Add metrics instrumentation coverage analyzer script

Scans server/src/routes/*.js with Node.js built-ins to count route
handlers and measure console.* logging coverage per file and in aggregate.
Supports JSON (default) and --format=text table output.

Nightshift-Task: metrics-coverage
Nightshift-Ref: https://github.com/marcus/nightshift

scripts/metrics-coverage.js

@@ -0,0 +1,251 @@
+#!/usr/bin/env node
+/**
+ * metrics-coverage.js — Static analysis script for metrics/logging instrumentation coverage.
+ *
+ * Scans all Express route files in server/src/routes/*.js and app.js to measure
+ * how many route handlers contain logging calls (console.error/console.warn/console.log).
+ *
+ * Usage:
+ *   node scripts/metrics-coverage.js              # JSON output (default)
+ *   node scripts/metrics-coverage.js --format=text  # Human-readable table
+ *
+ * Sample output (captured 2026-03-20):
+ * {
+ *   "files": [
+ *     { "file": "actuals.js", "total": 5, "logged": 5, "unlogged": 0, "coverage": 100 },
+ *     { "file": "bills.js", "total": 6, "logged": 6, "unlogged": 0, "coverage": 100 },
+ *     { "file": "config.js", "total": 2, "logged": 2, "unlogged": 0, "coverage": 100 },
+ *     { "file": "financing.js", "total": 6, "logged": 6, "unlogged": 0, "coverage": 100 },
+ *     { "file": "health.js", "total": 1, "logged": 0, "unlogged": 1, "coverage": 0 },
+ *     { "file": "one-time-expenses.js", "total": 3, "logged": 3, "unlogged": 0, "coverage": 100 },
+ *     { "file": "paychecks.js", "total": 6, "logged": 6, "unlogged": 0, "coverage": 100 },
+ *     { "file": "summary.js", "total": 2, "logged": 2, "unlogged": 0, "coverage": 100 }
+ *   ],
+ *   "app": {
+ *     "has_request_timing_middleware": false,
+ *     "has_error_handling_middleware": false,
+ *     "middleware_count": 11
+ *   },
+ *   "aggregate": {
+ *     "total_handlers": 31,
+ *     "logged_handlers": 30,
+ *     "unlogged_handlers": 1,
+ *     "coverage_pct": 96.77
+ *   }
+ * }
+ */
+
+'use strict';
+
+const fs = require('fs');
+const path = require('path');
+
+const ROUTES_DIR = path.resolve(__dirname, '../server/src/routes');
+const APP_FILE   = path.resolve(__dirname, '../server/src/app.js');
+
+// Regex patterns for route handler definitions.
+// Matches: router.get/post/put/patch/delete( and app.get/post/put/patch/delete(
+const ROUTE_DEF_RE = /\b(?:router|app)\.(get|post|put|patch|delete)\s*\(/g;
+
+// Logging call patterns
+const LOG_RE = /\bconsole\.(error|warn|log)\s*\(/;
+
+/**
+ * Extract individual route handler bodies from source.
+ * Strategy: find each route definition, then walk forward counting
+ * braces to find the closing of the outermost async/function callback.
+ */
+function extractHandlerBodies(src) {
+  const handlers = [];
+  let match;
+  ROUTE_DEF_RE.lastIndex = 0;
+
+  while ((match = ROUTE_DEF_RE.exec(src)) !== null) {
+    const startIdx = match.index;
+    // Find the opening paren of the route call
+    const parenOpen = src.indexOf('(', startIdx);
+    if (parenOpen === -1) continue;
+
+    // Walk from the paren open, tracking paren depth to find the matching close.
+    // The handler callback body will be inside the outer parens.
+    let depth = 0;
+    let bodyStart = -1;
+    let bodyEnd = -1;
+    let inString = false;
+    let stringChar = '';
+    let i = parenOpen;
+
+    while (i < src.length) {
+      const ch = src[i];
+
+      // Basic string tracking (skip contents of string literals)
+      if (!inString && (ch === '"' || ch === "'" || ch === '`')) {
+        inString = true;
+        stringChar = ch;
+        i++;
+        continue;
+      }
+      if (inString) {
+        if (ch === '\\') { i += 2; continue; } // skip escape
+        if (ch === stringChar) inString = false;
+        i++;
+        continue;
+      }
+
+      if (ch === '(') {
+        depth++;
+        if (depth === 1) {
+          // This is the opening of the route call args
+        }
+      } else if (ch === ')') {
+        depth--;
+        if (depth === 0) {
+          bodyEnd = i;
+          break;
+        }
+      } else if (ch === '{' && depth >= 1 && bodyStart === -1) {
+        // First brace inside the outer parens — start of the handler body
+        bodyStart = i;
+      }
+
+      i++;
+    }
+
+    if (bodyStart !== -1 && bodyEnd !== -1) {
+      handlers.push(src.slice(bodyStart, bodyEnd));
+    }
+  }
+
+  return handlers;
+}
+
+/**
+ * Analyse a single route file.
+ */
+function analyseRouteFile(filePath) {
+  const src = fs.readFileSync(filePath, 'utf8');
+  const handlers = extractHandlerBodies(src);
+
+  const logged = handlers.filter(body => LOG_RE.test(body));
+
+  return {
+    file: path.basename(filePath),
+    total: handlers.length,
+    logged: logged.length,
+    unlogged: handlers.length - logged.length,
+    coverage: handlers.length === 0
+      ? null
+      : Math.round((logged.length / handlers.length) * 10000) / 100,
+  };
+}
+
+/**
+ * Analyse app.js for middleware-level instrumentation.
+ */
+function analyseApp(filePath) {
+  const src = fs.readFileSync(filePath, 'utf8');
+
+  // Request timing: morgan, custom middleware checking req.method, Date.now() at top-level use()
+  const hasRequestTiming =
+    /\brequire\s*\(\s*['"]morgan['"]\s*\)/.test(src) ||
+    /app\.use\s*\(.*Date\.now\(\)/.test(src) ||
+    /app\.use\s*\(.*req,\s*res,\s*next/.test(src) && /Date\.now|performance\.now/.test(src);
+
+  // Error handling middleware: app.use((err, req, res, next) => ...)
+  const hasErrorHandling = /app\.use\s*\(\s*(?:\S+\s*,\s*)?\(\s*err\s*,/.test(src);
+
+  // Count top-level app.use() calls (middleware registrations)
+  const middlewareMatches = src.match(/app\.use\s*\(/g) || [];
+
+  return {
+    has_request_timing_middleware: hasRequestTiming,
+    has_error_handling_middleware: hasErrorHandling,
+    middleware_count: middlewareMatches.length,
+  };
+}
+
+function run() {
+  const format = process.argv.includes('--format=text') ? 'text' : 'json';
+
+  // Analyse all route files
+  const routeFiles = fs.readdirSync(ROUTES_DIR)
+    .filter(f => f.endsWith('.js'))
+    .sort();
+
+  const fileResults = routeFiles.map(f =>
+    analyseRouteFile(path.join(ROUTES_DIR, f))
+  );
+
+  // Aggregate
+  const totalHandlers  = fileResults.reduce((s, r) => s + r.total,   0);
+  const loggedHandlers = fileResults.reduce((s, r) => s + r.logged,  0);
+
+  const aggregate = {
+    total_handlers:   totalHandlers,
+    logged_handlers:  loggedHandlers,
+    unlogged_handlers: totalHandlers - loggedHandlers,
+    coverage_pct: totalHandlers === 0
+      ? null
+      : Math.round((loggedHandlers / totalHandlers) * 10000) / 100,
+  };
+
+  const appInfo = analyseApp(APP_FILE);
+
+  const result = {
+    files: fileResults,
+    app: appInfo,
+    aggregate,
+  };
+
+  if (format === 'json') {
+    console.log(JSON.stringify(result, null, 2));
+    return;
+  }
+
+  // Text table
+  const COL_FILE    = 28;
+  const COL_TOTAL   = 7;
+  const COL_LOGGED  = 8;
+  const COL_COVER   = 10;
+
+  const pad = (s, n) => String(s).padEnd(n);
+  const lpad = (s, n) => String(s).padStart(n);
+
+  const hr = '-'.repeat(COL_FILE + COL_TOTAL + COL_LOGGED + COL_COVER + 6);
+
+  console.log('\nMetrics Instrumentation Coverage\n');
+  console.log(
+    pad('Route File', COL_FILE) +
+    lpad('Handlers', COL_TOTAL) +
+    lpad('Logged', COL_LOGGED) +
+    lpad('Coverage', COL_COVER)
+  );
+  console.log(hr);
+
+  for (const r of fileResults) {
+    const cov = r.coverage === null ? 'N/A' : `${r.coverage}%`;
+    console.log(
+      pad(r.file, COL_FILE) +
+      lpad(r.total,  COL_TOTAL) +
+      lpad(r.logged, COL_LOGGED) +
+      lpad(cov,      COL_COVER)
+    );
+  }
+
+  console.log(hr);
+  const aggCov = aggregate.coverage_pct === null ? 'N/A' : `${aggregate.coverage_pct}%`;
+  console.log(
+    pad('TOTAL', COL_FILE) +
+    lpad(aggregate.total_handlers,   COL_TOTAL) +
+    lpad(aggregate.logged_handlers,  COL_LOGGED) +
+    lpad(aggCov, COL_COVER)
+  );
+
+  console.log('\napp.js middleware:');
+  console.log(`  Request timing middleware : ${appInfo.has_request_timing_middleware}`);
+  console.log(`  Error handling middleware : ${appInfo.has_error_handling_middleware}`);
+  console.log(`  app.use() call count      : ${appInfo.middleware_count}`);
+  console.log('');
+}
+
+run();