[GR-38116] Minor fixes observed during experiments with sandboxed embedding usecase

PullRequest: graalpython/2228

Author: timfel

docs/user/Packages.md

@@ -43,3 +43,47 @@ Note that to try extensions on GraalVM's Python runtime, you have to download, b
 ### Using `pip`
 
 The `pip` package installer is available and working when using a `venv`.
+
+### Including packages in a Java application
+
+When using Python from Java via the GraalVM embedder APIs, a bit of preparationis required to make packages available to the runtime.
+After a venv is created and any desired packages are installed, this venv is made available to the Java embedded Python by setting a context option.
+A good idea is to include the entire venv folder as a resource, and use Java's resource API:
+
+```java
+String venvExePath = getClass().
+        getClassLoader().
+        getResource(Paths.get("venv", "bin", "graalpython").toString()).
+        getPath();
+
+Context ctx = Context.newBuilder("python").
+        allowIO(true).
+        option("python.Executable", venvExePath).
+        build();
+
+ctx.eval("python", "import site");
+```
+
+The initial `import site` loads the Python standard library module `site`, which sets up the library paths.
+To do so, it uses the path of the currently running Python executable.
+For a language like Python, which is built around the filesystem, this makes sense, but in our Java embedding context, we do not have a Python executable running.
+This is what the `python.Executable` option is for: it reports which executable _would be_ running if we were running Python directly inside our venv.
+That is enough to make the machinery work and any packages inside the venv available to the embedded Python in Java.
+
+A simple venv is already quite heavy, because it comes with the machinery to install more packages.
+For a Java distribution, we can strip the venv down somewhat without much trouble.
+Just run these inside the top-level venv directory:
+```shell
+find . -type d -name "__pycache__" -exec rm -rf "{}" ";"
+rmdir include
+rm bin/*
+rmdir bin
+rm lib/python3.*/site-packages/easy_install.py
+rm -rf lib/python3.*/site-packages/pip*
+```
+
+Some packages may require the following, but most do not, so you can also remove these, but be aware that it _may_ break a few packages:
+```shell
+rm -rf lib/python3.*/site-packages/setuptools*
+rm -rf lib/python3.*/site-packages/pkg_resources*
+```

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/capi/CApiContext.java

@@ -938,10 +938,6 @@ public static boolean isPointerToPrimitive(LLVMType llvmType) {
     @TruffleBoundary
     public static CApiContext ensureCapiWasLoaded(Node node, PythonContext context, String name, String path) throws IOException, ImportException, ApiInitException {
         if (!context.hasCApiContext()) {
-            if (!context.getEnv().isNativeAccessAllowed()) {
-                throw new ImportException(null, name, path, ErrorMessages.NATIVE_ACCESS_NOT_ALLOWED);
-            }
-
             Env env = context.getEnv();
 
             String libPythonName = "libpython" + context.getSoAbi();
@@ -968,6 +964,9 @@ public static CApiContext ensureCapiWasLoaded(Node node, PythonContext context,
                  */
                 throw e.getExceptionForReraise();
             } catch (RuntimeException e) {
+                if (!context.getEnv().isNativeAccessAllowed()) {
+                    throw new ImportException(null, name, path, ErrorMessages.NATIVE_ACCESS_NOT_ALLOWED);
+                }
                 throw new ApiInitException(wrapJavaException(e, node), name, ErrorMessages.CAPI_LOAD_ERROR, capiFile.getAbsoluteFile().getPath());
             }
         }

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/EmulatedPosixSupport.java

@@ -975,7 +975,7 @@ private static long[] unixStat(TruffleFile file, LinkOption... linkOptions) thro
                         LAST_ACCESS_TIME,
                         LAST_MODIFIED_TIME,
                         UNIX_CTIME), linkOptions);
-        return setTimestamps(attributes, new long[]{
+        return setTimestamps(attributes, UNIX_CTIME, new long[]{
                         attributes.get(UNIX_MODE),
                         attributes.get(UNIX_INODE),
                         attributes.get(UNIX_DEV),
@@ -1001,7 +1001,7 @@ private long[] posixStat(TruffleFile file, LinkOption... linkOptions) throws IOE
                         UNIX_GROUP,
                         UNIX_PERMISSIONS), linkOptions);
         final Set<PosixFilePermission> posixFilePermissions = attributes.get(UNIX_PERMISSIONS);
-        return setTimestamps(attributes, new long[]{
+        return setTimestamps(attributes, CREATION_TIME, new long[]{
                         posixPermissionsToMode(fileTypeBitsFromAttributes(attributes), posixFilePermissions),
                         getEmulatedInode(file), // ino
                         0, // dev
@@ -1040,7 +1040,7 @@ private long[] basicStat(TruffleFile file, LinkOption... linkOptions) throws IOE
             mode |= 0100;
         }
         int inode = getEmulatedInode(file);
-        return setTimestamps(attributes, new long[]{
+        return setTimestamps(attributes, CREATION_TIME, new long[]{
                         mode,
                         inode, // ino
                         0, // dev
@@ -1053,10 +1053,10 @@ private long[] basicStat(TruffleFile file, LinkOption... linkOptions) throws IOE
         });
     }
 
-    private static long[] setTimestamps(Attributes attributes, long[] statResult) {
+    private static long[] setTimestamps(Attributes attributes, TruffleFile.AttributeDescriptor<FileTime> ctimeDescriptor, long[] statResult) {
         FileTime atime = attributes.get(LAST_ACCESS_TIME);
         FileTime mtime = attributes.get(LAST_MODIFIED_TIME);
-        FileTime ctime = attributes.get(UNIX_CTIME);
+        FileTime ctime = attributes.get(ctimeDescriptor);
         statResult[7] = fileTimeToSeconds(atime);
         statResult[8] = fileTimeToSeconds(mtime);
         statResult[9] = fileTimeToSeconds(ctime);