feat: override status code with thrown error message (#592)

* feat: parse relaxed json and extracted from message

* fix: removed json5 direct dependency

* feat: ff env var & generalized matching

README.md

@@ -790,6 +790,7 @@ Advanced options can be configured as a parameter to the init() method or as env
 |batchSize          |EPSAGON_BATCH_SIZE         |Integer|`5 `         |The traces' batch size, when batch mode is activated                               |
 |decodeHTTP         |EPSAGON_DECODE_HTTP        |Boolean|`true`       |Whether to decode and decompress HTTP responses into the payload                   |
 |httpErrorStatusCode|EPSAGON_HTTP_ERR_CODE      |Integer|`400`        |The minimum number of an HTTP response status code to treat as an error            |
+|-                  |EPSAGON_ALLOW_ERR_MESSAGE_STATUS|Boolean|`true`  |Whether to override `http.status_code` with a Status Code found in a raised Error's Message|
 |-                  |EPSAGON_PROPAGATE_LAMBDA_ID|Boolean|`false`      |Insert Lambda request ID into the response payload                                 |
 |-                  |DISABLE_EPSAGON_PATCH      |Boolean|`false`      |Disable the library patching (instrumentation)                                     |
 |isConsolePatched   |EPSAGON_PATCH_CONSOLE      |Boolean|`false`      |Enable console module patching (instrumentation) for labelling                     |

src/config.js

@@ -85,6 +85,7 @@ const config = {
     sendTimeout: (Number(process.env.EPSAGON_SEND_TIMEOUT_SEC) || DEFAULT_TIMEOUT_SEC) * 1000.0,
     decodeHTTP: (process.env.EPSAGON_DECODE_HTTP || 'TRUE').toUpperCase() === 'TRUE',
     disableHttpResponseBodyCapture: (process.env.EPSAGON_DISABLE_HTTP_RESPONSE || '').toUpperCase() === 'TRUE',
+    allowErrMessageStatus: (process.env.EPSAGON_ALLOW_ERR_MESSAGE_STATUS || '').toUpperCase() === 'TRUE',
     loggingTracingEnabled: (process.env.EPSAGON_LOGGING_TRACING_ENABLED || (!utils.isLambdaEnv).toString()).toUpperCase() === 'TRUE',
     sendBatch: (process.env.EPSAGON_SEND_BATCH || (!utils.isLambdaEnv).toString()).toUpperCase() === 'TRUE',
     batchSize: (Number(process.env.EPSAGON_BATCH_SIZE) || consts.DEFAULT_BATCH_SIZE),

src/utils.js

@@ -204,6 +204,24 @@ function distinct(arr) {
     return [...new Set(arr)];
 }
 
+/**
+ * Attempt to extract an HTTP Status Code from a String.
+ * Matches and returns only 3-digit numbers in range 2XX-5XX.
+ * @param {String} message A String containing a Status Code.
+ * @return {Number} extracted Status Code. If not found -> 0, the only falsy Number.
+ */
+function extractStatusCode(message) {
+    // matches a [Non-Digit], [2xx - 5xx], and a [Non-Digit]. globally & multiline.
+    //              \D        ([2-5]\d{2})          \D            /g         m
+    const statusCodeMatch = /\D([2-5]\d{2})\D/gm;
+    const statusCodes = message
+        .match(statusCodeMatch)
+        .map(m => m.replace(statusCodeMatch, '$1'));
+    if (statusCodes && statusCodes.length) {
+        return Number(statusCodes[0]);
+    }
+    return 0;
+}
 
 module.exports.createTimestampFromTime = createTimestampFromTime;
 module.exports.createTimestamp = createTimestamp;
@@ -220,3 +238,4 @@ module.exports.isLambdaEnv = isLambdaEnv;
 module.exports.getValueIfExist = getValueIfExist;
 module.exports.truncateMessage = truncateMessage;
 module.exports.distinct = distinct;
+module.exports.extractStatusCode = extractStatusCode;

src/wrappers/lambda.js

@@ -162,6 +162,7 @@ function baseLambdaWrapper(
                 return Promise.resolve();
             }
             callbackCalled = true;
+            const config = getConfig();
             if (error) {
                 // not catching false here, but that seems OK
                 let reportedError = error;
@@ -178,7 +179,15 @@ function baseLambdaWrapper(
                         message: errorMessage,
                     };
                 }
-
+                // Override status code with Error message
+                if (config.allowErrMessageStatus) {
+                    const errStatusCode = utils.extractStatusCode(reportedError.message);
+                    if (errStatusCode) {
+                        eventInterface.addToMetadata(runner, {
+                            status_code: errStatusCode,
+                        });
+                    }
+                }
                 // Setting this error only if there is no existing error already
                 if (!runner.getException()) {
                     utils.debugLog('Setting exception from handleUserExecutionDone');
@@ -190,7 +199,6 @@ function baseLambdaWrapper(
             if (statusCode) {
                 eventInterface.addToMetadata(runner, { status_code: statusCode });
             }
-            const config = getConfig();
             if (error === null && !config.metadataOnly && config.addReturnValue) {
                 try {
                     // Taken from AWS Lambda runtime