stages: add org.osbuild.nginx.conf

Add new stage for writing an nginx configuration file.

stages/org.osbuild.nginx.conf

@@ -0,0 +1,85 @@
+#!/usr/bin/python3
+"""
+Write nginx configuration
+"""
+
+import os
+import sys
+
+import osbuild.api
+from osbuild.util.path import in_tree
+
+SCHEMA = r"""
+"additionalProperties": false,
+"properties": {
+  "path": {
+    "type": "string",
+    "description": "Config file location",
+    "default": "/etc/nginx/nginx.conf",
+    "pattern": "^\\/(?!\\.\\.)((?!\\/\\.\\.\\/).)+$"
+  },
+  "config": {
+    "type": "object",
+    "properties": {
+      "listen": {
+        "type": "string",
+        "description": "The address and/or port on which the server will accept requests",
+        "default": "*:80"
+      },
+      "root": {
+        "type": "string",
+        "description": "The root directory for requests",
+        "default": "/usr/share/nginx/html"
+      },
+      "pid": {
+        "type": "string",
+        "description": "File that will store the process ID of the main process",
+        "default": "/run/nginx.pid"
+      },
+      "daemon": {
+        "type": "boolean",
+        "description": "Whether nginx should become a daemon",
+        "default": true
+      }
+    }
+  }
+}
+"""
+
+def main(tree, options):
+    path = options.get("path", "etc/nginx/nginx.conf").lstrip("/")
+
+    config = options.get("config", {})
+    listen = config.get("listen", "*:80")
+    pid = config.get("pid", "/run/nginx.pid")
+    if config.get("daemon", True):
+        daemon = "on"
+    else:
+        daemon = "off"
+    root = config.get("root", "/usr/share/nginx/html")
+
+    target = os.path.join(tree, path)
+    if not in_tree(target, tree, must_exist=False):
+        raise ValueError(f"config file path {target} not in tree")
+
+    content = f"""events {{}}
+http {{
+  server {{
+    listen {listen};
+    root {root};
+  }}
+}}
+
+pid {pid};
+daemon {daemon};
+"""
+
+    with open(target, "w") as f:
+        f.write(content)
+
+    return 0
+
+
+if __name__ == "__main__":
+    args = osbuild.api.arguments()
+    sys.exit(main(args["tree"], args["options"]))