Make load_params into a function that custom modules can access (#15913)

lib/ansible/module_utils/basic.py

@@ -219,10 +219,10 @@ except ImportError:
 
 _literal_eval = literal_eval
 
-# Internal global holding passed in params and constants.  This is consulted
-# in case multiple AnsibleModules are created.  Otherwise each AnsibleModule
-# would attempt to read from stdin.  Other code should not use this directly
-# as it is an internal implementation detail
+# Internal global holding passed in params.  This is consulted in case
+# multiple AnsibleModules are created.  Otherwise each AnsibleModule would
+# attempt to read from stdin.  Other code should not use this directly as it
+# is an internal implementation detail
 _ANSIBLE_ARGS = None
 
 FILE_COMMON_ARGUMENTS=dict(
@@ -520,9 +520,59 @@ def is_executable(path):
             or stat.S_IXGRP & os.stat(path)[stat.ST_MODE]
             or stat.S_IXOTH & os.stat(path)[stat.ST_MODE])
 
+def _load_params():
+    ''' read the modules parameters and store them globally.
 
-class AnsibleFallbackNotFound(Exception):
-    pass
+    This function may be needed for certain very dynamic custom modules which
+    want to process the parameters that are being handed the module.  Since
+    this is so closely tied to the implementation of modules we cannot
+    guarantee API stability for it (it may change between versions) however we
+    will try not to break it gratuitously.  It is certainly more future-proof
+    to call this function and consume its outputs than to implement the logic
+    inside it as a copy in your own code.
+    '''
+    global _ANSIBLE_ARGS
+    if _ANSIBLE_ARGS is not None:
+        buffer = _ANSIBLE_ARGS
+    else:
+        # debug overrides to read args from file or cmdline
+
+        # Avoid tracebacks when locale is non-utf8
+        # We control the args and we pass them as utf8
+        if len(sys.argv) > 1:
+            if os.path.isfile(sys.argv[1]):
+                fd = open(sys.argv[1], 'rb')
+                buffer = fd.read()
+                fd.close()
+            else:
+                buffer = sys.argv[1]
+                if sys.version_info >= (3,):
+                    buffer = buffer.encode('utf-8', errors='surrogateescape')
+        # default case, read from stdin
+        else:
+            if sys.version_info < (3,):
+                buffer = sys.stdin.read()
+            else:
+                buffer = sys.stdin.buffer.read()
+        _ANSIBLE_ARGS = buffer
+
+    try:
+        params = json.loads(buffer.decode('utf-8'))
+    except ValueError:
+        # This helper used too early for fail_json to work.
+        print('\n{"msg": "Error: Module unable to decode valid JSON on stdin.  Unable to figure out what parameters were passed", "failed": true}')
+        sys.exit(1)
+
+    if sys.version_info < (3,):
+        params = json_dict_unicode_to_bytes(params)
+
+    try:
+        return params['ANSIBLE_MODULE_ARGS']
+    except KeyError:
+        # This helper does not have access to fail_json so we have to print
+        # json output on our own.
+        print('\n{"msg": "Error: Module unable to locate ANSIBLE_MODULE_ARGS in json data from stdin.  Unable to figure out what parameters were passed", "failed": true}')
+        sys.exit(1)
 
 def env_fallback(*args, **kwargs):
     ''' Load value from environment '''
@@ -533,6 +583,10 @@ def env_fallback(*args, **kwargs):
         raise AnsibleFallbackNotFound
 
 
+class AnsibleFallbackNotFound(Exception):
+    pass
+
+
 class AnsibleModule(object):
     def __init__(self, argument_spec, bypass_checks=False, no_log=False,
         check_invalid_arguments=True, mutually_exclusive=None, required_together=None,
@@ -1477,48 +1531,13 @@ class AnsibleModule(object):
                     continue
 
     def _load_params(self):
-        ''' read the input and set the params attribute.  Sets the constants as well.'''
+        ''' read the input and set the params attribute.
+
+        This method is for backwards compatibility.  The guts of the function
+        were moved out in 2.1 so that custom modules could read the parameters.
+        '''
         # debug overrides to read args from file or cmdline
-
-        global _ANSIBLE_ARGS
-        if _ANSIBLE_ARGS is not None:
-            buffer = _ANSIBLE_ARGS
-        else:
-            # Avoid tracebacks when locale is non-utf8
-            # We control the args and we pass them as utf8
-            if len(sys.argv) > 1:
-                if os.path.isfile(sys.argv[1]):
-                    fd = open(sys.argv[1], 'rb')
-                    buffer = fd.read()
-                    fd.close()
-                else:
-                    buffer = sys.argv[1]
-                    if sys.version_info >= (3,):
-                        buffer = buffer.encode('utf-8', errors='surrogateescape')
-            # default case, read from stdin
-            else:
-                if sys.version_info < (3,):
-                    buffer = sys.stdin.read()
-                else:
-                    buffer = sys.stdin.buffer.read()
-            _ANSIBLE_ARGS = buffer
-
-        try:
-            params = json.loads(buffer.decode('utf-8'))
-        except ValueError:
-            # This helper used too early for fail_json to work.
-            print('\n{"msg": "Error: Module unable to decode valid JSON on stdin.  Unable to figure out what parameters were passed", "failed": true}')
-            sys.exit(1)
-
-        if sys.version_info < (3,):
-            params = json_dict_unicode_to_bytes(params)
-
-        try:
-            self.params = params['ANSIBLE_MODULE_ARGS']
-        except KeyError:
-            # This helper used too early for fail_json to work.
-            print('\n{"msg": "Error: Module unable to locate ANSIBLE_MODULE_ARGS and ANSIBLE_MODULE_CONSTANTS in json data from stdin.  Unable to figure out what parameters were passed", "failed": true}')
-            sys.exit(1)
+        self.params = _load_params()
 
     def _log_to_syslog(self, msg):
         if HAS_SYSLOG: