Revert the go2rtc startup script to str.format substitution

Restores create_config.py to its state on master. The config API check
rejects any stream source whose {FRIGATE_*} placeholders it cannot
resolve with substitute_frigate_vars, and for every source it accepts,
str.format() at startup either produces the same string or fails and
stops go2rtc startup. Changing the startup script is therefore not
needed for the fix, and leaving it alone avoids a conflict with dev,
which already moved this script to the new env helpers.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docker/main/rootfs/usr/local/go2rtc/create_config.py

@@ -3,6 +3,7 @@
 import json
 import os
 import sys
+from pathlib import Path
 from typing import Any
 
 from ruamel.yaml import YAML
@@ -24,6 +25,15 @@ sys.path.remove("/opt/frigate")
 
 yaml = YAML()
 
+FRIGATE_ENV_VARS = {k: v for k, v in os.environ.items() if k.startswith("FRIGATE_")}
+# read docker secret files as env vars too
+if os.path.isdir("/run/secrets"):
+    for secret_file in os.listdir("/run/secrets"):
+        if secret_file.startswith("FRIGATE_"):
+            FRIGATE_ENV_VARS[secret_file] = (
+                Path(os.path.join("/run/secrets", secret_file)).read_text().strip()
+            )
+
 config_file = find_config_file()
 
 try:
@@ -103,7 +113,7 @@ for name in list(go2rtc_config.get("streams", {})):
 
     if isinstance(stream, str):
         try:
-            formatted_stream = substitute_frigate_vars(stream)
+            formatted_stream = stream.format(**FRIGATE_ENV_VARS)
             if is_restricted_go2rtc_source(formatted_stream):
                 print(
                     f"[ERROR] Stream '{name}' uses a restricted source (echo/expr/exec) which is disabled by default for security. "
@@ -112,7 +122,7 @@ for name in list(go2rtc_config.get("streams", {})):
                 del go2rtc_config["streams"][name]
                 continue
             go2rtc_config["streams"][name] = formatted_stream
-        except (KeyError, ValueError) as e:
+        except KeyError as e:
             print(
                 "[ERROR] Invalid substitution found, see https://docs.frigate.video/configuration/restream#advanced-restream-configurations for more info."
             )
@@ -122,7 +132,7 @@ for name in list(go2rtc_config.get("streams", {})):
         filtered_streams = []
         for i, stream_item in enumerate(stream):
             try:
-                formatted_stream = substitute_frigate_vars(stream_item)
+                formatted_stream = stream_item.format(**FRIGATE_ENV_VARS)
                 if is_restricted_go2rtc_source(formatted_stream):
                     print(
                         f"[ERROR] Stream '{name}' item {i + 1} uses a restricted source (echo/expr/exec) which is disabled by default for security. "
@@ -131,7 +141,7 @@ for name in list(go2rtc_config.get("streams", {})):
                     continue
 
                 filtered_streams.append(formatted_stream)
-            except (KeyError, ValueError) as e:
+            except KeyError as e:
                 print(
                     "[ERROR] Invalid substitution found, see https://docs.frigate.video/configuration/restream#advanced-restream-configurations for more info."
                 )