Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2012 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package com.android.internal.util; |
| 18 | |
| 19 | import android.os.FileUtils; |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 20 | import android.util.Slog; |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 21 | |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 22 | import com.android.internal.util.FileRotator.Rewriter; |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 23 | |
| 24 | import java.io.BufferedInputStream; |
| 25 | import java.io.BufferedOutputStream; |
| 26 | import java.io.File; |
| 27 | import java.io.FileInputStream; |
| 28 | import java.io.FileOutputStream; |
| 29 | import java.io.IOException; |
| 30 | import java.io.InputStream; |
| 31 | import java.io.OutputStream; |
| 32 | |
| 33 | import libcore.io.IoUtils; |
| 34 | |
| 35 | /** |
| 36 | * Utility that rotates files over time, similar to {@code logrotate}. There is |
| 37 | * a single "active" file, which is periodically rotated into historical files, |
| 38 | * and eventually deleted entirely. Files are stored under a specific directory |
| 39 | * with a well-known prefix. |
| 40 | * <p> |
| 41 | * Instead of manipulating files directly, users implement interfaces that |
| 42 | * perform operations on {@link InputStream} and {@link OutputStream}. This |
| 43 | * enables atomic rewriting of file contents in |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 44 | * {@link #rewriteActive(Rewriter, long)}. |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 45 | * <p> |
| 46 | * Users must periodically call {@link #maybeRotate(long)} to perform actual |
| 47 | * rotation. Not inherently thread safe. |
| 48 | */ |
| 49 | public class FileRotator { |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 50 | private static final String TAG = "FileRotator"; |
| 51 | private static final boolean LOGD = true; |
| 52 | |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 53 | private final File mBasePath; |
| 54 | private final String mPrefix; |
| 55 | private final long mRotateAgeMillis; |
| 56 | private final long mDeleteAgeMillis; |
| 57 | |
| 58 | private static final String SUFFIX_BACKUP = ".backup"; |
| 59 | private static final String SUFFIX_NO_BACKUP = ".no_backup"; |
| 60 | |
| 61 | // TODO: provide method to append to active file |
| 62 | |
| 63 | /** |
| 64 | * External class that reads data from a given {@link InputStream}. May be |
| 65 | * called multiple times when reading rotated data. |
| 66 | */ |
| 67 | public interface Reader { |
| 68 | public void read(InputStream in) throws IOException; |
| 69 | } |
| 70 | |
| 71 | /** |
| 72 | * External class that writes data to a given {@link OutputStream}. |
| 73 | */ |
| 74 | public interface Writer { |
| 75 | public void write(OutputStream out) throws IOException; |
| 76 | } |
| 77 | |
| 78 | /** |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 79 | * External class that reads existing data from given {@link InputStream}, |
| 80 | * then writes any modified data to {@link OutputStream}. |
| 81 | */ |
| 82 | public interface Rewriter extends Reader, Writer { |
| 83 | public void reset(); |
| 84 | public boolean shouldWrite(); |
| 85 | } |
| 86 | |
| 87 | /** |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 88 | * Create a file rotator. |
| 89 | * |
| 90 | * @param basePath Directory under which all files will be placed. |
| 91 | * @param prefix Filename prefix used to identify this rotator. |
| 92 | * @param rotateAgeMillis Age in milliseconds beyond which an active file |
| 93 | * may be rotated into a historical file. |
| 94 | * @param deleteAgeMillis Age in milliseconds beyond which a rotated file |
| 95 | * may be deleted. |
| 96 | */ |
| 97 | public FileRotator(File basePath, String prefix, long rotateAgeMillis, long deleteAgeMillis) { |
| 98 | mBasePath = Preconditions.checkNotNull(basePath); |
| 99 | mPrefix = Preconditions.checkNotNull(prefix); |
| 100 | mRotateAgeMillis = rotateAgeMillis; |
| 101 | mDeleteAgeMillis = deleteAgeMillis; |
| 102 | |
| 103 | // ensure that base path exists |
| 104 | mBasePath.mkdirs(); |
| 105 | |
| 106 | // recover any backup files |
| 107 | for (String name : mBasePath.list()) { |
| 108 | if (!name.startsWith(mPrefix)) continue; |
| 109 | |
| 110 | if (name.endsWith(SUFFIX_BACKUP)) { |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 111 | if (LOGD) Slog.d(TAG, "recovering " + name); |
| 112 | |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 113 | final File backupFile = new File(mBasePath, name); |
| 114 | final File file = new File( |
| 115 | mBasePath, name.substring(0, name.length() - SUFFIX_BACKUP.length())); |
| 116 | |
| 117 | // write failed with backup; recover last file |
| 118 | backupFile.renameTo(file); |
| 119 | |
| 120 | } else if (name.endsWith(SUFFIX_NO_BACKUP)) { |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 121 | if (LOGD) Slog.d(TAG, "recovering " + name); |
| 122 | |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 123 | final File noBackupFile = new File(mBasePath, name); |
| 124 | final File file = new File( |
| 125 | mBasePath, name.substring(0, name.length() - SUFFIX_NO_BACKUP.length())); |
| 126 | |
| 127 | // write failed without backup; delete both |
| 128 | noBackupFile.delete(); |
| 129 | file.delete(); |
| 130 | } |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | /** |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 135 | * Delete all files managed by this rotator. |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 136 | */ |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 137 | public void deleteAll() { |
| 138 | final FileInfo info = new FileInfo(mPrefix); |
| 139 | for (String name : mBasePath.list()) { |
| 140 | if (!info.parse(name)) continue; |
| 141 | |
| 142 | // delete each file that matches parser |
| 143 | new File(mBasePath, name).delete(); |
| 144 | } |
| 145 | } |
| 146 | |
| 147 | /** |
| 148 | * Process currently active file, first reading any existing data, then |
| 149 | * writing modified data. Maintains a backup during write, which is restored |
| 150 | * if the write fails. |
| 151 | */ |
| 152 | public void rewriteActive(Rewriter rewriter, long currentTimeMillis) |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 153 | throws IOException { |
| 154 | final String activeName = getActiveName(currentTimeMillis); |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 155 | rewriteSingle(rewriter, activeName); |
| 156 | } |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 157 | |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 158 | @Deprecated |
| 159 | public void combineActive(final Reader reader, final Writer writer, long currentTimeMillis) |
| 160 | throws IOException { |
| 161 | rewriteActive(new Rewriter() { |
| 162 | /** {@inheritDoc} */ |
| 163 | public void reset() { |
| 164 | // ignored |
| 165 | } |
| 166 | |
| 167 | /** {@inheritDoc} */ |
| 168 | public void read(InputStream in) throws IOException { |
| 169 | reader.read(in); |
| 170 | } |
| 171 | |
| 172 | /** {@inheritDoc} */ |
| 173 | public boolean shouldWrite() { |
| 174 | return true; |
| 175 | } |
| 176 | |
| 177 | /** {@inheritDoc} */ |
| 178 | public void write(OutputStream out) throws IOException { |
| 179 | writer.write(out); |
| 180 | } |
| 181 | }, currentTimeMillis); |
| 182 | } |
| 183 | |
| 184 | /** |
| 185 | * Process all files managed by this rotator, usually to rewrite historical |
| 186 | * data. Each file is processed atomically. |
| 187 | */ |
| 188 | public void rewriteAll(Rewriter rewriter) throws IOException { |
| 189 | final FileInfo info = new FileInfo(mPrefix); |
| 190 | for (String name : mBasePath.list()) { |
| 191 | if (!info.parse(name)) continue; |
| 192 | |
| 193 | // process each file that matches parser |
| 194 | rewriteSingle(rewriter, name); |
| 195 | } |
| 196 | } |
| 197 | |
| 198 | /** |
| 199 | * Process a single file atomically, first reading any existing data, then |
| 200 | * writing modified data. Maintains a backup during write, which is restored |
| 201 | * if the write fails. |
| 202 | */ |
| 203 | private void rewriteSingle(Rewriter rewriter, String name) throws IOException { |
| 204 | if (LOGD) Slog.d(TAG, "rewriting " + name); |
| 205 | |
| 206 | final File file = new File(mBasePath, name); |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 207 | final File backupFile; |
| 208 | |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 209 | rewriter.reset(); |
| 210 | |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 211 | if (file.exists()) { |
| 212 | // read existing data |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 213 | readFile(file, rewriter); |
| 214 | |
| 215 | // skip when rewriter has nothing to write |
| 216 | if (!rewriter.shouldWrite()) return; |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 217 | |
| 218 | // backup existing data during write |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 219 | backupFile = new File(mBasePath, name + SUFFIX_BACKUP); |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 220 | file.renameTo(backupFile); |
| 221 | |
| 222 | try { |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 223 | writeFile(file, rewriter); |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 224 | |
| 225 | // write success, delete backup |
| 226 | backupFile.delete(); |
| 227 | } catch (IOException e) { |
| 228 | // write failed, delete file and restore backup |
| 229 | file.delete(); |
| 230 | backupFile.renameTo(file); |
| 231 | throw e; |
| 232 | } |
| 233 | |
| 234 | } else { |
| 235 | // create empty backup during write |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 236 | backupFile = new File(mBasePath, name + SUFFIX_NO_BACKUP); |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 237 | backupFile.createNewFile(); |
| 238 | |
| 239 | try { |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 240 | writeFile(file, rewriter); |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 241 | |
| 242 | // write success, delete empty backup |
| 243 | backupFile.delete(); |
| 244 | } catch (IOException e) { |
| 245 | // write failed, delete file and empty backup |
| 246 | file.delete(); |
| 247 | backupFile.delete(); |
| 248 | throw e; |
| 249 | } |
| 250 | } |
| 251 | } |
| 252 | |
| 253 | /** |
| 254 | * Read any rotated data that overlap the requested time range. |
| 255 | */ |
| 256 | public void readMatching(Reader reader, long matchStartMillis, long matchEndMillis) |
| 257 | throws IOException { |
| 258 | final FileInfo info = new FileInfo(mPrefix); |
| 259 | for (String name : mBasePath.list()) { |
| 260 | if (!info.parse(name)) continue; |
| 261 | |
| 262 | // read file when it overlaps |
| 263 | if (info.startMillis <= matchEndMillis && matchStartMillis <= info.endMillis) { |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 264 | if (LOGD) Slog.d(TAG, "reading matching " + name); |
| 265 | |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 266 | final File file = new File(mBasePath, name); |
| 267 | readFile(file, reader); |
| 268 | } |
| 269 | } |
| 270 | } |
| 271 | |
| 272 | /** |
| 273 | * Return the currently active file, which may not exist yet. |
| 274 | */ |
| 275 | private String getActiveName(long currentTimeMillis) { |
| 276 | String oldestActiveName = null; |
| 277 | long oldestActiveStart = Long.MAX_VALUE; |
| 278 | |
| 279 | final FileInfo info = new FileInfo(mPrefix); |
| 280 | for (String name : mBasePath.list()) { |
| 281 | if (!info.parse(name)) continue; |
| 282 | |
| 283 | // pick the oldest active file which covers current time |
| 284 | if (info.isActive() && info.startMillis < currentTimeMillis |
| 285 | && info.startMillis < oldestActiveStart) { |
| 286 | oldestActiveName = name; |
| 287 | oldestActiveStart = info.startMillis; |
| 288 | } |
| 289 | } |
| 290 | |
| 291 | if (oldestActiveName != null) { |
| 292 | return oldestActiveName; |
| 293 | } else { |
| 294 | // no active file found above; create one starting now |
| 295 | info.startMillis = currentTimeMillis; |
| 296 | info.endMillis = Long.MAX_VALUE; |
| 297 | return info.build(); |
| 298 | } |
| 299 | } |
| 300 | |
| 301 | /** |
| 302 | * Examine all files managed by this rotator, renaming or deleting if their |
| 303 | * age matches the configured thresholds. |
| 304 | */ |
| 305 | public void maybeRotate(long currentTimeMillis) { |
| 306 | final long rotateBefore = currentTimeMillis - mRotateAgeMillis; |
| 307 | final long deleteBefore = currentTimeMillis - mDeleteAgeMillis; |
| 308 | |
| 309 | final FileInfo info = new FileInfo(mPrefix); |
| 310 | for (String name : mBasePath.list()) { |
| 311 | if (!info.parse(name)) continue; |
| 312 | |
| 313 | if (info.isActive()) { |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 314 | if (info.startMillis <= rotateBefore) { |
| 315 | // found active file; rotate if old enough |
| 316 | if (LOGD) Slog.d(TAG, "rotating " + name); |
| 317 | |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 318 | info.endMillis = currentTimeMillis; |
| 319 | |
| 320 | final File file = new File(mBasePath, name); |
| 321 | final File destFile = new File(mBasePath, info.build()); |
| 322 | file.renameTo(destFile); |
| 323 | } |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 324 | } else if (info.endMillis <= deleteBefore) { |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 325 | // found rotated file; delete if old enough |
Jeff Sharkey | 63abc37 | 2012-01-11 18:38:16 -0800 | [diff] [blame^] | 326 | if (LOGD) Slog.d(TAG, "deleting " + name); |
| 327 | |
Jeff Sharkey | a27a3e8 | 2012-01-08 16:41:36 -0800 | [diff] [blame] | 328 | final File file = new File(mBasePath, name); |
| 329 | file.delete(); |
| 330 | } |
| 331 | } |
| 332 | } |
| 333 | |
| 334 | private static void readFile(File file, Reader reader) throws IOException { |
| 335 | final FileInputStream fis = new FileInputStream(file); |
| 336 | final BufferedInputStream bis = new BufferedInputStream(fis); |
| 337 | try { |
| 338 | reader.read(bis); |
| 339 | } finally { |
| 340 | IoUtils.closeQuietly(bis); |
| 341 | } |
| 342 | } |
| 343 | |
| 344 | private static void writeFile(File file, Writer writer) throws IOException { |
| 345 | final FileOutputStream fos = new FileOutputStream(file); |
| 346 | final BufferedOutputStream bos = new BufferedOutputStream(fos); |
| 347 | try { |
| 348 | writer.write(bos); |
| 349 | bos.flush(); |
| 350 | } finally { |
| 351 | FileUtils.sync(fos); |
| 352 | IoUtils.closeQuietly(bos); |
| 353 | } |
| 354 | } |
| 355 | |
| 356 | /** |
| 357 | * Details for a rotated file, either parsed from an existing filename, or |
| 358 | * ready to be built into a new filename. |
| 359 | */ |
| 360 | private static class FileInfo { |
| 361 | public final String prefix; |
| 362 | |
| 363 | public long startMillis; |
| 364 | public long endMillis; |
| 365 | |
| 366 | public FileInfo(String prefix) { |
| 367 | this.prefix = Preconditions.checkNotNull(prefix); |
| 368 | } |
| 369 | |
| 370 | /** |
| 371 | * Attempt parsing the given filename. |
| 372 | * |
| 373 | * @return Whether parsing was successful. |
| 374 | */ |
| 375 | public boolean parse(String name) { |
| 376 | startMillis = endMillis = -1; |
| 377 | |
| 378 | final int dotIndex = name.lastIndexOf('.'); |
| 379 | final int dashIndex = name.lastIndexOf('-'); |
| 380 | |
| 381 | // skip when missing time section |
| 382 | if (dotIndex == -1 || dashIndex == -1) return false; |
| 383 | |
| 384 | // skip when prefix doesn't match |
| 385 | if (!prefix.equals(name.substring(0, dotIndex))) return false; |
| 386 | |
| 387 | try { |
| 388 | startMillis = Long.parseLong(name.substring(dotIndex + 1, dashIndex)); |
| 389 | |
| 390 | if (name.length() - dashIndex == 1) { |
| 391 | endMillis = Long.MAX_VALUE; |
| 392 | } else { |
| 393 | endMillis = Long.parseLong(name.substring(dashIndex + 1)); |
| 394 | } |
| 395 | |
| 396 | return true; |
| 397 | } catch (NumberFormatException e) { |
| 398 | return false; |
| 399 | } |
| 400 | } |
| 401 | |
| 402 | /** |
| 403 | * Build current state into filename. |
| 404 | */ |
| 405 | public String build() { |
| 406 | final StringBuilder name = new StringBuilder(); |
| 407 | name.append(prefix).append('.').append(startMillis).append('-'); |
| 408 | if (endMillis != Long.MAX_VALUE) { |
| 409 | name.append(endMillis); |
| 410 | } |
| 411 | return name.toString(); |
| 412 | } |
| 413 | |
| 414 | /** |
| 415 | * Test if current file is active (no end timestamp). |
| 416 | */ |
| 417 | public boolean isActive() { |
| 418 | return endMillis == Long.MAX_VALUE; |
| 419 | } |
| 420 | } |
| 421 | } |