在实际使用Presto的过程中，经常会有以下的一些需求。
- 添加一个新的Catalog
- 对不再使用的Catalog希望把它删除
- 修改某个Catalog的参数
但在Presto中如果进行上述的修改，需要重启Presto服务才可以生效，这给集群维护带来额外的工作量之外，还给上层应用带来很不好的使用体验。
如果还不能在开发环境很好运行Presto的话，参考在windows的IDEA运行Presto。
观察PrestoServer的run方法，可以知道Presot分了多个模块，而且多个模块依赖airlift（Airlift framework for building REST services）的项目，倒不如说airlift是Presto的根基。说实在话，我对于Presto的理解可能还在管中窥豹的阶段，但是不影响我对它做一些手脚。
1、新增一个Hello world测试接口
在presto-main中com.facebook.presto.server中新增一个CatalogResource，作用和Spring类似吧。
/*
* 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 com.facebook.presto.server;
import javax.inject.Inject;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.core.Response;
/**
* @author Gin
* @since 2018/8/15.
*/
@Path("/v1/catalog")
public class CatalogResource
{
@Inject
public CatalogResource()
{
}
@GET
@Path("test")
public Response test()
{
return Response.ok("Hello world").build();
}
}
在ServerMainModule的setup()的方法中最后一行注册CatalogResource：
// Catalogs
jaxrsBinder(binder).bind(CatalogResource.class);
启动server，访问http://localhost:8080/v1/catalog/test，如果出现Hello World的话，那么后面的步骤才行得通。
2、新增一个Add Connector的RESTful接口
新建CatalogInfo用于接收参数：
package com.facebook.presto.server;
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonProperty;
import java.util.Map;
import static java.util.Objects.requireNonNull;
/**
* @author Gin
* @since 2018/8/17.
*/
public class CatalogInfo
{
private final String catalogName;
private final String connectorName;
private final Map<String, String> properties;
@JsonCreator
public CatalogInfo(
@JsonProperty("catalogName") String catalogName,
@JsonProperty("connectorName") String connectorName,
@JsonProperty("properties")Map<String, String> properties)
{
this.catalogName = requireNonNull(catalogName, "catalogName is null");
this.connectorName = requireNonNull(connectorName, "connectorName is null");
this.properties = requireNonNull(properties, "properties is null");
}
@JsonProperty
public String getCatalogName() {
return catalogName;
}
@JsonProperty
public String getConnectorName() {
return connectorName;
}
@JsonProperty
public Map<String, String> getProperties() {
return properties;
}
}
在CatalogResource中增加对应的接口，用到的服务用注入方法声明。
/*
* 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 com.facebook.presto.server;
import com.facebook.presto.connector.ConnectorId;
import com.facebook.presto.connector.ConnectorManager;
import com.facebook.presto.metadata.InternalNodeManager;
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import io.airlift.discovery.client.Announcer;
import io.airlift.discovery.client.ServiceAnnouncement;
import javax.inject.Inject;
import javax.ws.rs.*;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;
import static com.google.common.base.Strings.nullToEmpty;
import static io.airlift.discovery.client.ServiceAnnouncement.serviceAnnouncement;
import static java.util.Objects.requireNonNull;
/**
* @author Gin
* @since 2018/8/15.
*/
@Path("/v1/catalog")
public class CatalogResource
{
private final ConnectorManager connectorManager;
private final Announcer announcer;
@Inject
public CatalogResource(
ConnectorManager connectorManager,
Announcer announcer)
{
this.connectorManager = requireNonNull(connectorManager, "connectorManager is null");
this.announcer = requireNonNull(announcer, "announcer is null");
}
@GET
@Path("test")
public Response test()
{
return Response.ok("Hello world").build();
}
@PUT
@Consumes(MediaType.APPLICATION_JSON)
@Produces(MediaType.APPLICATION_JSON)
public Response createCatalog(CatalogInfo catalogInfo)
{
requireNonNull(catalogInfo, "catalogInfo is null");
ConnectorId connectorId = connectorManager.createConnection(
catalogInfo.getCatalogName(),
catalogInfo.getConnectorName(),
catalogInfo.getProperties());
updateConnectorIdAnnouncement(announcer, connectorId);
return Response.status(Response.Status.OK).build();
}
private static void updateConnectorIdAnnouncement(Announcer announcer, ConnectorId connectorId)
{
//
// This code was copied from PrestoServer, and is a hack that should be removed when the connectorId property is removed
//
// get existing announcement
ServiceAnnouncement announcement = getPrestoAnnouncement(announcer.getServiceAnnouncements());
// update connectorIds property
Map<String, String> properties = new LinkedHashMap<>(announcement.getProperties());
String property = nullToEmpty(properties.get("connectorIds"));
Set<String> connectorIds = new LinkedHashSet<>(Splitter.on(',').trimResults().omitEmptyStrings().splitToList(property));
connectorIds.add(connectorId.toString());
properties.put("connectorIds", Joiner.on(',').join(connectorIds));
// update announcement
announcer.removeServiceAnnouncement(announcement.getId());
announcer.addServiceAnnouncement(serviceAnnouncement(announcement.getType()).addProperties(properties).build());
announcer.forceAnnounce();
}
private static ServiceAnnouncement getPrestoAnnouncement(Set<ServiceAnnouncement> announcements)
{
for (ServiceAnnouncement announcement : announcements) {
if (announcement.getType().equals("presto")) {
return announcement;
}
}
throw new RuntimeException("Presto announcement not found: " + announcements);
}
}
3、测试RESTful接口
这步需要安装需要的插件，检查插件是否安装。使用postman类似的东西，发送application/json的PUT请求到http://localhost:8080/v1/catalog/，body为
{
"catalogName": "test",
"connectorName": "mysql",
"properties": {
"connection-url":"jdbc:mysql://localhost:3306",
"connection-user":"root",
"connection-password":"root"
}
}
我们可以看到控制台，重新输出了connector的信息：
2018-08-19T14:09:03.502+0800 INFO main com.facebook.presto.server.PrestoServer ======== SERVER STARTED ========
2018-08-19T14:09:23.496+0800 INFO http-worker-133 Bootstrap PROPERTY DEFAULT RUNTIME DESCRIPTION
2018-08-19T14:09:23.496+0800 INFO http-worker-133 Bootstrap connection-password [REDACTED] [REDACTED]
2018-08-19T14:09:23.496+0800 INFO http-worker-133 Bootstrap connection-url null jdbc:mysql://localhost:3306
2018-08-19T14:09:23.496+0800 INFO http-worker-133 Bootstrap connection-user null root
2018-08-19T14:09:23.496+0800 INFO http-worker-133 Bootstrap allow-drop-table false false Allow connector to drop tables
2018-08-19T14:09:23.496+0800 INFO http-worker-133 Bootstrap mysql.auto-reconnect true true
2018-08-19T14:09:23.496+0800 INFO http-worker-133 Bootstrap mysql.connection-timeout 10.00s 10.00s
2018-08-19T14:09:23.496+0800 INFO http-worker-133 Bootstrap mysql.max-reconnects 3 3
2018-08-19T14:09:23.876+0800 INFO http-worker-133 io.airlift.bootstrap.LifeCycleManager Life cycle starting...
2018-08-19T14:09:23.877+0800 INFO http-worker-133 io.airlift.bootstrap.LifeCycleManager Life cycle startup complete. System ready.
接下来要怎么利用，要看大家的脑洞了:)?
参考文献：
Presto技术内幕