| // Copyright 2017 The Bazel Authors. All rights reserved. |
| // |
| // 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.google.devtools.build.lib.worker; |
| |
| import static java.nio.charset.StandardCharsets.UTF_8; |
| |
| import com.google.auto.value.AutoValue; |
| import com.google.common.base.Preconditions; |
| import com.google.common.base.Throwables; |
| import com.google.devtools.build.lib.vfs.FileSystemUtils; |
| import com.google.devtools.build.lib.vfs.Path; |
| import java.io.IOException; |
| |
| /** A well-formatted error message that is easy to read and easy to create. */ |
| @AutoValue |
| abstract class ErrorMessage { |
| abstract String message(); |
| |
| @Override |
| public String toString() { |
| return message(); |
| } |
| |
| public static Builder builder() { |
| return new Builder(); |
| } |
| |
| public static final class Builder { |
| private String message = "Unknown error"; |
| private Path logFile; |
| private String logText = ""; |
| private int logSizeLimit = Integer.MAX_VALUE; |
| private Exception exception; |
| |
| private Builder() {} |
| |
| /** Sets the main text of this error message. */ |
| public Builder message(String message) { |
| Preconditions.checkNotNull(message); |
| this.message = message.isEmpty() ? "Unknown error" : message.trim(); |
| return this; |
| } |
| |
| /** Sets the log file that should be printed as part of the error message. */ |
| public Builder logFile(Path logFile) { |
| Preconditions.checkNotNull(logFile); |
| try { |
| this.logFile = logFile; |
| return logText(FileSystemUtils.readContent(logFile, UTF_8)); |
| } catch (IOException e) { |
| logSizeLimit(Integer.MAX_VALUE); |
| return logText( |
| "ERROR: IOException while trying to read log file:\n" |
| + Throwables.getStackTraceAsString(e)); |
| } |
| } |
| |
| /** |
| * Sets additional text, which is to be presented as a log file in the error message. |
| * |
| * <p>If the log originally comes from a file, it is recommended to use {@link #logFile} |
| * instead, because then the path to the log file can be printed together with the message. |
| */ |
| public Builder logText(String logText) { |
| Preconditions.checkNotNull(logText); |
| // Set the log text to "(empty)" when the passed in string is empty, otherwise error messages |
| // like "Something failed. Check below log for details:" would be pretty confusing for users. |
| this.logText = logText.isEmpty() ? "(empty)" : logText.trim(); |
| return this; |
| } |
| |
| /** |
| * If the log file or text of this error message is longer than the character limit set via this |
| * method, it will be truncated so that only the last X characters of the log are printed. |
| */ |
| public Builder logSizeLimit(int logSizeLimit) { |
| Preconditions.checkArgument(logSizeLimit > 0, "logSizeLimit must be positive"); |
| this.logSizeLimit = logSizeLimit; |
| return this; |
| } |
| |
| /** Lets the error message contain the details of an exception. */ |
| public Builder exception(Exception e) { |
| this.exception = e; |
| return this; |
| } |
| |
| /** Builds and returns the formatted error message. */ |
| public ErrorMessage build() { |
| StringBuilder sb = new StringBuilder(message); |
| |
| if (exception != null) { |
| sb.append("\n\n---8<---8<--- Exception details ---8<---8<---\n"); |
| sb.append(Throwables.getStackTraceAsString(exception).trim()); |
| sb.append("\n---8<---8<--- End of exception details ---8<---8<---"); |
| } |
| |
| if (!logText.isEmpty()) { |
| sb.append("\n\n---8<---8<--- Start of log"); |
| if (logText.length() > logSizeLimit) { |
| sb.append(" snippet"); |
| } |
| if (logFile != null) { |
| sb.append(", file at "); |
| sb.append(logFile.getPathString()); |
| } |
| sb.append(" ---8<---8<---\n"); |
| |
| // If the length of the log is longer than the limit, print only the last part. |
| if (logText.length() > logSizeLimit) { |
| sb.append("[... truncated ...]\n"); |
| sb.append(logText, logText.length() - logSizeLimit, logText.length()); |
| sb.append("\n---8<---8<--- End of log snippet, "); |
| sb.append(logText.length() - logSizeLimit); |
| sb.append(" chars omitted ---8<---8<---"); |
| } else { |
| sb.append(logText); |
| sb.append("\n---8<---8<--- End of log ---8<---8<---"); |
| } |
| } |
| |
| return new AutoValue_ErrorMessage(sb.toString()); |
| } |
| } |
| } |