From ef5c086b54ba884a48d06c387380221ec0db6aa6 Mon Sep 17 00:00:00 2001
From: antazoey <jules@apeworx.io>
Date: Mon, 17 Jun 2024 13:04:38 -0500
Subject: [PATCH] docs: document environment variable support in
 `ape-config.yaml` files (#2148)

---
 docs/userguides/config.md       | 10 ++++++++++
 src/ape/utils/misc.py           |  2 +-
 tests/functional/test_config.py | 28 ++++++++++++++++++++++++++++
 3 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/docs/userguides/config.md b/docs/userguides/config.md
index b7d58fcc29..0c84ff3f04 100644
--- a/docs/userguides/config.md
+++ b/docs/userguides/config.md
@@ -19,6 +19,16 @@ However, here is a list of common-use cases requiring the `ape-config.yaml` file
 2. Setting up project dependencies: See the [dependencies](#dependencies) section.
 3. Declaring your project's plugins: See the [plugins](#plugins) section.
 
+**Environment Variables**: `ape-config.yaml` files support environment-variable expansion.
+Simply include environment variables (with the `$` prefix) in your config file and Ape will automatically expand them.
+
+```yaml
+plugin:
+  secret_rpc: $MY_SECRET_RPC
+```
+
+This helps keep your secrets out of Ape!
+
 ## Contracts Folder
 
 Specify a different path to your `contracts/` directory.
diff --git a/src/ape/utils/misc.py b/src/ape/utils/misc.py
index 5e36ca3e92..c6c7bed84a 100644
--- a/src/ape/utils/misc.py
+++ b/src/ape/utils/misc.py
@@ -216,7 +216,7 @@ def load_config(path: Path, expand_envars=True, must_exist=False) -> dict:
                                 and is able to be load.
 
     Returns:
-        Dict (dict): Configured settings parsed from a config file.
+        dict: Configured settings parsed from a config file.
     """
     if path.is_file():
         contents = path.read_text()
diff --git a/tests/functional/test_config.py b/tests/functional/test_config.py
index a9effbaf93..2e52d95c33 100644
--- a/tests/functional/test_config.py
+++ b/tests/functional/test_config.py
@@ -1,3 +1,4 @@
+import os
 from pathlib import Path
 from typing import Optional, Union
 
@@ -39,6 +40,33 @@ def test_model_validate_path_contracts_folder():
     assert cfg.contracts_folder == str(path)
 
 
+def test_validate_file():
+    value = "pathtowherever"
+    with create_tempdir() as temp_dir:
+        file = temp_dir / "ape-config.yaml"
+        file.write_text(f"contracts_folder: {value}")
+        actual = ApeConfig.validate_file(file)
+
+    assert actual.contracts_folder == value
+
+
+def test_validate_file_expands_env_vars():
+    secret = "mycontractssecretfolder"
+    env_var_name = "APE_TEST_CONFIG_SECRET_CONTRACTS_FOLDER"
+    os.environ[env_var_name] = secret
+
+    try:
+        with create_tempdir() as temp_dir:
+            file = temp_dir / "ape-config.yaml"
+            file.write_text(f"contracts_folder: ${env_var_name}")
+
+            actual = ApeConfig.validate_file(file)
+            assert actual.contracts_folder == secret
+    finally:
+        if env_var_name in os.environ:
+            del os.environ[env_var_name]
+
+
 def test_deployments(networks_connected_to_tester, owner, vyper_contract_container, project):
     _ = networks_connected_to_tester  # Connection needs to lookup config.