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GeezerVison is showing github.com — scyjava/src/scyjava/_jvm.py at main · scijava/scyjava Expand file tree/ Copy path_jvm.pyMore file actions 512 lines (405 loc) · 17.1 KB / Copy path_jvm.pyFile metadata and controls512 lines (405 loc) · 17.1 KB 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 """ Utility functions for working with the Java Virtual Machine. """ import atexit import logging import os import re import subprocess import sys from collections.abc import Sequence from functools import cache from importlib import import_module from pathlib import Path import jgo import jpype import jpype.config import scyjava.config from scyjava._jdk_fetch import resolve_java from scyjava.config import Mode, mode _logger = logging.getLogger(__name__) _startup_callbacks = [] _shutdown_callbacks = [] def jvm_version() -> tuple[int, ...]: """ Gets the version of the JVM as a tuple, with each dot-separated digit as one element. Characters in the version string beyond only numbers and dots are ignored, in line with the java.version system property. Examples: * OpenJDK 17.0.1 -> (17, 0, 1) * OpenJDK 11.0.9.1-internal -> (11, 0, 9, 1) * OpenJDK 1.8.0_312 -> (1, 8, 0) If the JVM is already started, this function returns the equivalent of: jimport('java.lang.System') .getProperty('java.version') .split('.') In case the JVM is not started yet, a best effort is made to deduce the version from the environment without actually starting up the JVM in-process. If the version cannot be deduced, a RuntimeError with the cause is raised. """ if mode == Mode.JEP: System = jimport("java.lang.System") version = str(System.getProperty("java.version")) # Get everything up to the hyphen version = version.split("-")[0] return tuple(map(int, version.split("."))) assert mode == Mode.JPYPE jvm_ver = jpype.getJVMVersion() if jvm_ver and jvm_ver[0]: # JPype already knew the version. # JVM is probably already started. # Or JPype got smarter since 1.3.0. return jvm_ver # JPype was clueless, which means the JVM has probably not started yet. # Let's look for a java executable, and ask via 'java -version'. default_jvm_path = jpype.getDefaultJVMPath() if not default_jvm_path: raise RuntimeError("Cannot glean the default JVM path") # Note: On macOS, JPype may fall back to /usr/libexec/java_home, which # yields a Java home directory as bytes, rather than a JVM library path. default_jvm_path = os.fsdecode(default_jvm_path) _logger.debug(f"Default JVM path from JPype: {default_jvm_path}") # Good ol' macOS! Nothing beats macOS. jvm_path = default_jvm_path.replace( "/Contents/MacOS/libjli.dylib", "/Contents/Home/lib/libjli.dylib" ) p = Path(jvm_path) java = None if not p.exists(): # Try Java 8 macOS dylib path (jre/lib/jli/libjli.dylib vs lib/libjli.dylib). p8 = Path( default_jvm_path.replace( "/Contents/MacOS/libjli.dylib", "/Contents/Home/jre/lib/jli/libjli.dylib", ) ) if p8.exists(): p = p8 if not p.exists(): # Fall back to JAVA_HOME if the dylib path resolution failed. java_home = os.environ.get("JAVA_HOME") if java_home: candidate = Path(java_home) / "bin" / "java" if os.name == "nt": candidate = candidate.with_suffix(".exe") if candidate.is_file(): java = candidate if java is None: raise RuntimeError(f"Invalid default JVM path: {p}") if java is None and p.is_dir(): java = p / "bin" / "java" if os.name == "nt": java = java.with_suffix(".exe") if not java.is_file(): raise RuntimeError(f"No bin/java found inside: {p}") if java is None: for _ in range(3): # The bin folder is always <=3 levels up from libjvm. p = p.parent if p.name == "lib": java = p.parent / "bin" / "java" elif p.name == "bin": java = p / "java" if java is not None: if os.name == "nt": # Good ol' Windows! Nothing beats Windows. java = java.with_suffix(".exe") if not java.is_file(): raise RuntimeError(f"No ../bin/java found at: {p}") break if java is None: raise RuntimeError(f"No java executable found inside: {p}") _logger.debug(f"Invoking `{java} -version`...") try: output = subprocess.check_output( [str(java), "-version"], stderr=subprocess.STDOUT ).decode() except subprocess.CalledProcessError as e: raise RuntimeError("System call to java failed") from e return _jvm_version_str_to_tuple(output, java) def _jvm_version_str_to_tuple(java_version_output: str, java: str) -> tuple[int, ...]: java_version_output = java_version_output.replace("\n", " ").replace("\r", "") m = re.match(r'.*version "(\d+(?:\.\d+)*)', java_version_output) if not m: raise RuntimeError( f"Inscrutable java command output:\n$ {java} -version\n{java_version_output}" ) v = m.group(1) _logger.debug(f"Got Java version: {v}") try: return tuple(map(int, v.split("."))) except ValueError: raise RuntimeError(f"Inscrutable java version: {v}") def start_jvm(options: Sequence[str] | None = None) -> None: """ Explicitly connect to the Java virtual machine (JVM). Only one JVM can be active; does nothing if the JVM has already been started. Calling this function directly is typically not necessary, because the first time a scyjava function needing a JVM is invoked, one is started on the fly with the configuration specified via the scijava.config mechanism. :param options: List of options to pass to the JVM. For example: ['-Dfoo=bar', '-XX:+UnlockExperimentalVMOptions'] See also scyjava.config.add_options. """ # if JVM is already running -- break if jvm_started(): if options is not None and len(options) > 0: _logger.debug(f"Options ignored due to already running JVM: {options}") return assert mode == Mode.JPYPE # retrieve endpoint and repositories from scyjava config endpoints = scyjava.config.endpoints repositories = scyjava.config.get_repositories() # use the logger to notify user that endpoints are being added _logger.debug(f"Adding jars from endpoints {endpoints}") # download Java as appropriate resolve_java() # Note: When JPype finds no JVM library via JAVA_HOME (e.g. JAVA_HOME=/usr # from macOS's /usr/bin/java stub), it falls back to /usr/libexec/java_home, # which yields a Java home directory rather than a JVM library path, and # from which JPype cannot start the JVM. But given that directory as # JAVA_HOME, JPype finds the JVM library inside it. default_jvm_path = jpype.getDefaultJVMPath() if default_jvm_path and os.path.isdir(default_jvm_path): java_home = os.fsdecode(default_jvm_path) _logger.debug(f"Detected JAVA_HOME: {java_home}") os.environ["JAVA_HOME"] = java_home # Fail fast if Java version is too old. JPype 1.6+ dropped Java 8 support. try: ver = jvm_version() if ver < (11,): raise RuntimeError( f"Java {'.'.join(str(v) for v in ver)} is not supported. " "scyjava requires Java 11 or later." ) except RuntimeError as e: if "not supported" in str(e): raise _logger.debug(f"Could not determine JVM version before start: {e}") # get endpoints and add to JPype class path if len(endpoints) > 0: # sort endpoints list, except for the first one endpoints = endpoints[:1] + sorted(endpoints[1:]) _logger.debug("Using endpoints %s", endpoints) # join endpoints list to single concatenated endpoint endpoint = "+".join(endpoints) env = jgo.build( endpoint=endpoint, # update=False, cache_dir=scyjava.config.get_cache_dir(), repositories=repositories, resolver=jgo.maven.PythonResolver(lenient=True), # The following obsolete arguments are from jgo v1: # m2_repo=scyjava.config.get_m2_repo(), # manage_dependencies=scyjava.config.get_manage_deps(), # verbose=scyjava.config.get_verbose(), # shortcuts=scyjava.config.get_shortcuts(), ) jpype.addClassPath(env.modules_dir / "*") jpype.addClassPath(env.jars_dir / "*") # HACK: Try to set JAVA_HOME if it isn't already. if ( "JAVA_HOME" not in os.environ or not os.environ["JAVA_HOME"] or not os.path.isdir(os.environ["JAVA_HOME"]) ): _logger.debug("JAVA_HOME not set. Will try to infer it from sys.path.") libjvm_win = Path("Library") / "jre" / "bin" / "server" / "jvm.dll" libjvm_macos = Path("lib") / "server" / "libjvm.dylib" libjvm_linux = Path("lib") / "server" / "libjvm.so" libjvm_paths = { libjvm_win: Path("Library"), libjvm_macos: Path(), libjvm_linux: Path(), } for p in sys.path: if not p.endswith("site-packages"): continue # e.g. $CONDA_PREFIX/lib/python3.10/site-packages -> $CONDA_PREFIX # But we want it to work outside of Conda as well, theoretically. base = Path(p).parent.parent.parent for libjvm_path, java_home_path in libjvm_paths.items(): if (base / libjvm_path).exists(): java_home = str((base / java_home_path).resolve()) _logger.debug(f"Detected JAVA_HOME: {java_home}") os.environ["JAVA_HOME"] = java_home break # initialize JPype JVM _logger.debug("Starting JVM") if options is None: options = scyjava.config.get_options() kwargs = scyjava.config.get_kwargs() jpype.startJVM(*options, **kwargs) # replace JPype/JVM shutdown handling with our own jpype.config.onexit = False jpype.config.free_resources = False atexit.register(shutdown_jvm) # invoke registered callback functions for callback in _startup_callbacks: callback() def shutdown_jvm() -> None: """Shut down the JVM. This function makes a best effort to clean up Java resources first. In particular, shutdown hooks registered with scyjava.when_jvm_stops are sequentially invoked. Then, if the AWT subsystem has started, all AWT windows (as identified by the java.awt.Window.getWindows() method) are disposed to reduce the risk of GUI resources delaying JVM shutdown. Finally, the jpype.shutdownJVM() function is called. Note that you can set the jpype.config.destroy_jvm flag to request JPype to destroy the JVM explicitly, although setting this flag can lead to delayed shutdown times while the JVM is waiting for threads to finish. Note that if the JVM is not already running, then this function does nothing! In particular, shutdown hooks are skipped in this situation. :raise RuntimeError: if this method is called while in Jep mode. """ if not jvm_started(): return if mode == Mode.JEP: raise RuntimeError("Cannot shut down the JVM in Jep mode.") assert mode == Mode.JPYPE # invoke registered shutdown callback functions for callback in _shutdown_callbacks: try: callback() except Exception as e: # noqa: BLE001 _logger.error(f"Exception during shutdown callback: {e}") # dispose AWT resources if applicable if is_awt_initialized(): Window = jimport("java.awt.Window") for w in Window.getWindows(): w.dispose() # okay to shutdown JVM try: jpype.shutdownJVM() except Exception as e: # noqa: BLE001 _logger.error(f"Exception during JVM shutdown: {e}") def jvm_started() -> bool: """Return true iff a Java virtual machine (JVM) has been started.""" if mode == Mode.JEP: return True assert mode == Mode.JPYPE return jpype.isJVMStarted() def gc() -> None: """ Do a round of Java garbage collection. This function is a shortcut for Java's System.gc(). :raise RuntimeError: If the JVM has not started yet. """ _assert_jvm_started() System = jimport("java.lang.System") System.gc() def memory_total() -> int: """ Get the total amount of memory currently reserved by the JVM. This number will always be less than or equal to memory_max(). In case the JVM was configured with -Xms flag upon startup (e.g. using the scyjava.config.set_heap_min function), the initial value will typically correspond approximately, but not exactly, to the configured value, although it is likely to grow over time as more Java objects are allocated. This function is a shortcut for Java's Runtime.getRuntime().totalMemory(). :return: The total memory in bytes. :raise RuntimeError: if the JVM has not yet been started. """ return int(_runtime().totalMemory()) def memory_max() -> int: """ Get the maximum amount of memory that the JVM will attempt to use. This number will always be greater than or equal to memory_total(). In case the JVM was configured with -Xmx flag upon startup (e.g. using the scyjava.config.set_heap_max function), the value will typically correspond approximately, but not exactly, to the configured value. This function is a shortcut for Java's Runtime.getRuntime().maxMemory(). :return: The maximum memory in bytes. :raise RuntimeError: if the JVM has not yet been started. """ return int(_runtime().maxMemory()) def memory_used() -> int: """ Get the amount of memory currently in use by the JVM. This function is a shortcut for Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory(). :return: The used memory in bytes. :raise RuntimeError: if the JVM has not yet been started. """ return memory_total() - int(_runtime().freeMemory()) def available_processors() -> int: """ Get the number of processors available to the JVM. This function is a shortcut for Java's Runtime.getRuntime().availableProcessors(). :return: The number of available processors. :raise RuntimeError: if the JVM has not yet been started. """ return int(_runtime().availableProcessors()) def is_jvm_headless() -> bool: """ Return true iff Java is running in headless mode. :raise RuntimeError: If the JVM has not started yet. """ if not jvm_started(): raise RuntimeError("JVM has not started yet!") GraphicsEnvironment = scyjava.jimport("java.awt.GraphicsEnvironment") return bool(GraphicsEnvironment.isHeadless()) def is_awt_initialized() -> bool: """ Return true iff the AWT subsystem has been initialized. Java starts up its AWT subsystem automatically and implicitly, as soon as an action is performed requiring it -- for example, if you jimport a java.awt or javax.swing class. This can lead to deadlocks on macOS if you are not running in headless mode and did not invoke those actions via the jpype.setupGuiEnvironment wrapper function; see the Troubleshooting section of the scyjava README for details. """ if not jvm_started(): return False Thread = scyjava.jimport("java.lang.Thread") threads = Thread.getAllStackTraces().keySet() return any(t.getName().startsWith("AWT-") for t in threads) def when_jvm_starts(f) -> None: """ Registers a function to be called when the JVM starts (or immediately). This is useful to defer construction of Java-dependent data structures until the JVM is known to be available. If the JVM has already been started, the function executes immediately. :param f: Function to invoke when scyjava.start_jvm() is called. """ if jvm_started(): # JVM was already started; invoke callback function immediately. f() else: # Add function to the list of callbacks to invoke upon start_jvm(). _startup_callbacks.append(f) def when_jvm_stops(f) -> None: """ Registers a function to be called just before the JVM shuts down. This is useful to perform cleanup of Java-dependent data structures. Note that if the JVM is not already running when shutdown_jvm is called, then these registered callback functions will be skipped! :param f: Function to invoke when scyjava.shutdown_jvm() is called. """ _shutdown_callbacks.append(f) @cache def jimport(class_name: str): """ Import a class from Java to Python. :param class_name: Name of the class to import. :return: A pointer to the class, which can be used to e.g. instantiate objects of that class. """ if mode == Mode.JEP: module_path = class_name.rsplit(".", 1) module = import_module(module_path[0], module_path[1]) return getattr(module, module_path[1]) assert mode == Mode.JPYPE start_jvm() return jpype.JClass(class_name) def _assert_jvm_started(): if not jvm_started(): raise RuntimeError("JVM has not started yet!") def _runtime(): _assert_jvm_started() Runtime = jimport("java.lang.Runtime") return Runtime.getRuntime() |
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