From be3e4d86c2be10a51559dc53305df6cfe5920b70 Mon Sep 17 00:00:00 2001
From: Daniel Gasienica <daniel@gasienica.ch>
Date: Tue, 6 Mar 2018 12:04:37 -0500
Subject: [PATCH] Add `Errors.toLogFormat`

Allows errors to be formatted and sanitized for logging. Removes sensitive paths
such as the app root directory.

Ideally, this module would be called singular `Error` but that is already a
global name. Using `Errors` plural is  similar to Java convention for utilities
such as `Arrays`, `Collections`, `Files`, etc. See:
https://stackoverflow.com/a/11673838
---
 js/modules/types/errors.js        | 17 ++++++++++++++
 test/modules/types/errors_test.js | 39 +++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 js/modules/types/errors.js
 create mode 100644 test/modules/types/errors_test.js

diff --git a/js/modules/types/errors.js b/js/modules/types/errors.js
new file mode 100644
index 00000000000..7754bb15c4e
--- /dev/null
+++ b/js/modules/types/errors.js
@@ -0,0 +1,17 @@
+/* eslint-env node */
+
+const Path = require('path');
+
+const toError = require('ensure-error');
+
+
+const APP_ROOT_PATH = Path.join(__dirname, '..', '..', '..');
+const APP_ROOT_PATH_PATTERN = new RegExp(APP_ROOT_PATH, 'g');
+
+//      toLogFormat :: Error -> String
+exports.toLogFormat = (error) => {
+  const normalizedError = toError(error);
+  const stackWithoutPrivatePaths =
+    normalizedError.stack.replace(APP_ROOT_PATH_PATTERN, '<REDACTED_PATH>');
+  return stackWithoutPrivatePaths;
+};
diff --git a/test/modules/types/errors_test.js b/test/modules/types/errors_test.js
new file mode 100644
index 00000000000..74a9f4e5142
--- /dev/null
+++ b/test/modules/types/errors_test.js
@@ -0,0 +1,39 @@
+const Path = require('path');
+
+const { assert } = require('chai');
+
+const Errors = require('../../../js/modules/types/errors');
+
+
+const APP_ROOT_PATH = Path.join(__dirname, '..', '..', '..');
+
+describe('Errors', () => {
+  describe('toLogFormat', () => {
+    it('should redact sensitive paths in stack trace', () => {
+      try {
+        throw new Error('boom');
+      } catch (error) {
+        assert.include(
+          error.stack,
+          APP_ROOT_PATH,
+          'Unformatted stack has sensitive paths'
+        );
+
+        const formattedStack = Errors.toLogFormat(error);
+        assert.notInclude(
+          formattedStack,
+          APP_ROOT_PATH,
+          'Formatted stack does not have sensitive paths'
+        );
+        assert.include(
+          formattedStack,
+          '<REDACTED_PATH>',
+          'Formatted stack has redactions'
+        );
+        return;
+      }
+      // eslint-disable-next-line no-unreachable
+      assert.fail('Expected error to be thrown.');
+    });
+  });
+});