/**
* 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.hadoop.hive.ql.exec.errors;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.regex.Pattern;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.hadoop.hive.conf.HiveConf;
import org.apache.hadoop.hive.shims.ShimLoader;
import org.apache.hadoop.http.HtmlQuoting;
import org.apache.hadoop.mapred.JobConf;
/**
* TaskLogProcessor reads the logs from failed task attempts and tries to figure
* out what the cause of the error was using various heuristics.
*/
public class TaskLogProcessor {
private final Logger LOG = LoggerFactory.getLogger(TaskLogProcessor.class);
private final Map<ErrorHeuristic, HeuristicStats> heuristics =
new HashMap<ErrorHeuristic, HeuristicStats>();
private final List<String> taskLogUrls = new ArrayList<String>();
// Query is the hive query string i.e. "SELECT * FROM src;" associated with
// this set of tasks logs
private final String query;
public TaskLogProcessor(JobConf conf) {
query = HiveConf.getQueryString(conf);
heuristics.put(new ScriptErrorHeuristic(), new HeuristicStats());
heuristics.put(new MapAggrMemErrorHeuristic(), new HeuristicStats());
heuristics.put(new DataCorruptErrorHeuristic(), new HeuristicStats());
for(ErrorHeuristic e : heuristics.keySet()) {
e.init(query, conf);
}
}
/**
* Adds a task log URL for the heuristics to read through.
* @param url
*/
public void addTaskAttemptLogUrl(String url) {
taskLogUrls.add(url);
}
private static class HeuristicStats {
// The number of times eh has returned non-null errors
private int triggerCount = 0;
// All ErrorAndSolutions that ErrorHeuristic has generated. For the same error, they
// should be the same though it's possible that different file paths etc
// could generate different error messages
private final List<ErrorAndSolution> ens = new ArrayList<ErrorAndSolution>();
HeuristicStats() {
}
int getTriggerCount() {
return triggerCount;
}
void incTriggerCount() {
triggerCount++;
}
List<ErrorAndSolution> getErrorAndSolutions() {
return ens;
}
void addErrorAndSolution(ErrorAndSolution e) {
ens.add(e);
}
}
/**
* Processes the provided task logs using the known error heuristics to get
* the matching errors.
* @return A ErrorAndSolution from the ErrorHeuristic that most frequently
* generated matches. In case of ties, multiple ErrorAndSolutions will be
* returned.
*/
public List<ErrorAndSolution> getErrors() {
for (String urlString : taskLogUrls) {
// Open the log file, and read in a line. Then feed the line into
// each of the ErrorHeuristics. Repeat for all the lines in the log.
URL taskAttemptLogUrl;
try {
taskAttemptLogUrl = new URL(urlString);
} catch (MalformedURLException e) {
LOG.error("Bad task log URL", e);
continue;
}
BufferedReader in;
try {
in = new BufferedReader(
new InputStreamReader(taskAttemptLogUrl.openStream()));
String inputLine;
while ((inputLine = in.readLine()) != null) {
for(ErrorHeuristic e : heuristics.keySet()) {
e.processLogLine(inputLine);
}
}
in.close();
} catch (IOException e) {
LOG.error("Error while reading from task log URL", e);
continue;
}
// Once the lines of the log file have been fed into the ErrorHeuristics,
// see if they have detected anything. If any has, record
// what ErrorAndSolution it gave so we can later return the most
// frequently occurring error
for (Entry<ErrorHeuristic, HeuristicStats> ent : heuristics.entrySet()) {
ErrorHeuristic eh = ent.getKey();
HeuristicStats hs = ent.getValue();
ErrorAndSolution es = eh.getErrorAndSolution();
if (es != null) {
hs.incTriggerCount();
hs.addErrorAndSolution(es);
}
}
}
// Return the errors that occur the most frequently
int max = 0;
for (HeuristicStats hs : heuristics.values()) {
if(hs.getTriggerCount() > max) {
max = hs.getTriggerCount();
}
}
List<ErrorAndSolution> errors = new ArrayList<ErrorAndSolution>();
for (HeuristicStats hs : heuristics.values()) {
if (hs.getTriggerCount() == max) {
if (hs.getErrorAndSolutions().size() > 0) {
// An error heuristic could have generated different ErrorAndSolution
// for each task attempt, but most likely they are the same. Plus,
// one of those is probably good enough for debugging
errors.add(hs.getErrorAndSolutions().get(0));
}
}
}
return errors;
}
/**
* Processes the provided task logs to extract stack traces.
* @return A list of lists of strings where each list of strings represents a stack trace
*/
public List<List<String>> getStackTraces() {
List<List<String>> stackTraces = new ArrayList<List<String>>();
for(String urlString : taskLogUrls) {
// Open the log file, and read the lines, parse out stack traces
URL taskAttemptLogUrl;
try {
taskAttemptLogUrl = new URL(urlString);
} catch(MalformedURLException e) {
throw new RuntimeException("Bad task log url", e);
}
BufferedReader in;
try {
in = new BufferedReader(
new InputStreamReader(taskAttemptLogUrl.openStream()));
String lastLine = null;
boolean lastLineMatched = false;
List<String> stackTrace = null;
// Patterns that match the middle/end of stack traces
Pattern stackTracePattern = Pattern.compile("^\tat .*", Pattern.CASE_INSENSITIVE);
Pattern endStackTracePattern =
Pattern.compile("^\t... [0-9]+ more.*", Pattern.CASE_INSENSITIVE);
String inputLine;
while (true) {
inputLine = in.readLine();
if (inputLine == null) { // EOF:
if (stackTrace != null) {
stackTraces.add(stackTrace);
stackTrace = null;
}
break;
}
inputLine = HtmlQuoting.unquoteHtmlChars(inputLine);
if (stackTracePattern.matcher(inputLine).matches() ||
endStackTracePattern.matcher(inputLine).matches()) {
// We are in a stack trace
if (stackTrace == null) {
// This is the first time we have realized we are in a stack trace. In this case,
// the previous line was the error message, add that to the stack trace as well
stackTrace = new ArrayList<String>();
stackTrace.add(lastLine);
} else if (!lastLineMatched) {
// The last line didn't match a pattern, it is probably an error message, part of
// a string of stack traces related to the same error message so add it to the stack
// trace
stackTrace.add(lastLine);
}
stackTrace.add(inputLine);
lastLineMatched = true;
} else {
if (!lastLineMatched && stackTrace != null) {
// If the last line didn't match the patterns either, the stack trace is definitely
// over
stackTraces.add(stackTrace);
stackTrace = null;
}
lastLineMatched = false;
}
lastLine = inputLine;
}
in.close();
} catch (IOException e) {
throw new RuntimeException("Error while reading from task log url", e);
}
}
return stackTraces;
}
}