupId);
return proxyRequest(dataCenter, request, null, clazz, headers, params);
}
/*
* Route a request to a particular dataCenter using the slaveId/hostname to locate the correct Singularity cluster
*/
<T> T routeBySlaveId(HttpServletRequest request, String slaveId, TypeReference<T> clazz) {
Map<String, String> headers = getHeaders(request);
Map<String, String> params = getParams(request);
DataCenter dataCenter = getDataCenterForSlaveId(slaveId);
return proxyRequest(dataCenter, request, null, clazz, headers, params);
}
<T> T routeByHostname(HttpServletRequest request, String hostname, TypeReference<T> clazz) {
Map<String, String> headers = getHeaders(request);
Map<String, String> params = getParams(request);
DataCenter dataCenter = getDataCenterForSlaveHostname(hostname);
return proxyRequest(dataCenter, request, null, clazz, headers, params);
}
/*
* Route a request to a particular dataCenter using the rack ID to locate the correct Singularity cluster
*/
<T> T routeByRackId(HttpServletRequest request, String rackId, TypeReference<T> clazz) {
Map<String, String> headers = getHeaders(request);
Map<String, String> params = getParams(request);
DataCenter dataCenter = getDataCenterForRackId(rackId);
return proxyRequest(dataCenter, request, null, clazz, headers, params);
}
/*
* Route a request to a particular dataCenter by name, failing if it is not present
*/
<T, Q> T routeByDataCenter(HttpServletRequest request, String dataCenterName, Q body, TypeReference<T> clazz) {
Map<String, String> headers = getHeaders(request);
Map<String, String> params = getParams(request);
DataCenter dataCenter = getDataCenter(dataCenterName);
return proxyRequest(dataCenter, request, body, clazz, headers, params);
}
/*
* Route to the default Singularity cluster
*/
<T> T routeToDefaultDataCenter(HttpServletRequest request, TypeReference<T> clazz) {
return routeToDefaultDataCenter(request, null, clazz);
}
<T, Q> T routeToDefaultDataCenter(HttpServletRequest request, Q body, TypeReference<T> clazz) {
Map<String, String> headers = getHeaders(request);
Map<String, String> params = getParams(request);
DataCenter dataCenter = configuration.getDataCenters().get(0);
return proxyRequest(dataCenter, request, body, clazz, headers, params);
}
/*
* Working with data centers
*/
private String getHost(DataCenter dataCenter) {
return dataCenterLocator.getHost(dataCenter);
}
private DataCenter getDataCenterForRequest(String requestId) {
return dataCenterLocator.getDataCenterForRequest(requestId);
}
private DataCenter getDataCenterForRequestGroup(String requestGroupId) {
return dataCenterLocator.getDataCenterForRequestGroup(requestGroupId);
}
private DataCenter getDataCenterForSlaveId(String slaveId) {
return dataCenterLocator.getDataCenterForSlaveId(slaveId);
}
private DataCenter getDataCenterForSlaveHostname(String hostname) {
return dataCenterLocator.getDataCenterForSlaveHostname(hostname);
}
private DataCenter getDataCenterForRackId(String rackId) {
return dataCenterLocator.getDataCenterForRackId(rackId);
}
private DataCenter getDataCenter(String name) {
return dataCenterLocator.getDataCenter(name);
}
/*
* Generic methods for proxying requests
*/
private <T, Q> T proxyRequest(DataCenter dc, HttpServletRequest request, Q body, TypeReference<T> clazz, Map<String, String> headers, Map<String, String> params) {
String url = String.format("%s://%s%s%s", dc.getScheme(), getHost(dc), request.getContextPath(), request.getPathInfo());
BoundRequestBuilder requestBuilder = startRequestBuilder(request.getMethod(), url);
try {
if (body != null) {
requestBuilder.setBody(objectMapper.writeValueAsBytes(body));
LOG.trace("Added body {} to request", body);
}
} catch (JsonProcessingException jpe) {
LOG.error("Could not write body from object {}", body);
throw new WebApplicationException(jpe, 500);
}
headers.forEach(requestBuilder::addHeader);
params.forEach(requestBuilder::addQueryParameter);
Response response;
try {
response = requestBuilder.execute().get();
} catch (IOException|InterruptedException|ExecutionException ioe) {
LOG.error("Exception while processing request to {}", url, ioe);
return null;
}
try {
if (response.getStatusCode() > 399) {
LOG.error("Request to {} failed ({}:{})", url, response.getStatusCode(), response.getResponseBody(Charsets.UTF_8.toString()));
return null;
} else {
return objectMapper.readValue(response.getResponseBodyAsStream(), clazz);
}
} catch (IOException ioe) {
try {
LOG.warn("Bad response body: {}", response.getResponseBody(Charsets.UTF_8.toString()));
} catch (IOException io) {
LOG.error("Could not print response", io);
}
LOG.error("Request succeeded with status {}, but could not interpret response ({})", response.getStatusCode(), ioe);
}
return null;
}
private BoundRequestBuilder startRequestBuilder(String method, String url) {
switch (method.toUpperCase()) {
case "GET":
return httpClient.prepareGet(url);
case "POST":
return httpClient.preparePost(url);
case "PUT":
return httpClient.preparePut(url);
case "DELETE":
return httpClient.prepareDelete(url);
default:
throw new WebApplicationException(String.format("Not meant to proxy request of method %s", method), 400);
}
}
private Map<String, String> getHeaders(HttpServletRequest request) {
Map<String, String> headers = new HashMap<>();
Enumeration<String> headerNames = request.getHeaderNames();
if (headerNames != null) {
while (headerNames.hasMoreElements()) {
String headerName = headerNames.nextElement();
headers.put(headerName, request.getHeader(headerName));
}
}
return headers;
}
private Map<String, String> getParams(HttpServletRequest request) {
Map<String, String> params = new HashMap<>();
Enumeration<String> parameterNames = request.getParameterNames();
if (parameterNames != null) {
while (parameterNames.hasMoreElements()) {
String parameterName = parameterNames.nextElement();
params.put(parameterName, request.getParameter(parameterName));
LOG.trace("Copied query param {}={}", parameterName, request.getParameter(parameterName));
}
}
return params;
}
}