org.apache.slider.server.appmaster.web.rest.registry.RegistryResource.java Source code

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Here is the source code for org.apache.slider.server.appmaster.web.rest.registry.RegistryResource.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.apache.slider.server.appmaster.web.rest.registry;

import com.google.inject.Singleton;
import org.apache.hadoop.fs.PathNotFoundException;
import org.apache.hadoop.registry.client.api.RegistryOperations;
import org.apache.hadoop.registry.client.exceptions.AuthenticationFailedException;
import org.apache.hadoop.registry.client.exceptions.InvalidRecordException;
import org.apache.hadoop.registry.client.exceptions.NoPathPermissionsException;
import org.apache.hadoop.registry.client.exceptions.NoRecordException;
import org.apache.hadoop.yarn.webapp.ForbiddenException;
import org.apache.hadoop.yarn.webapp.NotFoundException;
import org.apache.slider.server.appmaster.web.WebAppApi;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.UriInfo;
import java.io.IOException;

/**
 * This is the read-only view of the YARN registry.
 * 
 * Model:
 * <ol>
 *   <li>a tree of nodes</li>
 *   <li>Default view is of children + record</li>
 * </ol>
 * 
 */
@Singleton
public class RegistryResource {
    protected static final Logger log = LoggerFactory.getLogger(RegistryResource.class);
    public static final String SERVICE_PATH = "/{path:.*}";

    private final RegistryOperations registry;

    /**
     * Construct an instance bonded to a registry
     * @param slider slider API
     */
    public RegistryResource(WebAppApi slider) {
        this.registry = slider.getRegistryOperations();
    }

    /**
     * Internal init code, per request
     * @param request incoming request 
     * @param uriInfo URI details
     */
    private void init(HttpServletRequest request, UriInfo uriInfo) {
        log.debug(uriInfo.getRequestUri().toString());
    }

    @GET
    @Produces({ MediaType.APPLICATION_JSON })
    public PathEntryResource getRoot(@Context HttpServletRequest request, @Context UriInfo uriInfo) {
        return lookup("/", request, uriInfo);
    }

    //   {path:.*}

    @Path(SERVICE_PATH)
    @GET
    @Produces({ MediaType.APPLICATION_JSON })
    public PathEntryResource lookup(@PathParam("path") String path, @Context HttpServletRequest request,
            @Context UriInfo uriInfo) {
        init(request, uriInfo);
        return resolvePath(path);
    }

    /**
     * Do the actual processing of requests to responses; can be directly
     * invoked for testing.
     * @param path path to query
     * @return the entry
     * @throws WebApplicationException on any failure.
     */
    public PathEntryResource resolvePath(String path) throws WebApplicationException {
        try {
            PathEntryResource pathEntry = fromRegistry(path);
            if (log.isDebugEnabled()) {
                log.debug("Resolved:\n{}", pathEntry);
            }
            return pathEntry;
        } catch (WebApplicationException e) {
            // rethrow direct
            throw e;
        } catch (PathNotFoundException e) {
            throw new NotFoundException("Not found: " + path);
        } catch (AuthenticationFailedException e) {
            throw new ForbiddenException(path);
        } catch (NoPathPermissionsException e) {
            throw new ForbiddenException(path);
        } catch (Exception e) {
            log.error("Error during generation of response: {}", e, e);
            throw new WebApplicationException(e);
        }
    }

    /**
     * Build from the registry, filling up the children and service records.
     * If there is no service record at the end of the path, that entry is 
     * null
     * @param path path to query
     * @return the built up record
     * @throws IOException problems
     *
     */
    private PathEntryResource fromRegistry(String path) throws IOException {
        PathEntryResource entry = new PathEntryResource();
        try {
            entry.service = registry.resolve(path);
        } catch (NoRecordException e) {
            // ignoring
            log.debug("No record at {}", path);
        } catch (InvalidRecordException e) {
            // swallowing this exception, the sign of "no entry present"
            // "nothing parseable"
            log.warn("Failed to resolve {}: {}", path, e, e);
        }
        entry.nodes = registry.list(path);
        return entry;
    }
}