reorg

Author: tlambert03

src/scyjava/_cjdk_fetch.py

@@ -2,8 +2,12 @@
 
 import logging
 import os
+import shutil
+import subprocess
 from typing import TYPE_CHECKING
 
+import jpype
+
 if TYPE_CHECKING:
     from pathlib import Path
 
@@ -14,6 +18,34 @@
 _DEFAULT_JAVA_VERSION = "11"
 
 
+def ensure_jvm_available(raise_on_error: bool = True) -> None:
+    """Ensure that the JVM is available, or raise if `raise_on_error` is True."""
+    if not is_jvm_available():
+        cjdk_fetch_java(raise_on_error=raise_on_error)
+    if not shutil.which("mvn"):
+        cjdk_fetch_maven(raise_on_error=raise_on_error)
+
+
+def is_jvm_available() -> bool:
+    """Return True if the JVM is available, suppressing stderr on macos."""
+    from unittest.mock import patch
+
+    subprocess_check_output = subprocess.check_output
+
+    def _silent_check_output(*args, **kwargs):
+        # also suppress stderr on calls to subprocess.check_output
+        kwargs.setdefault("stderr", subprocess.DEVNULL)
+        return subprocess_check_output(*args, **kwargs)
+
+    try:
+        with patch.object(subprocess, "check_output", new=_silent_check_output):
+            jpype.getDefaultJVMPath()
+    # on Darwin, may raise a CalledProcessError when invoking `/user/libexec/java_home`
+    except (jpype.JVMNotFoundException, subprocess.CalledProcessError):
+        return False
+    return True
+
+
 def cjdk_fetch_java(
     vendor: str = "", version: str = "", raise_on_error: bool = True
 ) -> None:
@@ -25,7 +57,7 @@ def cjdk_fetch_java(
             raise ImportError(
                 "No JVM found. Please install `cjdk` to use the fetch_java feature."
             ) from e
-        _logger.info("cjdk is not installed. Skipping automatic fetching of java.")
+        _logger.info("JVM not found. Please install `cjdk` fetch java automatically.")
         return
 
     if not vendor:
@@ -47,7 +79,9 @@ def cjdk_fetch_maven(url: str = "", sha: str = "", raise_on_error: bool = True)
             raise ImportError(
                 "Please install `cjdk` to use the fetch_java feature."
             ) from e
-        _logger.info("cjdk is not installed. Skipping automatic fetching of Maven.")
+        _logger.info(
+            "Maven not found. Please install `cjdk` fetch maven automatically."
+        )
         return
 
     # if url was passed as an argument, or env_var, use it with provided sha

src/scyjava/_jvm.py

@@ -6,7 +6,6 @@
 import logging
 import os
 import re
-import shutil
 import subprocess
 import sys
 from functools import lru_cache
@@ -17,7 +16,7 @@
 import jpype.config
 from jgo import jgo
 
-from scyjava._cjdk_fetch import cjdk_fetch_java, cjdk_fetch_maven
+from scyjava._cjdk_fetch import ensure_jvm_available
 import scyjava.config
 from scyjava.config import Mode, mode
 
@@ -120,10 +119,12 @@ def start_jvm(options=None, *, fetch_java: bool | None = None) -> None:
         List of options to pass to the JVM.
         For example: ['-Dfoo=bar', '-XX:+UnlockExperimentalVMOptions']
     :param fetch_java:
-        Whether to automatically fetch a JRE (and/or maven) using
+        Whether to automatically fetch a JRE (and maven) using
         [`cjdk`](https://github.com/cachedjdk/cjdk) if java and maven executables are
-        not found. Requires `cjdk` to be installed. See README for details.
+        not found. Requires `cjdk` to be installed, either manually, or via the
+        `scyjava[cjdk]` extra.
             - If `None` (default), then fetching will only occur if `cjdk` is available.
+              (A log info will be issued if `cjdk` is not available.)
             - If `True`, an exception will be raised if `cjdk` is not available.
             - If `False`, no attempt to import `cjdk` is be made.
     """
@@ -141,14 +142,11 @@ def start_jvm(options=None, *, fetch_java: bool | None = None) -> None:
     # use the logger to notify user that endpoints are being added
     _logger.debug("Adding jars from endpoints {0}".format(endpoints))
 
-    if fetch_java is not False and not is_jvm_available():
-        cjdk_fetch_java(raise_on_error=fetch_java is True)
+    if fetch_java is not False:
+        ensure_jvm_available(raise_on_error=fetch_java is True)
 
     # get endpoints and add to JPype class path
     if len(endpoints) > 0:
-        if not shutil.which("mvn") and fetch_java is not False:
-            cjdk_fetch_maven(raise_on_error=fetch_java is True)
-
         endpoints = endpoints[:1] + sorted(endpoints[1:])
         _logger.debug("Using endpoints %s", endpoints)
         _, workspace = jgo.resolve_dependencies(
@@ -355,28 +353,6 @@ def is_jvm_headless() -> bool:
     return bool(GraphicsEnvironment.isHeadless())
 
 
-def is_jvm_available() -> bool:
-    """
-    Return True if the JVM is available, suppressing stderr on macos.
-    """
-    from unittest.mock import patch
-
-    subprocess_check_output = subprocess.check_output
-
-    def _silent_check_output(*args, **kwargs):
-        # also suppress stderr on calls to subprocess.check_output
-        kwargs.setdefault("stderr", subprocess.DEVNULL)
-        return subprocess_check_output(*args, **kwargs)
-
-    try:
-        with patch.object(subprocess, "check_output", new=_silent_check_output):
-            jpype.getDefaultJVMPath()
-    # on Darwin, may raise a CalledProcessError when invoking `/user/libexec/java_home`
-    except (jpype.JVMNotFoundException, subprocess.CalledProcessError):
-        return False
-    return True
-
-
 def is_awt_initialized() -> bool:
     """
     Return true iff the AWT subsystem has been initialized.