Proposed way to add breakpoints to easybuild

easybuild/tools/config.py

@@ -231,6 +231,7 @@ def mk_full_default_path(name, prefix=DEFAULT_PREFIX):
         'amdgcn_capabilities',
         'backup_modules',
         'banned_linked_shared_libs',
+        'breakpoints',
         'checksum_priority',
         'container_config',
         'container_image_format',

easybuild/tools/hooks.py

@@ -220,6 +220,34 @@ def find_hook(label, hooks, pre_step_hook=False, post_step_hook=False):
     return res
 
 
+def _bash_breakpoint(*args, **kwargs):
+    """Simple breakpoint hook that opens a bash shell."""
+    old_ps1 = os.environ.get('PS1', '')
+    old_promptcmd = os.environ.get('PROMPT_COMMAND', '')
+    os.environ['PROMPT_COMMAND'] = ''
+    os.environ['PS1'] = 'easybuild-breakpoint> '
+    os.system('bash --norc --noprofile')
+    os.environ['PS1'] = old_ps1
+    os.environ['PROMPT_COMMAND'] = old_promptcmd
+
+
+def _python_breakpoint(*args, **kwargs):
+    """Simple breakpoint hook that opens a Python shell."""
+    print('Python breakpoint reached, entering pdb shell...')
+    print('You can inspect/modify the state of the program from here and use `continue` to proceed.')
+    print('Arguments passed to this hook (will contain EasyBlock object to inspect/modify if available):')
+    print('  args = %s' % (args,))
+    print('  kwargs = %s' % (kwargs,))
+    import pdb
+    pdb.set_trace()
+
+
+breakpoint_types = {
+    'bash': _bash_breakpoint,
+    'python': _python_breakpoint,
+}
+
+
 def run_hook(label, hooks, pre_step_hook=False, post_step_hook=False, args=None, kwargs=None, msg=None):
     """
     Run hook with specified label and return result of calling the hook or None.
@@ -231,14 +259,28 @@ def run_hook(label, hooks, pre_step_hook=False, post_step_hook=False, args=None,
     :param args: arguments to pass to hook function
     :param msg: custom message that is printed when hook is called
     """
+    args = args or []
+    kwargs = kwargs or {}
+
+    breakpoints = build_option('breakpoints')
+    bk_hooks = {}
+    if breakpoints:
+        for bk in breakpoints:
+            bk_type, bk_label = (['bash'] + bk.split(':', 1))[-2:]
+            if bk_type not in breakpoint_types:
+                raise EasyBuildError("Unknown breakpoint type '%s' specified for breakpoint '%s'", bk_type, bk)
+            hook_func = breakpoint_types.get(bk_type)
+            if not bk_label.endswith(HOOK_SUFF):
+                bk_label += HOOK_SUFF
+            bk_hooks[bk_label] = hook_func
+
+    bp_hook = find_hook(label, bk_hooks, pre_step_hook=pre_step_hook, post_step_hook=post_step_hook)
+    if bp_hook:
+        bp_hook(*args, **kwargs)
+
     hook = find_hook(label, hooks, pre_step_hook=pre_step_hook, post_step_hook=post_step_hook)
     res = None
     if hook:
-        if args is None:
-            args = []
-        if kwargs is None:
-            kwargs = {}
-
         if pre_step_hook:
             label = 'pre-' + label
         elif post_step_hook:

easybuild/tools/options.py

@@ -627,6 +627,10 @@ def config_options(self):
                                     None, "store_true", False,),
             'avail-repositories': ("Show all repository types (incl. non-usable)",
                                    None, "store_true", False,),
+            'breakpoints': (
+                "Drop into an interactive shell on the specified steps (use same names as for hooks comma separated)",
+                'strlist', 'store', None
+            ),
             'buildpath': ("Temporary build path", None, 'store', mk_full_default_path('buildpath')),
             'containerpath': ("Location where container recipe & image will be stored", None, 'store',
                               mk_full_default_path('containerpath')),