Generate config on serve and updated git revision method (#587)

* run generate-config on serve

* write the config file only if settings have changed

* read the git commit hash from the current branch, not master

* git sha is now short by default, no need to trim on the about component

frontend/generate-config.js

@@ -1,4 +1,5 @@
 var fs = require('fs');
+const { execSync } = require('child_process');
 
 const CONFIG_FILE_NAME = 'mempool-frontend-config.json';
 const GENERATED_CONFIG_FILE_NAME = 'generated-config.js';
@@ -32,12 +33,13 @@ for (setting in configContent) {
 }
 
 try {
-  gitCommitHash = fs.readFileSync('../.git/refs/heads/master').toString().trim();
+  const command = 'git rev-parse --short HEAD';
+  gitCommitHash = execSync(command).toString('utf8').replace(/[\n\r\s]+$/, '');
 } catch (e) {
   console.log('Could not load git commit info: ' + e.message || e);
 }
 
-const code = `(function (window) {
+const newConfig = `(function (window) {
   window.__env = window.__env || {};${settings.reduce((str, obj) => `${str}
     window.__env.${obj.key} = ${ typeof obj.value === 'string' ? `'${obj.value}'` : obj.value };`, '')}
     window.__env.GIT_COMMIT_HASH = '${gitCommitHash}';
@@ -45,9 +47,17 @@ const code = `(function (window) {
   }(global || this));`;
 
 try {
-  fs.writeFileSync(GENERATED_CONFIG_FILE_NAME, code, 'utf8');
+  const currentConfig = fs.readFileSync(GENERATED_CONFIG_FILE_NAME).toString().trim();
+  if (currentConfig === newConfig) {
+    console.log("Configuration not changed, skipping generation");
+  } else {
+    try {
+      fs.writeFileSync(GENERATED_CONFIG_FILE_NAME, newConfig, 'utf8');
+      console.log('Config file generated');
+    } catch (e) {
+      throw new Error(e);
+    }
+  }
 } catch (e) {
   throw new Error(e);
 }
-
-console.log('Config file generated');

frontend/package.json

@@ -24,9 +24,9 @@
     "tsc": "./node_modules/typescript/bin/tsc",
     "i18n-extract-from-source": "./node_modules/@angular/cli/bin/ng xi18n --ivy --out-file ./src/locale/messages.xlf",
     "i18n-pull-from-transifex": "tx pull -a --parallel --minimum-perc 1 --force",
-    "serve": "ng serve -c local",
+    "serve": "npm run generate-config && ng serve -c local",
-    "serve:stg": "ng serve -c staging",
+    "serve:stg": "npm run generate-config && ng serve -c staging",
-    "serve:local-prod": "ng serve -c local-prod",
+    "serve:local-prod": "npm run generate-config && ng serve -c local-prod",
     "start": "npm run generate-config && npm run sync-assets-dev && ng serve -c local",
     "start:stg": "npm run generate-config && npm run sync-assets-dev && ng serve -c staging",
     "start:local-prod": "npm run generate-config && npm run sync-assets-dev && ng serve -c local-prod",

frontend/src/app/components/about/about.component.ts

@@ -17,7 +17,7 @@ export class AboutComponent implements OnInit {
   backendInfo$: Observable<IBackendInfo>;
   sponsors$: Observable<any>;
   contributors$: Observable<any>;
-  frontendGitCommitHash = this.stateService.env.GIT_COMMIT_HASH.substr(0, 8);
+  frontendGitCommitHash = this.stateService.env.GIT_COMMIT_HASH;
   packetJsonVersion = this.stateService.env.PACKAGE_JSON_VERSION;
   officialMempoolSpace = this.stateService.env.OFFICIAL_MEMPOOL_SPACE;
   showNavigateToSponsor = false;