site-wide default config

Author: Heerpa

README.md

@@ -162,6 +162,49 @@ moving the conda environment.
 
 No registry edits, no GPO, no per-user configuration needed.
 
+### Site-wide default configuration (all-users installs)
+
+When picasso-workflow is installed for all users, individual users may not
+have their own `config.yaml` yet.  An administrator can place a shared
+default at:
+
+| Platform | Site config path |
+|---|---|
+| Windows | `C:\ProgramData\picasso_workflow\config.yaml` |
+| macOS / Linux | `/etc/picasso_workflow/config.yaml` |
+
+Config files are **deep-merged** in this priority order (highest wins):
+
+1. Per-user — `~/.config/picasso_workflow/config.yaml`
+2. Site-wide — path above
+3. Bundled package default
+
+Each file only needs to contain the keys it wants to override.  For
+example, a site config that sets shared cluster and Confluence defaults
+while leaving everything else to the package default:
+
+```yaml
+Confluence:
+  URL: "https://confluence.example.com"
+  Space: "PAINT"
+SlurmLoginNodes:
+  hpccluster: hpcl8001
+ClusterEnvironment:
+  anaconda_module: "anaconda/3/2023.03"
+  conda_env: "picasso-workflow"
+```
+
+Users then only need their own config if they want to override something
+specific (e.g. their personal Confluence page or a different template
+path).  Keys they do not specify are inherited from the site config.
+
+To create the directory and drop in the config on Windows (elevated prompt):
+
+```powershell
+New-Item -ItemType Directory -Force "C:\ProgramData\picasso_workflow"
+# then copy or create config.yaml there
+```
+
 ### macOS deployment — single-user app bundle
 
 On macOS the standard way to make a Python GUI launchable from Finder (or
@@ -197,8 +240,8 @@ easily accessible:
   to `~/Desktop` while holding `Cmd+Alt`
 
 **Icon** — the script converts `picasso_workflow/picasso-workflow.ico`
-to the macOS `.icns` format automatically using `sips` and `iconutil`
-(both are built into macOS).  No extra tools needed.
+to the macOS `.icns` format automatically using Pillow (installed with
+the package) and `iconutil` (built into macOS).  No extra tools needed.
 
 Re-run the script after upgrading the package or moving the conda
 environment.

picasso_workflow/__init__.py

@@ -66,26 +66,69 @@ def config_logger():
     )
 
 
+def _deep_merge(base: dict, override: dict) -> dict:
+    """Return a new dict with override merged on top of base, recursively."""
+    result = base.copy()
+    for key, val in override.items():
+        if (
+            key in result
+            and isinstance(result[key], dict)
+            and isinstance(val, dict)
+        ):
+            result[key] = _deep_merge(result[key], val)
+        else:
+            result[key] = val
+    return result
+
+
+def _site_config_path() -> Path:
+    """Return the platform-appropriate site-wide config path."""
+    if sys.platform == "win32":
+        base = Path(os.environ.get("ProgramData", r"C:\ProgramData"))
+    else:
+        base = Path("/etc")
+    return base / "picasso_workflow" / "config.yaml"
+
+
+def _load_yaml(path) -> dict:
+    with open(path, "r") as f:
+        return yaml.safe_load(f) or {}
+
+
 def load_config():
-    """Load the picasso-workflow configuration yaml file"""
-    # 1. User config path
-    user_config = Path.home() / ".config" / "picasso_workflow" / "config.yaml"
-    if user_config.exists():
-        with open(user_config, "r") as f:
-            return yaml.safe_load(f)
-    # 2. Fallback to package default
+    """Load the picasso-workflow configuration yaml file.
+
+    Configs are deep-merged in increasing priority order so that
+    higher-priority files only need to specify the keys they override:
+
+      1. Bundled package default (config.yaml / config_template.yaml)
+      2. Site-wide admin config  (C:\\ProgramData\\picasso_workflow\\config.yaml
+                                  or /etc/picasso_workflow/config.yaml)
+      3. Per-user config         (~/.config/picasso_workflow/config.yaml)
+    """
+    # 1. Package default
     try:
-        default_config = importlib.resources.files("picasso_workflow").joinpath(
+        pkg_config = importlib.resources.files("picasso_workflow").joinpath(
             "config.yaml"
         )
-        with open(default_config, "r") as f:
-            return yaml.safe_load(f)
-    except FileNotFoundError:
-        template_config = importlib.resources.files("picasso_workflow").joinpath(
+        config = _load_yaml(pkg_config)
+    except (FileNotFoundError, TypeError):
+        template = importlib.resources.files("picasso_workflow").joinpath(
             "config_template.yaml"
         )
-        with open(template_config, "r") as f:
-            return yaml.safe_load(f)
+        config = _load_yaml(template)
+
+    # 2. Site-wide admin config (optional)
+    site_config = _site_config_path()
+    if site_config.exists():
+        config = _deep_merge(config, _load_yaml(site_config))
+
+    # 3. Per-user config (optional)
+    user_config = Path.home() / ".config" / "picasso_workflow" / "config.yaml"
+    if user_config.exists():
+        config = _deep_merge(config, _load_yaml(user_config))
+
+    return config
 
 
 config_logger()

picasso_workflow/config_template.yaml

@@ -1,5 +1,12 @@
-# default located in picasso-workflow/picasso_workflow folder
-# user-specific version can be in ~/.config/picasso_workflow/config.yaml or %APPDATA%\picasso_workflow\config.yaml
+# Bundled package default — lowest priority.
+#
+# Config loading order (deep-merged, highest priority wins):
+#   1. Per-user:   ~/.config/picasso_workflow/config.yaml
+#   2. Site-wide:  C:\ProgramData\picasso_workflow\config.yaml  (Windows)
+#                  /etc/picasso_workflow/config.yaml             (macOS/Linux)
+#   3. This file:  bundled package default
+#
+# Each file only needs to specify the keys it wants to override.
 Templates:
   TemplateName: "/local/path/to/template"
 TestData: