Add --kernel-make-path-relative option

Author: rkdarst

README.md

@@ -95,6 +95,11 @@ These are envkernel-specific options:
   used as a template for all kernel options (`--language`,
   `--kernel-cmd`, etc).  Also, any other file in this directory (such
   as logos) are copied to the new kernel (like kernel.js in irkernel).
+* `--kernel-make-path-relative` removes an absolute path from the
+  kernel command (mainly useful with `--kernel-template`).  This would
+  be useful, for example, where you are setting up an lmod install and
+  the absolute path of the module might change, but you want it to
+  always run Python relative to that module anyway.
 * `--env=NAME=VALUE`.  Set these environment variables when running
   the kernel.  These are actually just saved in the `kernel.json` file
   under the `env` key, which is used by Jupyter itself.  So, this is

envkernel.py

@@ -119,6 +119,9 @@ def setup(self):
                             help="Python command to run (default 'python')")
         parser.add_argument('--kernel-cmd',
                             help="Kernel command to run, separated by spaces.  If this is given, --python is not used.")
+        parser.add_argument('--kernel-make-path-relative', action='store_true',
+                            help="Remove any leading absolute path from the kernel command.  Mainly "
+                                 "useful with --kernel-template.")
         parser.add_argument('--language',
                             help="Language to put into kernel file (default based on --kernel)")
         parser.add_argument('--env', action='append', default=[],
@@ -172,6 +175,9 @@ def setup(self):
             self.kernel['argv'][0] = args.python
         if args.display_name:
             self.kernel['display_name'] = args.display_name
+        # Make the kernel path relative
+        if args.kernel_make_path_relative:
+            self.kernel['argv'][0] = self.kernel['argv'][0].rsplit('/', 1)[-1]
         # Copy logos from upstream packages, if exists
         self.logos = None
         if self.kernel['language'] == 'python':

test_envkernel.py

@@ -121,6 +121,17 @@ def test_template_copyfiles(d, mode):
     assert os.path.exists(pjoin(kern['dir'], 'A.txt'))
     assert open(pjoin(kern['dir'], 'A.txt')).read() == 'LMNO'
 
+@all_modes(['conda'])
+def test_template_make_path_relative(d, mode):
+    os.environ['JUPYTER_PATH'] = pjoin(d, 'share/jupyter')
+    subprocess.call("python -m ipykernel install --name=aaa-ipy --display-name=BBB --prefix=%s"%d, shell=True)
+    # First test it without, ensure it has the full path
+    kern = install(d, "%s --kernel-template aaa-ipy MOD1"%mode)
+    assert kern['k'][0] != 'python' # This is an absolete path
+    # Now test it with --kernel-make-path-relative and ensure it's relative
+    kern = install(d, "%s --kernel-template aaa-ipy --kernel-make-path-relative MOD1"%mode)
+    assert kern['k'][0] == 'python' # This is an absolete path
+
 def test_help():
     """Test that the global -h option works and prints module names"""
     p = subprocess.Popen("python -m envkernel -h", shell=True, stdout=subprocess.PIPE)