add credential input access methods

awx/main/models/credential/__init__.py

@@ -385,6 +385,7 @@ class Credential(PasswordFieldsModel, CommonModelNameNotUnique, ResourceMixin):
     def encrypt_field(self, field, ask):
         if not hasattr(self, field):
             return None
+
         encrypted = encrypt_field(self, field, ask=ask)
         if encrypted:
             self.inputs[field] = encrypted
@@ -415,12 +416,12 @@ class Credential(PasswordFieldsModel, CommonModelNameNotUnique, ResourceMixin):
             type_alias = self.credential_type.name
         else:
             type_alias = self.credential_type_id
-        if self.kind == 'vault' and self.inputs.get('vault_id', None):
+        if self.kind == 'vault' and self.has_input('vault_id'):
             if display:
                 fmt_str = six.text_type('{} (id={})')
             else:
                 fmt_str = six.text_type('{}_{}')
-            return fmt_str.format(type_alias, self.inputs.get('vault_id'))
+            return fmt_str.format(type_alias, self.get_input('vault_id'))
         return six.text_type(type_alias)
 
     @staticmethod
@@ -430,6 +431,29 @@ class Credential(PasswordFieldsModel, CommonModelNameNotUnique, ResourceMixin):
             ret[cred.unique_hash()] = cred
         return ret
 
+    def get_input(self, field_name, **kwargs):
+        """
+        Get an injectable and decrypted value for an input field.
+
+        Retrieves the value for a given credential input field name. Return
+        values for secret input fields are decrypted. If the credential doesn't
+        have an input value defined for the given field name, an AttributeError
+        is raised unless a default value is provided.
+
+        :param field_name(str):        The name of the input field.
+        :param default(optional[str]): A default return value to use.
+        """
+        if field_name in self.credential_type.secret_fields:
+            return decrypt_field(self, field_name)
+        if field_name in self.inputs:
+            return self.inputs[field_name]
+        if 'default' in kwargs:
+            return kwargs['default']
+        raise AttributeError(field_name)
+
+    def has_input(self, field_name):
+        return field_name in self.inputs and self.inputs[field_name] not in ('', None)
+
 
 class CredentialType(CommonModelNameNotUnique):
     '''
@@ -611,8 +635,9 @@ class CredentialType(CommonModelNameNotUnique):
                 safe_namespace[field_name] = namespace[field_name] = value
                 continue
 
+            value = credential.get_input(field_name)
+
             if field_name in self.secret_fields:
-                value = decrypt_field(credential, field_name)
                 safe_namespace[field_name] = '**********'
             elif len(value):
                 safe_namespace[field_name] = value

awx/main/tests/functional/test_credential.py

@@ -327,3 +327,51 @@ def test_credential_update_with_prior(organization_factory, credentialtype_ssh):
     assert cred.inputs['username'] == 'joe'
     assert cred.inputs['password'].startswith('$encrypted$')
     assert decrypt_field(cred, 'password') == 'testing123'
+
+
+@pytest.mark.django_db
+def test_credential_get_input(organization_factory):
+    organization = organization_factory('test').organization
+    type_ = CredentialType(
+        kind='vault',
+        name='somevault',
+        managed_by_tower=True,
+        inputs={
+            'fields': [{
+                'id': 'vault_password',
+                'type': 'string',
+                'secret': True,
+            }, {
+                'id': 'vault_id',
+                'type': 'string',
+                'secret': False
+            }]
+        }
+    )
+    type_.save()
+
+    cred = Credential(
+        organization=organization,
+        credential_type=type_,
+        name="Bob's Credential",
+        inputs={'vault_password': 'testing321'}
+    )
+    cred.save()
+    cred.full_clean()
+
+    assert isinstance(cred, Credential)
+    # verify expected exception is raised when attempting to access an unset
+    # input without providing a default
+    with pytest.raises(AttributeError):
+        cred.get_input('vault_id')
+    # verify that the provided default is used for unset inputs
+    assert cred.get_input('vault_id', default='foo') == 'foo'
+    # verify expected exception is raised when attempting to access an undefined
+    # input without providing a default
+    with pytest.raises(AttributeError):
+        cred.get_input('field_not_on_credential_type')
+    # verify that the provided default is used for undefined inputs
+    assert cred.get_input('field_not_on_credential_type', default='bar') == 'bar'
+    # verify return values for encrypted secret fields are decrypted
+    assert cred.inputs['vault_password'].startswith('$encrypted$')
+    assert cred.get_input('vault_password') == 'testing321'