feat: Add Matcher/ Parser for spec in getConfig

compat/getConfig.ts

@@ -2,6 +2,7 @@ import { YAML } from "../dependencies.ts";
 import { matches } from "../dependencies.ts";
 import { ExpectedExports } from "../types.ts";
 import { ConfigSpec } from "../types.ts";
+import { typeFromProps, TypeFromProps } from "../utils/propertiesMatcher.ts";
 
 const { any, string, dictionary } = matches;
 
@@ -15,7 +16,8 @@ const matchConfig = dictionary([string, any]);
  * @param spec
  * @returns
  */
-export const getConfig = (spec: ConfigSpec): ExpectedExports.getConfig =>
+export const getConfig =
+  (spec: ConfigSpec): ExpectedExports.getConfig =>
   async (effects) => {
     const config = await effects
       .readFile({
@@ -36,3 +38,37 @@ export const getConfig = (spec: ConfigSpec): ExpectedExports.getConfig =>
       },
     };
   };
+
+/**
+ * Call with the configuration to get a standard getConfig for the expected exports
+ * Assumption: start9/config.yaml is where the config will be stored
+ * Throws: Error if there is no file
+ * Throws: Error if the config.yaml isn't yaml nor config shape
+ * @param spec
+ * @returns A funnction for getConfig and the matcher for the spec sent in
+ */
+export const getConfigAndMatcher = <Spec extends ConfigSpec>(
+  spec: Spec
+): [ExpectedExports.getConfig, matches.Parser<unknown, TypeFromProps<Spec>>] => [
+  async (effects) => {
+    const config = await effects
+      .readFile({
+        path: "start9/config.yaml",
+        volumeId: "main",
+      })
+      .then((x) => YAML.parse(x))
+      .then((x) => matchConfig.unsafeCast(x))
+      .catch((e) => {
+        effects.info(`Got error ${e} while trying to read the config`);
+        return undefined;
+      });
+
+    return {
+      result: {
+        config,
+        spec,
+      },
+    };
+  },
+  typeFromProps(spec),
+];