blueprints: add JSON tag to parse JSON from string (#15235)

.vscode/settings.json

@@ -6,13 +6,15 @@
         "!Context scalar",
         "!Enumerate sequence",
         "!Env scalar",
+        "!Env sequence",
         "!Find sequence",
         "!Format sequence",
         "!If sequence",
         "!Index scalar",
         "!KeyOf scalar",
         "!Value scalar",
-        "!AtIndex scalar"
+        "!AtIndex scalar",
+        "!ParseJSON scalar"
     ],
     "typescript.preferences.importModuleSpecifier": "non-relative",
     "typescript.preferences.importModuleSpecifierEnding": "index",

authentik/blueprints/tests/fixtures/tags.yaml

@@ -37,6 +37,7 @@ entries:
     - attrs:
           attributes:
               env_null: !Env [bar-baz, null]
+              json_parse: !ParseJSON '{"foo": "bar"}'
               policy_pk1:
                   !Format [
                       "%s-%s",

authentik/blueprints/tests/test_v1.py

@@ -215,6 +215,7 @@ class TestBlueprintsV1(TransactionTestCase):
                     },
                     "nested_context": "context-nested-value",
                     "env_null": None,
+                    "json_parse": {"foo": "bar"},
                     "at_index_sequence": "foo",
                     "at_index_sequence_default": "non existent",
                     "at_index_mapping": 2,

authentik/blueprints/v1/common.py

@@ -6,6 +6,7 @@ from copy import copy
 from dataclasses import asdict, dataclass, field, is_dataclass
 from enum import Enum
 from functools import reduce
+from json import JSONDecodeError, loads
 from operator import ixor
 from os import getenv
 from typing import Any, Literal, Union
@@ -291,6 +292,22 @@ class Context(YAMLTag):
         return value
 
 
+class ParseJSON(YAMLTag):
+    """Parse JSON from context/env/etc value"""
+
+    raw: str
+
+    def __init__(self, loader: "BlueprintLoader", node: ScalarNode) -> None:
+        super().__init__()
+        self.raw = node.value
+
+    def resolve(self, entry: BlueprintEntry, blueprint: Blueprint) -> Any:
+        try:
+            return loads(self.raw)
+        except JSONDecodeError as exc:
+            raise EntryInvalidError.from_entry(exc, entry) from exc
+
+
 class Format(YAMLTag):
     """Format a string"""
 
@@ -666,6 +683,7 @@ class BlueprintLoader(SafeLoader):
         self.add_constructor("!Value", Value)
         self.add_constructor("!Index", Index)
         self.add_constructor("!AtIndex", AtIndex)
+        self.add_constructor("!ParseJSON", ParseJSON)
 
 
 class EntryInvalidError(SentryIgnoredException):