Issue/582 reference (#583)

* Added create_environment_reference plugin

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## v8.3.0 - ?
 
+- Added create_environment_reference plugin to create reference to environment variables
+- Added the 'value' attribute to std::testing::NullResource
 - Log warning when environment variable is not found by get_env plugin
 - Deprecate get_env_int plugin in favor of int(get_env())
 

model/testing.cf

@@ -21,15 +21,17 @@ entity NullResource extends ManagedResource, PurgeableResource:
         A resource that does nothing, for use in tests and examples
 
         :attr name: the name of this resource
+        :attr value: a value this resource can cary, has no purpose
         :attr agentname: the name of the agent to deploy this resource on
         :attr fail: when true, this resource will always fail on both dryrun and deploy
     """
     string name = "null"
     string agentname = "internal"
+    string value = ""
     bool send_event = true
     bool fail = false
 end
 
 index NullResource(agentname, name)
 
-implement NullResource using std::none
+implement NullResource using std::none

plugins/__init__.py

@@ -41,6 +41,7 @@
 # don't bind to `resources` because this package has a submodule named resources that will bind to `resources` when imported
 import inmanta.resources
 from inmanta import util
+from inmanta.agent.handler import LoggerABC
 from inmanta.ast import NotFoundException, OptionalValueException, RuntimeException
 from inmanta.config import Config
 from inmanta.execute.proxy import DynamicProxy, UnknownException
@@ -1313,3 +1314,40 @@ def json_dumps(obj: "any") -> "string":
     :param obj: The inmanta object that should be serialized as json.
     """
     return json.dumps(obj, default=util.internal_json_encoder)
+
+
+try:
+    from inmanta.references import Reference, reference
+
+    @reference("std::Environment")
+    class EnvironmentReference(Reference[str]):
+        """A reference to fetch environment variables"""
+
+        def __init__(self, name: str | Reference[str]) -> None:
+            """
+            :param name: The name of the environment variable.
+            """
+            super().__init__()
+            self.name = name
+
+        def resolve(self, logger: LoggerABC) -> str:
+            """Resolve the reference"""
+            env_var_name = self.resolve_other(self.name, logger)
+            logger.debug("Resolving environment variable %(name)s", name=self.name)
+            value = os.getenv(env_var_name)
+            if value is None:
+                raise LookupError(f"Environment variable {env_var_name} is not set")
+            return value
+
+    @plugin
+    def create_environment_reference(name: str | Reference[str]) -> Reference[str]:
+        """Create an environment reference
+
+        :param name: The name of the variable to fetch from the environment
+        :return: A reference to what can be resolved to a string
+        """
+        return EnvironmentReference(name=name)
+
+except ImportError:
+    # Reference are not yet supported by this core version
+    pass

plugins/resources.py

@@ -32,7 +32,7 @@
 
 @resource("std::testing::NullResource", agent="agentname", id_attribute="name")
 class Null(ManagedResource, PurgeableResource):
-    fields = ("name", "agentname", "fail")
+    fields = ("name", "agentname", "fail", "value")
 
 
 @resource("std::AgentConfig", agent="agent", id_attribute="agentname")
@@ -61,6 +61,7 @@ class NullProvider(CRUDHandler):
     def read_resource(self, ctx: HandlerContext, resource: PurgeableResource) -> None:
         if resource.fail:
             raise Exception("This resource is set to fail")
+        ctx.debug("Observed value: %(value)s", value=resource.value)
         return
 
     def create_resource(self, ctx: HandlerContext, resource: PurgeableResource) -> None:

tests/test_reference.py

@@ -0,0 +1,54 @@
+"""
+Copyright 2025 Inmanta
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+Contact: [email protected]
+"""
+
+from pytest_inmanta.plugin import Project
+
+from inmanta import const
+
+
+def test_references_resource(project: Project, monkeypatch) -> None:
+
+    project.compile(
+        """
+            import std::testing
+            metavalue = std::create_environment_reference("METATESTENV")
+            value = std::create_environment_reference(metavalue)
+            std::testing::NullResource(agentname="test", name="aaa", value=value)
+        """
+    )
+
+    project.deploy_resource_v2(
+        "std::testing::NullResource",
+        name="aaa",
+        expected_status=const.ResourceState.failed,
+    )
+
+    monkeypatch.setenv("METATESTENV", "TESTENV")
+    monkeypatch.setenv("TESTENV", "testvalue")
+
+    project.compile(
+        """
+            import std::testing
+            metavalue = std::create_environment_reference("METATESTENV")
+            value = std::create_environment_reference(metavalue)
+            std::testing::NullResource(agentname="test", name="aaa", value=value)
+        """
+    )
+
+    result = project.deploy_resource_v2("std::testing::NullResource", name="aaa")
+    assert result.assert_has_logline("Observed value: testvalue")