Harden smtpwebhook delivery and service runtime

config.js

@@ -3,17 +3,38 @@ const AWS = require('aws-sdk');
 
 dotenv.config();
 
+function integerFromEnv(name, fallback) {
+  const value = process.env[name];
+  if (value === undefined || value === '') return fallback;
+  return Number(value);
+}
+
 module.exports = {
-  WEBHOOK_URL: process.env.WEBHOOK_URL || 'https://enkhprqr4n2t.x.pipedream.net/',
+  WEBHOOK_URL: process.env.WEBHOOK_URL,
-  PORT: process.env.PORT || 25,
+  PORT: integerFromEnv('PORT', 25),
-  MAX_FILE_SIZE: process.env.MAX_FILE_SIZE || 5 * 1024 * 1024,
+  MAX_FILE_SIZE: integerFromEnv('MAX_FILE_SIZE', 5 * 1024 * 1024),
+  MAX_MESSAGE_SIZE: integerFromEnv('MAX_MESSAGE_SIZE', 25 * 1024 * 1024),
+  MAX_SMTP_CLIENTS: integerFromEnv('MAX_SMTP_CLIENTS', 50),
+  SMTP_SOCKET_TIMEOUT: integerFromEnv('SMTP_SOCKET_TIMEOUT', 5 * 60 * 1000),
+  SMTP_CLOSE_TIMEOUT: integerFromEnv('SMTP_CLOSE_TIMEOUT', 10 * 1000),
+  SMTP_ALLOWED_IPS: (process.env.SMTP_ALLOWED_IPS || '')
+    .split(',')
+    .map(ip => ip.trim())
+    .filter(Boolean),
   BUCKET_NAME: process.env.S3_BUCKET_NAME,
   SMTP_SECURE: process.env.SMTP_SECURE === 'true',
-  WEBHOOK_CONCURRENCY: process.env.WEBHOOK_CONCURRENCY || 5,
+  TLS_KEY_PATH: process.env.TLS_KEY_PATH,
+  TLS_CERT_PATH: process.env.TLS_CERT_PATH,
+  WEBHOOK_CONCURRENCY: integerFromEnv('WEBHOOK_CONCURRENCY', 5),
+  WEBHOOK_QUEUE_RETRIES: integerFromEnv('WEBHOOK_QUEUE_RETRIES', 10),
+  WEBHOOK_QUEUE_RETRY_DELAY: integerFromEnv('WEBHOOK_QUEUE_RETRY_DELAY', 60 * 1000),
+  WEBHOOK_QUEUE_TIMEOUT: integerFromEnv('WEBHOOK_QUEUE_TIMEOUT', 35 * 1000),
+  SPOOL_DIR: process.env.SPOOL_DIR || '/var/lib/smtpwebhook/spool',
+  LOG_DIR: process.env.LOG_DIR || '/var/lib/smtpwebhook/logs',
 
   s3: new AWS.S3({
     region: process.env.AWS_REGION,
     accessKeyId: process.env.AWS_ACCESS_KEY_ID,
     secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY
   })
-};
+};

package-lock.json

@@ -9,9 +9,12 @@
                 "@aws-sdk/lib-storage": "^3.x.x",
                 "aws-sdk": "^2.x",
                 "axios": "^1.7.7",
+                "better-queue": "^3.8.12",
                 "dotenv": "^16.4.5",
                 "mailparser": "^3.7.1",
-                "smtp-server": "^3.13.5"
+                "smtp-server": "^3.13.5",
+                "winston": "^3.x.x",
+                "winston-daily-rotate-file": "^4.x.x"
             }
         },
         "node_modules/@aws-crypto/crc32": {
@@ -886,6 +889,24 @@
                 "node": ">=16.0.0"
             }
         },
+        "node_modules/@colors/colors": {
+            "version": "1.6.0",
+            "resolved": "https://registry.npmjs.org/@colors/colors/-/colors-1.6.0.tgz",
+            "integrity": "sha512-Ir+AOibqzrIsL6ajt3Rz3LskB7OiMVHqltZmspbW/TJuTVuyOMirVqAkjfY6JISiLHgyNqicAC8AyHHGzNd/dA==",
+            "engines": {
+                "node": ">=0.1.90"
+            }
+        },
+        "node_modules/@dabh/diagnostics": {
+            "version": "2.0.3",
+            "resolved": "https://registry.npmjs.org/@dabh/diagnostics/-/diagnostics-2.0.3.tgz",
+            "integrity": "sha512-hrlQOIi7hAfzsMqlGSFyVucrx38O+j6wiGOf//H2ecvIEqYN4ADBSS2iLMh5UFyDunCNniUIPk/q3riFv45xRA==",
+            "dependencies": {
+                "colorspace": "1.1.x",
+                "enabled": "2.0.x",
+                "kuler": "^2.0.0"
+            }
+        },
         "node_modules/@selderee/plugin-htmlparser2": {
             "version": "0.11.0",
             "resolved": "https://registry.npmjs.org/@selderee/plugin-htmlparser2/-/plugin-htmlparser2-0.11.0.tgz",
@@ -1538,6 +1559,16 @@
                 "node": ">=16.0.0"
             }
         },
+        "node_modules/@types/triple-beam": {
+            "version": "1.3.5",
+            "resolved": "https://registry.npmjs.org/@types/triple-beam/-/triple-beam-1.3.5.tgz",
+            "integrity": "sha512-6WaYesThRMCl19iryMYP7/x2OVgCtbIVflDGFpWnb9irXI3UjYE4AzmYuiUKY1AJstGijoY+MgUszMgRxIYTYw=="
+        },
+        "node_modules/async": {
+            "version": "3.2.6",
+            "resolved": "https://registry.npmjs.org/async/-/async-3.2.6.tgz",
+            "integrity": "sha512-htCUDlxyyCLMgaM3xXg0C0LW2xqfuQ6p05pCEIsXuyQ+a1koYKTuBMzRNwmybfLgvJDMd0r1LTn4+E0Ti6C2AA=="
+        },
         "node_modules/asynckit": {
             "version": "0.4.0",
             "resolved": "https://registry.npmjs.org/asynckit/-/asynckit-0.4.0.tgz",
@@ -1605,9 +1636,10 @@
             }
         },
         "node_modules/axios": {
-            "version": "1.7.7",
+            "version": "1.10.0",
-            "resolved": "https://registry.npmjs.org/axios/-/axios-1.7.7.tgz",
+            "resolved": "https://registry.npmjs.org/axios/-/axios-1.10.0.tgz",
-            "integrity": "sha512-S4kL7XrjgBmvdGut0sN3yJxqYzrDOnivkBiN0OFs6hLiUam3UPvswUo0kqGyhqUZGEOytHyumEdXsAkgCOUf3Q==",
+            "integrity": "sha512-/1xYAC4MP/HEG+3duIhFr4ZQXR4sQXOIe+o6sdqzeykGLx6Upp/1p8MHqhINOvGeP7xyNHe7tsiJByc4SSVUxw==",
+            "license": "MIT",
             "dependencies": {
                 "follow-redirects": "^1.15.6",
                 "form-data": "^4.0.0",
@@ -1641,6 +1673,21 @@
                 }
             ]
         },
+        "node_modules/better-queue": {
+            "version": "3.8.12",
+            "resolved": "https://registry.npmjs.org/better-queue/-/better-queue-3.8.12.tgz",
+            "integrity": "sha512-D9KZ+Us+2AyaCz693/9AyjTg0s8hEmkiM/MB3i09cs4MdK1KgTSGJluXRYmOulR69oLZVo2XDFtqsExDt8oiLA==",
+            "dependencies": {
+                "better-queue-memory": "^1.0.1",
+                "node-eta": "^0.9.0",
+                "uuid": "^9.0.0"
+            }
+        },
+        "node_modules/better-queue-memory": {
+            "version": "1.0.4",
+            "resolved": "https://registry.npmjs.org/better-queue-memory/-/better-queue-memory-1.0.4.tgz",
+            "integrity": "sha512-SWg5wFIShYffEmJpI6LgbL8/3Dqhku7xI1oEiy6FroP9DbcZlG0ZDjxvPdP9t7hTGW40IpIcC6zVoGT1oxjOuA=="
+        },
         "node_modules/bowser": {
             "version": "2.11.0",
             "resolved": "https://registry.npmjs.org/bowser/-/bowser-2.11.0.tgz",
@@ -1673,6 +1720,46 @@
                 "url": "https://github.com/sponsors/ljharb"
             }
         },
+        "node_modules/color": {
+            "version": "3.2.1",
+            "resolved": "https://registry.npmjs.org/color/-/color-3.2.1.tgz",
+            "integrity": "sha512-aBl7dZI9ENN6fUGC7mWpMTPNHmWUSNan9tuWN6ahh5ZLNk9baLJOnSMlrQkHcrfFgz2/RigjUVAjdx36VcemKA==",
+            "dependencies": {
+                "color-convert": "^1.9.3",
+                "color-string": "^1.6.0"
+            }
+        },
+        "node_modules/color-convert": {
+            "version": "1.9.3",
+            "resolved": "https://registry.npmjs.org/color-convert/-/color-convert-1.9.3.tgz",
+            "integrity": "sha512-QfAUtd+vFdAtFQcC8CCyYt1fYWxSqAiK2cSD6zDB8N3cpsEBAvRxp9zOGg6G/SHHJYAT88/az/IuDGALsNVbGg==",
+            "dependencies": {
+                "color-name": "1.1.3"
+            }
+        },
+        "node_modules/color-name": {
+            "version": "1.1.3",
+            "resolved": "https://registry.npmjs.org/color-name/-/color-name-1.1.3.tgz",
+            "integrity": "sha512-72fSenhMw2HZMTVHeCA9KCmpEIbzWiQsjN+BHcBbS9vr1mtt+vJjPdksIBNUmKAW8TFUDPJK5SUU3QhE9NEXDw=="
+        },
+        "node_modules/color-string": {
+            "version": "1.9.1",
+            "resolved": "https://registry.npmjs.org/color-string/-/color-string-1.9.1.tgz",
+            "integrity": "sha512-shrVawQFojnZv6xM40anx4CkoDP+fZsw/ZerEMsW/pyzsRbElpsL/DBVW7q3ExxwusdNXI3lXpuhEZkzs8p5Eg==",
+            "dependencies": {
+                "color-name": "^1.0.0",
+                "simple-swizzle": "^0.2.2"
+            }
+        },
+        "node_modules/colorspace": {
+            "version": "1.1.4",
+            "resolved": "https://registry.npmjs.org/colorspace/-/colorspace-1.1.4.tgz",
+            "integrity": "sha512-BgvKJiuVu1igBUF2kEjRCZXol6wiiGbY5ipL/oVPwm0BL9sIpMIzM8IK7vwuxIIzOXMV3Ey5w+vxhm0rR/TN8w==",
+            "dependencies": {
+                "color": "^3.1.3",
+                "text-hex": "1.0.x"
+            }
+        },
         "node_modules/combined-stream": {
             "version": "1.0.8",
             "resolved": "https://registry.npmjs.org/combined-stream/-/combined-stream-1.0.8.tgz",
@@ -1778,6 +1865,11 @@
                 "url": "https://dotenvx.com"
             }
         },
+        "node_modules/enabled": {
+            "version": "2.0.0",
+            "resolved": "https://registry.npmjs.org/enabled/-/enabled-2.0.0.tgz",
+            "integrity": "sha512-AKrN98kuwOzMIdAizXGI86UFBoo26CL21UM763y1h/GMSJ4/OHU9k2YlsmBpyScFo/wbLzWQJBMCW4+IO3/+OQ=="
+        },
         "node_modules/encoding-japanese": {
             "version": "2.1.0",
             "resolved": "https://registry.npmjs.org/encoding-japanese/-/encoding-japanese-2.1.0.tgz",
@@ -1845,6 +1937,24 @@
                 "fxparser": "src/cli/cli.js"
             }
         },
+        "node_modules/fecha": {
+            "version": "4.2.3",
+            "resolved": "https://registry.npmjs.org/fecha/-/fecha-4.2.3.tgz",
+            "integrity": "sha512-OP2IUU6HeYKJi3i0z4A19kHMQoLVs4Hc+DPqqxI2h/DPZHTm/vjsfC6P0b4jCMy14XizLBqvndQ+UilD7707Jw=="
+        },
+        "node_modules/file-stream-rotator": {
+            "version": "0.6.1",
+            "resolved": "https://registry.npmjs.org/file-stream-rotator/-/file-stream-rotator-0.6.1.tgz",
+            "integrity": "sha512-u+dBid4PvZw17PmDeRcNOtCP9CCK/9lRN2w+r1xIS7yOL9JFrIBKTvrYsxT4P0pGtThYTn++QS5ChHaUov3+zQ==",
+            "dependencies": {
+                "moment": "^2.29.1"
+            }
+        },
+        "node_modules/fn.name": {
+            "version": "1.1.0",
+            "resolved": "https://registry.npmjs.org/fn.name/-/fn.name-1.1.0.tgz",
+            "integrity": "sha512-GRnmB5gPyJpAhTQdSZTSp9uaPSvl09KoYcMQtsB9rQoOmzs9dH6ffeccH+Z+cv6P68Hu5bC6JjRh4Ah/mHSNRw=="
+        },
         "node_modules/follow-redirects": {
             "version": "1.15.9",
             "resolved": "https://registry.npmjs.org/follow-redirects/-/follow-redirects-1.15.9.tgz",
@@ -2062,6 +2172,11 @@
                 "url": "https://github.com/sponsors/ljharb"
             }
         },
+        "node_modules/is-arrayish": {
+            "version": "0.3.2",
+            "resolved": "https://registry.npmjs.org/is-arrayish/-/is-arrayish-0.3.2.tgz",
+            "integrity": "sha512-eVRqCvVlZbuw3GrM63ovNSNAeA1K16kaR/LRY/92w0zxQ5/1YzwblUX652i4Xs9RwAGjW9d9y6X88t8OaAJfWQ=="
+        },
         "node_modules/is-callable": {
             "version": "1.2.7",
             "resolved": "https://registry.npmjs.org/is-callable/-/is-callable-1.2.7.tgz",
@@ -2087,6 +2202,17 @@
                 "url": "https://github.com/sponsors/ljharb"
             }
         },
+        "node_modules/is-stream": {
+            "version": "2.0.1",
+            "resolved": "https://registry.npmjs.org/is-stream/-/is-stream-2.0.1.tgz",
+            "integrity": "sha512-hFoiJiTl63nn+kstHGBtewWSKnQLpyb155KHheA1l39uvtO9nWIop1p3udqPcUd/xbF1VLMO4n7OI6p7RbngDg==",
+            "engines": {
+                "node": ">=8"
+            },
+            "funding": {
+                "url": "https://github.com/sponsors/sindresorhus"
+            }
+        },
         "node_modules/is-typed-array": {
             "version": "1.1.13",
             "resolved": "https://registry.npmjs.org/is-typed-array/-/is-typed-array-1.1.13.tgz",
@@ -2114,6 +2240,11 @@
                 "node": ">= 0.6.0"
             }
         },
+        "node_modules/kuler": {
+            "version": "2.0.0",
+            "resolved": "https://registry.npmjs.org/kuler/-/kuler-2.0.0.tgz",
+            "integrity": "sha512-Xq9nH7KlWZmXAtodXDDRE7vs6DU1gTU8zYDHDiWLSip45Egwq3plLHzPn27NgvzL2r1LMPC1vdqh98sQxtqj4A=="
+        },
         "node_modules/leac": {
             "version": "0.6.0",
             "resolved": "https://registry.npmjs.org/leac/-/leac-0.6.0.tgz",
@@ -2151,6 +2282,22 @@
                 "uc.micro": "^2.0.0"
             }
         },
+        "node_modules/logform": {
+            "version": "2.7.0",
+            "resolved": "https://registry.npmjs.org/logform/-/logform-2.7.0.tgz",
+            "integrity": "sha512-TFYA4jnP7PVbmlBIfhlSe+WKxs9dklXMTEGcBCIvLhE/Tn3H6Gk1norupVW7m5Cnd4bLcr08AytbyV/xj7f/kQ==",
+            "dependencies": {
+                "@colors/colors": "1.6.0",
+                "@types/triple-beam": "^1.3.2",
+                "fecha": "^4.2.0",
+                "ms": "^2.1.1",
+                "safe-stable-stringify": "^2.3.1",
+                "triple-beam": "^1.3.0"
+            },
+            "engines": {
+                "node": ">= 12.0.0"
+            }
+        },
         "node_modules/mailparser": {
             "version": "3.7.1",
             "resolved": "https://registry.npmjs.org/mailparser/-/mailparser-3.7.1.tgz",
@@ -2226,6 +2373,24 @@
                 "node": ">= 0.6"
             }
         },
+        "node_modules/moment": {
+            "version": "2.30.1",
+            "resolved": "https://registry.npmjs.org/moment/-/moment-2.30.1.tgz",
+            "integrity": "sha512-uEmtNhbDOrWPFS+hdjFCBfy9f2YoyzRpwcl+DqpC6taX21FzsTLQVbMV/W7PzNSX6x/bhC1zA3c2UQ5NzH6how==",
+            "engines": {
+                "node": "*"
+            }
+        },
+        "node_modules/ms": {
+            "version": "2.1.3",
+            "resolved": "https://registry.npmjs.org/ms/-/ms-2.1.3.tgz",
+            "integrity": "sha512-6FlzubTLZG3J2a/NVCAleEhjzq5oxgHyaCU9yYXvcLsvoVaHJq/s5xXI6/XXP6tz7R9xAOtHnSO/tXtF3WRTlA=="
+        },
+        "node_modules/node-eta": {
+            "version": "0.9.0",
+            "resolved": "https://registry.npmjs.org/node-eta/-/node-eta-0.9.0.tgz",
+            "integrity": "sha512-mTCTZk29tmX1OGfVkPt63H3c3VqXrI2Kvua98S7iUIB/Gbp0MNw05YtUomxQIxnnKMyRIIuY9izPcFixzhSBrA=="
+        },
         "node_modules/nodemailer": {
             "version": "6.9.13",
             "resolved": "https://registry.npmjs.org/nodemailer/-/nodemailer-6.9.13.tgz",
@@ -2234,6 +2399,22 @@
                 "node": ">=6.0.0"
             }
         },
+        "node_modules/object-hash": {
+            "version": "2.2.0",
+            "resolved": "https://registry.npmjs.org/object-hash/-/object-hash-2.2.0.tgz",
+            "integrity": "sha512-gScRMn0bS5fH+IuwyIFgnh9zBdo4DV+6GhygmWM9HyNJSgS0hScp1f5vjtm7oIIOiT9trXrShAkLFSc2IqKNgw==",
+            "engines": {
+                "node": ">= 6"
+            }
+        },
+        "node_modules/one-time": {
+            "version": "1.0.0",
+            "resolved": "https://registry.npmjs.org/one-time/-/one-time-1.0.0.tgz",
+            "integrity": "sha512-5DXOiRKwuSEcQ/l0kGCF6Q3jcADFv5tSmRaJck/OqkVFcOzutB134KRSfF0xDrL39MNnqxbHBbUUcjZIhTgb2g==",
+            "dependencies": {
+                "fn.name": "1.x.x"
+            }
+        },
         "node_modules/parseley": {
             "version": "0.12.1",
             "resolved": "https://registry.npmjs.org/parseley/-/parseley-0.12.1.tgz",
@@ -2321,6 +2502,14 @@
                 }
             ]
         },
+        "node_modules/safe-stable-stringify": {
+            "version": "2.5.0",
+            "resolved": "https://registry.npmjs.org/safe-stable-stringify/-/safe-stable-stringify-2.5.0.tgz",
+            "integrity": "sha512-b3rppTKm9T+PsVCBEOUR46GWI7fdOs00VKZ1+9c1EWDaDMvjQc6tUwuFyIprgGgTcWoVHSKrU8H31ZHA2e0RHA==",
+            "engines": {
+                "node": ">=10"
+            }
+        },
         "node_modules/safer-buffer": {
             "version": "2.1.2",
             "resolved": "https://registry.npmjs.org/safer-buffer/-/safer-buffer-2.1.2.tgz",
@@ -2358,6 +2547,14 @@
                 "node": ">= 0.4"
             }
         },
+        "node_modules/simple-swizzle": {
+            "version": "0.2.2",
+            "resolved": "https://registry.npmjs.org/simple-swizzle/-/simple-swizzle-0.2.2.tgz",
+            "integrity": "sha512-JA//kQgZtbuY83m+xT+tXJkmJncGMTFT+C+g2h2R9uxkYIrE2yy9sgmcLhCnw57/WSD+Eh3J97FPEDFnbXnDUg==",
+            "dependencies": {
+                "is-arrayish": "^0.3.1"
+            }
+        },
         "node_modules/smtp-server": {
             "version": "3.13.5",
             "resolved": "https://registry.npmjs.org/smtp-server/-/smtp-server-3.13.5.tgz",
@@ -2380,6 +2577,14 @@
                 "node": ">=6.0.0"
             }
         },
+        "node_modules/stack-trace": {
+            "version": "0.0.10",
+            "resolved": "https://registry.npmjs.org/stack-trace/-/stack-trace-0.0.10.tgz",
+            "integrity": "sha512-KGzahc7puUKkzyMt+IqAep+TVNbKP+k2Lmwhub39m1AsTSkaDutx56aDCo+HLDzf/D26BIHTJWNiTG1KAJiQCg==",
+            "engines": {
+                "node": "*"
+            }
+        },
         "node_modules/stream-browserify": {
             "version": "3.0.0",
             "resolved": "https://registry.npmjs.org/stream-browserify/-/stream-browserify-3.0.0.tgz",
@@ -2402,6 +2607,11 @@
             "resolved": "https://registry.npmjs.org/strnum/-/strnum-1.0.5.tgz",
             "integrity": "sha512-J8bbNyKKXl5qYcR36TIO8W3mVGVHrmmxsd5PAItGkmyzwJvybiw2IVq5nqd0i4LSNSkB/sx9VHllbfFdr9k1JA=="
         },
+        "node_modules/text-hex": {
+            "version": "1.0.0",
+            "resolved": "https://registry.npmjs.org/text-hex/-/text-hex-1.0.0.tgz",
+            "integrity": "sha512-uuVGNWzgJ4yhRaNSiubPY7OjISw4sw4E5Uv0wbjp+OzcbmVU/rsT8ujgcXJhn9ypzsgr5vlzpPqP+MBBKcGvbg=="
+        },
         "node_modules/tlds": {
             "version": "1.252.0",
             "resolved": "https://registry.npmjs.org/tlds/-/tlds-1.252.0.tgz",
@@ -2410,6 +2620,14 @@
                 "tlds": "bin.js"
             }
         },
+        "node_modules/triple-beam": {
+            "version": "1.4.1",
+            "resolved": "https://registry.npmjs.org/triple-beam/-/triple-beam-1.4.1.tgz",
+            "integrity": "sha512-aZbgViZrg1QNcG+LULa7nhZpJTZSLm/mXnHXnbAbjmN5aSa0y7V+wvv6+4WaBtpISJzThKy+PIPxc1Nq1EJ9mg==",
+            "engines": {
+                "node": ">= 14.0.0"
+            }
+        },
         "node_modules/tslib": {
             "version": "2.7.0",
             "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.7.0.tgz",
@@ -2476,6 +2694,57 @@
                 "url": "https://github.com/sponsors/ljharb"
             }
         },
+        "node_modules/winston": {
+            "version": "3.17.0",
+            "resolved": "https://registry.npmjs.org/winston/-/winston-3.17.0.tgz",
+            "integrity": "sha512-DLiFIXYC5fMPxaRg832S6F5mJYvePtmO5G9v9IgUFPhXm9/GkXarH/TUrBAVzhTCzAj9anE/+GjrgXp/54nOgw==",
+            "dependencies": {
+                "@colors/colors": "^1.6.0",
+                "@dabh/diagnostics": "^2.0.2",
+                "async": "^3.2.3",
+                "is-stream": "^2.0.0",
+                "logform": "^2.7.0",
+                "one-time": "^1.0.0",
+                "readable-stream": "^3.4.0",
+                "safe-stable-stringify": "^2.3.1",
+                "stack-trace": "0.0.x",
+                "triple-beam": "^1.3.0",
+                "winston-transport": "^4.9.0"
+            },
+            "engines": {
+                "node": ">= 12.0.0"
+            }
+        },
+        "node_modules/winston-daily-rotate-file": {
+            "version": "4.7.1",
+            "resolved": "https://registry.npmjs.org/winston-daily-rotate-file/-/winston-daily-rotate-file-4.7.1.tgz",
+            "integrity": "sha512-7LGPiYGBPNyGHLn9z33i96zx/bd71pjBn9tqQzO3I4Tayv94WPmBNwKC7CO1wPHdP9uvu+Md/1nr6VSH9h0iaA==",
+            "dependencies": {
+                "file-stream-rotator": "^0.6.1",
+                "object-hash": "^2.0.1",
+                "triple-beam": "^1.3.0",
+                "winston-transport": "^4.4.0"
+            },
+            "engines": {
+                "node": ">=8"
+            },
+            "peerDependencies": {
+                "winston": "^3"
+            }
+        },
+        "node_modules/winston-transport": {
+            "version": "4.9.0",
+            "resolved": "https://registry.npmjs.org/winston-transport/-/winston-transport-4.9.0.tgz",
+            "integrity": "sha512-8drMJ4rkgaPo1Me4zD/3WLfI/zPdA9o2IipKODunnGDcuqbHwjsbB79ylv04LCGGzU0xQ6vTznOMpQGaLhhm6A==",
+            "dependencies": {
+                "logform": "^2.7.0",
+                "readable-stream": "^3.6.2",
+                "triple-beam": "^1.3.0"
+            },
+            "engines": {
+                "node": ">= 12.0.0"
+            }
+        },
         "node_modules/xml2js": {
             "version": "0.6.2",
             "resolved": "https://registry.npmjs.org/xml2js/-/xml2js-0.6.2.tgz",

server.js

@@ -1,3 +1,6 @@
+const crypto = require('crypto');
+const fs = require('fs');
+const path = require('path');
 const SMTPServer = require('smtp-server').SMTPServer;
 const config = require('./config');
 const { parseEmail } = require('./services/emailParser');
@@ -14,9 +17,10 @@ const logger = winston.createLogger({
     winston.format.json()
   ),
   transports: [
-    new winston.transports.Console(),
+    // Supervisor captures stdout/stderr. A regular file avoids EPIPE loops
+    // when Supervisor rotates its child logs.
     new winston.transports.DailyRotateFile({
-      filename: 'logs/application-%DATE%.log',
+      filename: path.join(config.LOG_DIR, 'application-%DATE%.log'),
       datePattern: 'YYYY-MM-DD',
       zippedArchive: true,
       maxSize: '20m',
@@ -26,102 +30,343 @@ const logger = winston.createLogger({
 });
 
 function validateConfig() {
-  const requiredKeys = ['PORT', 'SMTP_SECURE', 'WEBHOOK_URL', 'WEBHOOK_CONCURRENCY'];
+  if (!config.WEBHOOK_URL) {
-  for (const key of requiredKeys) {
+    throw new Error('Missing required configuration: WEBHOOK_URL');
-    if (!(key in config)) {
+  }
-      throw new Error(`Missing required configuration: ${key}`);
+  if (!/^https?:\/\//i.test(config.WEBHOOK_URL)) {
-    }
+    throw new Error('WEBHOOK_URL must use http:// or https://');
+  }
+  if (!Number.isInteger(config.PORT) || config.PORT < 1 || config.PORT > 65535) {
+    throw new Error('PORT must be an integer between 1 and 65535');
+  }
+  if (!Number.isInteger(config.MAX_FILE_SIZE) || config.MAX_FILE_SIZE < 0) {
+    throw new Error('MAX_FILE_SIZE must be a non-negative integer');
+  }
+  if (!Number.isInteger(config.MAX_MESSAGE_SIZE) || config.MAX_MESSAGE_SIZE < 0) {
+    throw new Error('MAX_MESSAGE_SIZE must be a non-negative integer');
+  }
+  if (!Number.isInteger(config.MAX_SMTP_CLIENTS) || config.MAX_SMTP_CLIENTS < 1) {
+    throw new Error('MAX_SMTP_CLIENTS must be a positive integer');
+  }
+  if (!Number.isInteger(config.WEBHOOK_CONCURRENCY) || config.WEBHOOK_CONCURRENCY < 1) {
+    throw new Error('WEBHOOK_CONCURRENCY must be a positive integer');
+  }
+  if (!Number.isInteger(config.WEBHOOK_QUEUE_RETRIES) || config.WEBHOOK_QUEUE_RETRIES < 0) {
+    throw new Error('WEBHOOK_QUEUE_RETRIES must be a non-negative integer');
+  }
+  if (!Number.isInteger(config.WEBHOOK_QUEUE_RETRY_DELAY) || config.WEBHOOK_QUEUE_RETRY_DELAY < 1000) {
+    throw new Error('WEBHOOK_QUEUE_RETRY_DELAY must be at least 1000 milliseconds');
+  }
+  if (!Number.isInteger(config.WEBHOOK_QUEUE_TIMEOUT) || config.WEBHOOK_QUEUE_TIMEOUT < 1000) {
+    throw new Error('WEBHOOK_QUEUE_TIMEOUT must be at least 1000 milliseconds');
+  }
+  if (config.SMTP_SECURE && (!config.TLS_KEY_PATH || !config.TLS_CERT_PATH)) {
+    throw new Error('SMTP_SECURE=true requires TLS_KEY_PATH and TLS_CERT_PATH');
   }
 }
 
-const webhookQueue = new Queue(async function (parsed, cb) {
-  const maxRetries = 3;
-  let retries = 0;
-
-  const attemptWebhook = async () => {
-    try {
-      await sendToWebhook(parsed);
-      logger.info('Successfully sent to webhook');
-      cb(null);
-    } catch (error) {
-      logger.error('Webhook error:', { message: error.message, stack: error.stack });
-      if (error.response) {
-        logger.error('Webhook response error:', { 
-          status: error.response.status, 
-          data: error.response.data 
-        });
-      }
-      if (retries < maxRetries) {
-        retries++;
-        logger.info(`Retrying webhook (attempt ${retries}/${maxRetries})`);
-        setTimeout(attemptWebhook, 1000 * retries);
-      } else {
-        cb(error);
-      }
-    }
-  };
-
-  attemptWebhook();
-}, { concurrent: config.WEBHOOK_CONCURRENCY || 5 });
-
-const server = new SMTPServer({
-  onData(stream, session, callback) {
-    parseEmail(stream)
-      .then(parsed => {
-        webhookQueue.push(parsed);
-        logger.info('Email added to queue', { queueSize: webhookQueue.getStats().total });
-        callback();
-      })
-      .catch(error => {
-        logger.error('Parsing error:', { message: error.message, stack: error.stack });
-        callback(new Error('Failed to parse email'));
-      });
-  },
-  onError(error) {
-    logger.error('SMTP server error:', { message: error.message, stack: error.stack });
-  },
-  disabledCommands: ['AUTH'],
-  secure: config.SMTP_SECURE
-});
-
-server.listen(config.PORT, '0.0.0.0', err => {
-  if (err) {
-    logger.error('Failed to start SMTP server:', { message: err.message, stack: err.stack });
-    process.exit(1);
-  }
-  logger.info(`SMTP server listening on port ${config.PORT} on all interfaces`);
-});
-
-function gracefulShutdown(reason) {
-  logger.info(`Shutting down: ${reason}`);
-  server.close(() => {
-    logger.info('Server closed. Exiting process.');
-    process.exit(0);
-  });
-}
-
-process.on('uncaughtException', (err) => {
-  logger.error('Uncaught exception:', { message: err.message, stack: err.stack });
-  gracefulShutdown('Uncaught exception');
-});
-
-process.on('unhandledRejection', (reason, promise) => {
-  logger.error('Unhandled Rejection:', { reason: reason, promise: promise });
-  gracefulShutdown('Unhandled rejection');
-});
-
-process.on('SIGTERM', () => {
-  gracefulShutdown('SIGTERM signal received');
-});
-
-process.on('SIGINT', () => {
-  gracefulShutdown('SIGINT signal received');
-});
-
-// Add configuration validation at startup
 try {
   validateConfig();
 } catch (error) {
   logger.error('Configuration error:', { message: error.message });
   process.exit(1);
-}
+}
+
+const pendingDir = path.join(config.SPOOL_DIR, 'pending');
+const failedDir = path.join(config.SPOOL_DIR, 'failed');
+let shuttingDown = false;
+let spoolScanTimer = null;
+let activeJobs = 0;
+const activeJobWaiters = new Set();
+const enqueuedJobIds = new Set();
+
+try {
+  fs.mkdirSync(pendingDir, { recursive: true, mode: 0o700 });
+  fs.mkdirSync(failedDir, { recursive: true, mode: 0o700 });
+} catch (error) {
+  logger.error('Failed to initialize spool directories:', {
+    message: error.message,
+    stack: error.stack
+  });
+  process.exit(1);
+}
+
+function notifyActiveJobWaiters() {
+  if (activeJobs !== 0) return;
+  for (const waiter of activeJobWaiters) waiter();
+  activeJobWaiters.clear();
+}
+
+function waitForActiveJobs(timeout) {
+  if (activeJobs === 0) return Promise.resolve();
+
+  return new Promise(resolve => {
+    let timer;
+    const onDone = () => {
+      clearTimeout(timer);
+      activeJobWaiters.delete(onDone);
+      resolve();
+    };
+
+    timer = setTimeout(onDone, timeout);
+    activeJobWaiters.add(onDone);
+  });
+}
+
+function delay(milliseconds) {
+  return new Promise(resolve => setTimeout(resolve, milliseconds));
+}
+
+function logWebhookError(error) {
+  const message = error instanceof Error ? error.message : String(error);
+  const stack = error instanceof Error ? error.stack : undefined;
+  logger.error('Webhook error:', { message, stack });
+
+  if (error && error.response) {
+    let data = error.response.data;
+    if (typeof data === 'string') data = data.slice(0, 500);
+    logger.error('Webhook response error:', {
+      status: error.response.status,
+      data
+    });
+  }
+}
+
+async function sendWithRetry(parsed) {
+  const maxRetries = 3;
+  let retries = 0;
+
+  while (true) {
+    try {
+      await sendToWebhook(parsed);
+      return;
+    } catch (error) {
+      logWebhookError(error);
+      if (retries >= maxRetries) throw error;
+
+      retries++;
+      logger.info(`Retrying webhook (attempt ${retries}/${maxRetries})`);
+      await delay(1000 * retries);
+    }
+  }
+}
+
+async function persistEmail(parsed) {
+  const id = `${Date.now()}-${process.pid}-${crypto.randomUUID()}`;
+  const filePath = path.join(pendingDir, `${id}.json`);
+  const temporaryPath = `${filePath}.tmp`;
+
+  let fileHandle;
+  try {
+    fileHandle = await fs.promises.open(temporaryPath, 'w', 0o600);
+    await fileHandle.writeFile(JSON.stringify(parsed), 'utf8');
+    await fileHandle.sync();
+    await fileHandle.close();
+    fileHandle = undefined;
+    await fs.promises.rename(temporaryPath, filePath);
+    return { id, filePath };
+  } catch (error) {
+    if (fileHandle) {
+      await fileHandle.close().catch(() => {});
+    }
+    await fs.promises.unlink(temporaryPath).catch(() => {});
+    throw error;
+  }
+}
+
+async function quarantineFile(filePath) {
+  const target = path.join(
+    failedDir,
+    `${path.basename(filePath)}.${Date.now()}.failed`
+  );
+  await fs.promises.rename(filePath, target);
+  return target;
+}
+
+async function processWebhookJob(job, cb) {
+  activeJobs++;
+
+  try {
+    let parsed;
+    try {
+      parsed = JSON.parse(await fs.promises.readFile(job.filePath, 'utf8'));
+    } catch (error) {
+      if (error.code === 'ENOENT') {
+        logger.warn('Spool job disappeared before processing', { jobId: job.id });
+        cb(null);
+        return;
+      }
+
+      try {
+        const failedPath = await quarantineFile(job.filePath);
+        logger.error('Invalid spool job moved to failed spool', {
+          jobId: job.id,
+          failedPath,
+          message: error.message
+        });
+        cb(null);
+      } catch (quarantineError) {
+        cb(quarantineError);
+      }
+      return;
+    }
+
+    await sendWithRetry(parsed);
+    await fs.promises.unlink(job.filePath);
+    logger.info('Successfully sent to webhook', { jobId: job.id });
+    cb(null);
+  } catch (error) {
+    logWebhookError(error);
+    cb(error);
+  } finally {
+    activeJobs--;
+    notifyActiveJobWaiters();
+  }
+}
+
+const webhookQueue = new Queue(processWebhookJob, {
+  concurrent: config.WEBHOOK_CONCURRENCY,
+  maxRetries: config.WEBHOOK_QUEUE_RETRIES,
+  retryDelay: config.WEBHOOK_QUEUE_RETRY_DELAY,
+  maxTimeout: config.WEBHOOK_QUEUE_TIMEOUT
+});
+
+webhookQueue.on('error', error => {
+  logger.error('Webhook queue error:', { message: error.message, stack: error.stack });
+});
+
+webhookQueue.on('task_failed', (jobId, error) => {
+  logger.error('Webhook queue task exhausted retries:', {
+    jobId,
+    message: error && error.message ? error.message : String(error)
+  });
+});
+
+function enqueueSpoolFile(filePath) {
+  const id = path.basename(filePath, '.json');
+  if (enqueuedJobIds.has(id)) return;
+
+  enqueuedJobIds.add(id);
+  const ticket = webhookQueue.push({ id, filePath });
+  ticket.once('finish', () => enqueuedJobIds.delete(id));
+  ticket.once('failed', () => enqueuedJobIds.delete(id));
+}
+
+async function scanSpool() {
+  if (shuttingDown) return;
+
+  try {
+    const entries = await fs.promises.readdir(pendingDir, { withFileTypes: true });
+    for (const entry of entries) {
+      if (entry.isFile() && entry.name.endsWith('.json')) {
+        enqueueSpoolFile(path.join(pendingDir, entry.name));
+      }
+    }
+  } catch (error) {
+    logger.error('Failed to scan spool:', { message: error.message, stack: error.stack });
+  }
+}
+
+const smtpOptions = {
+  maxClients: config.MAX_SMTP_CLIENTS,
+  socketTimeout: config.SMTP_SOCKET_TIMEOUT,
+  closeTimeout: config.SMTP_CLOSE_TIMEOUT,
+  size: config.MAX_MESSAGE_SIZE || undefined,
+  onConnect(session, callback) {
+    if (
+      config.SMTP_ALLOWED_IPS.length > 0 &&
+      !config.SMTP_ALLOWED_IPS.includes(session.remoteAddress)
+    ) {
+      const error = new Error('Connection not allowed');
+      error.responseCode = 421;
+      callback(error);
+      return;
+    }
+    callback();
+  },
+  onData(stream, session, callback) {
+    parseEmail(stream)
+      .then(async parsed => {
+        const job = await persistEmail(parsed);
+        enqueueSpoolFile(job.filePath);
+        logger.info('Email persisted and added to queue', {
+          jobId: job.id,
+          queued: webhookQueue.length
+        });
+        callback();
+      })
+      .catch(error => {
+        logger.error('Parsing or persistence error:', {
+          message: error.message,
+          stack: error.stack
+        });
+        callback(new Error('Failed to persist email'));
+      });
+  },
+  disabledCommands: ['AUTH'],
+  secure: config.SMTP_SECURE
+};
+
+if (config.SMTP_SECURE) {
+  smtpOptions.key = fs.readFileSync(config.TLS_KEY_PATH);
+  smtpOptions.cert = fs.readFileSync(config.TLS_CERT_PATH);
+}
+
+const server = new SMTPServer(smtpOptions);
+
+let serverReady = false;
+server.on('error', error => {
+  logger.error('SMTP server error:', { message: error.message, stack: error.stack });
+  if (!serverReady) {
+    // Let the file transport flush the startup error before exiting. Since the
+    // listener never came up, there are no active handles keeping the process
+    // alive; the non-zero exit code still lets Supervisor restart it.
+    process.exitCode = 1;
+  }
+});
+
+function gracefulShutdown(reason) {
+  if (shuttingDown) return;
+  shuttingDown = true;
+  logger.info(`Shutting down: ${reason}`);
+  clearInterval(spoolScanTimer);
+  webhookQueue.pause();
+
+  const cleanShutdown = reason === 'SIGTERM signal received' || reason === 'SIGINT signal received';
+  const exitCode = cleanShutdown ? 0 : 1;
+  const shutdownDeadline = setTimeout(() => {
+    logger.error('Shutdown timeout reached; exiting with pending spool jobs preserved');
+    process.exit(exitCode);
+  }, 15000);
+
+  server.close(async () => {
+    await waitForActiveJobs(10000);
+    clearTimeout(shutdownDeadline);
+    logger.info('Server closed. Exiting process.');
+    process.exit(exitCode);
+  });
+}
+
+process.on('uncaughtException', error => {
+  logger.error('Uncaught exception:', { message: error.message, stack: error.stack });
+  gracefulShutdown('Uncaught exception');
+});
+
+process.on('unhandledRejection', reason => {
+  const error = reason instanceof Error
+    ? { message: reason.message, stack: reason.stack }
+    : { message: String(reason) };
+  logger.error('Unhandled Rejection:', error);
+  gracefulShutdown('Unhandled rejection');
+});
+
+process.on('SIGTERM', () => gracefulShutdown('SIGTERM signal received'));
+process.on('SIGINT', () => gracefulShutdown('SIGINT signal received'));
+
+server.listen(config.PORT, '0.0.0.0', () => {
+  serverReady = true;
+  logger.info(`SMTP server listening on port ${config.PORT} on all interfaces`);
+  void scanSpool();
+  spoolScanTimer = setInterval(() => void scanSpool(), 60 * 1000);
+  spoolScanTimer.unref();
+});