Capture and handle errors during stringify. (#544)

Author: purple4reina

src/utils/tag-object.spec.ts

@@ -99,6 +99,23 @@ describe("tagObject", () => {
       ["function.request.vals.1", '{"thingTwo":2}'],
     ]);
   });
+  it("handles circular objects", () => {
+    const span = {
+      setTag,
+    };
+    var obj = {
+      key: "value",
+      array: Array<any>(),
+    };
+    obj.array.push(obj);
+    tagObject(span, "lambda_payload", { request: obj }, 1);
+    expect(setTag.mock.calls).toEqual([
+      ["lambda_payload.request.key", "value"],
+      ["lambda_payload.request.array.0.key", "value"],
+      ["lambda_payload.request.array.0.array.0.key", "value"],
+      ["lambda_payload.request.array.0.array.0.array.0.key", "value"],
+    ]);
+  });
   it("redacts common secret keys", () => {
     const span = {
       setTag,

src/utils/tag-object.ts

@@ -1,3 +1,5 @@
+import { logDebug } from "./log";
+
 const redactableKeys = ["authorization", "x-authorization", "password", "token"];
 
 export function tagObject(currentSpan: any, key: string, obj: any, depth = 0, maxDepth = 10): any {
@@ -6,7 +8,13 @@ export function tagObject(currentSpan: any, key: string, obj: any, depth = 0, ma
     return currentSpan.setTag(key, obj);
   }
   if (depth >= maxDepth) {
-    const strOrUndefined = JSON.stringify(obj);
+    let strOrUndefined;
+    try {
+      strOrUndefined = JSON.stringify(obj);
+    } catch (e) {
+      logDebug(`Unable to stringify object for tagging: ${e}`);
+      return;
+    }
     if (typeof strOrUndefined === "undefined") return;
     return currentSpan.setTag(key, redactVal(key, strOrUndefined.substring(0, 5000)));
   }