refactor(cli): settings doesn't log anymore (#267)

Removes logging from the `Settings` class. Logging was only used when
loading settings from a file and that functionality is currently only
used by the `UserConfiguration` class of the CLI. So I localized the
loading there. If we wanted to re-introduce a generic loading from file
in the future, we just need to build it with the `IoHost` in mind.

---
By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache-2.0 license

Author: mrgrain

packages/aws-cdk/lib/api/settings.ts

@@ -2,7 +2,6 @@ import * as os from 'os';
 import * as fs_path from 'path';
 import * as fs from 'fs-extra';
 import { ToolkitError } from '../../../@aws-cdk/tmp-toolkit-helpers/src/api';
-import { warning } from '../logging';
 import * as util from '../util';
 
 export type SettingsMap = { [key: string]: any };
@@ -30,27 +29,6 @@ export class Settings {
   ) {
   }
 
-  public async load(fileName: string): Promise<this> {
-    if (this.readOnly) {
-      throw new ToolkitError(
-        `Can't load ${fileName}: settings object is readonly`,
-      );
-    }
-    this.settings = {};
-
-    const expanded = expandHomeDir(fileName);
-    if (await fs.pathExists(expanded)) {
-      this.settings = await fs.readJson(expanded);
-    }
-
-    // See https://github.com/aws/aws-cdk/issues/59
-    this.prohibitContextKey('default-account', fileName);
-    this.prohibitContextKey('default-region', fileName);
-    this.warnAboutContextKey('aws:', fileName);
-
-    return this;
-  }
-
   public async save(fileName: string): Promise<this> {
     const expanded = expandHomeDir(fileName);
     await fs.writeJson(expanded, stripTransientValues(this.settings), {
@@ -106,36 +84,6 @@ export class Settings {
   public unset(path: string[]) {
     this.set(path, undefined);
   }
-
-  private prohibitContextKey(key: string, fileName: string) {
-    if (!this.settings.context) {
-      return;
-    }
-    if (key in this.settings.context) {
-      // eslint-disable-next-line max-len
-      throw new ToolkitError(
-        `The 'context.${key}' key was found in ${fs_path.resolve(
-          fileName,
-        )}, but it is no longer supported. Please remove it.`,
-      );
-    }
-  }
-
-  private warnAboutContextKey(prefix: string, fileName: string) {
-    if (!this.settings.context) {
-      return;
-    }
-    for (const contextKey of Object.keys(this.settings.context)) {
-      if (contextKey.startsWith(prefix)) {
-        // eslint-disable-next-line max-len
-        warning(
-          `A reserved context key ('context.${prefix}') key was found in ${fs_path.resolve(
-            fileName,
-          )}, it might cause surprising behavior and should be removed.`,
-        );
-      }
-    }
-  }
 }
 
 function expandHomeDir(x: string) {

packages/aws-cdk/lib/cli/user-configuration.ts

@@ -1,3 +1,6 @@
+import * as os from 'os';
+import * as fs_path from 'path';
+import * as fs from 'fs-extra';
 import { ToolkitError } from '../../../@aws-cdk/tmp-toolkit-helpers/src/api';
 import { Context, PROJECT_CONTEXT } from '../api/context';
 import { Settings } from '../api/settings';
@@ -174,14 +177,71 @@ export class Configuration {
 }
 
 async function loadAndLog(fileName: string): Promise<Settings> {
-  const ret = new Settings();
-  await ret.load(fileName);
+  const ret = await settingsFromFile(fileName);
   if (!ret.empty) {
     debug(fileName + ':', JSON.stringify(ret.all, undefined, 2));
   }
   return ret;
 }
 
+async function settingsFromFile(fileName: string): Promise<Settings> {
+  let settings;
+  const expanded = expandHomeDir(fileName);
+  if (await fs.pathExists(expanded)) {
+    const data = await fs.readJson(expanded);
+    settings = new Settings(data);
+  } else {
+    settings = new Settings();
+  }
+
+  // See https://github.com/aws/aws-cdk/issues/59
+  prohibitContextKeys(settings, ['default-account', 'default-region'], fileName);
+  warnAboutContextKey(settings, 'aws:', fileName);
+
+  return settings;
+}
+
+function prohibitContextKeys(settings: Settings, keys: string[], fileName: string) {
+  const context = settings.get(['context']);
+  if (!context || typeof context !== 'object') {
+    return;
+  }
+
+  for (const key of keys) {
+    if (key in context) {
+      throw new ToolkitError(
+        `The 'context.${key}' key was found in ${fs_path.resolve(
+          fileName,
+        )}, but it is no longer supported. Please remove it.`,
+      );
+    }
+  }
+}
+
+function warnAboutContextKey(settings: Settings, prefix: string, fileName: string) {
+  const context = settings.get(['context']);
+  if (!context || typeof context !== 'object') {
+    return;
+  }
+
+  for (const contextKey of Object.keys(context)) {
+    if (contextKey.startsWith(prefix)) {
+      warning(
+        `A reserved context key ('context.${prefix}') key was found in ${fs_path.resolve(
+          fileName,
+        )}, it might cause surprising behavior and should be removed.`,
+      );
+    }
+  }
+}
+
+function expandHomeDir(x: string) {
+  if (x.startsWith('~')) {
+    return fs_path.join(os.homedir(), x.slice(1));
+  }
+  return x;
+}
+
 /**
  * Parse CLI arguments into Settings
  *