Allow functions as backtrace matchers

packages/javascript/.changesets/allow-functions-as-backtrace-matchers.md

@@ -0,0 +1,19 @@
+---
+bump: patch
+type: add
+---
+
+Allow functions as backtrace matchers. Alongside regular expressions, you can also provide custom functions to match and replace paths in the backtrace:
+
+```javascript
+const appsignal = new Appsignal({
+  // ...
+  matchBacktracePaths: [(path) => {
+    if (path.indexOf("/bundle/") !== -1) {
+      return "bundle.js"
+    }
+  }]
+})
+```
+
+The function must take a backtrace line path as an argument. When the function returns a non-empty string, the string will be used as the path for that backtrace line. Otherwise, the path will be left unchanged.

packages/javascript/src/__tests__/index.test.ts

@@ -97,13 +97,17 @@ describe("Appsignal", () => {
       appsignal = new Appsignal({
         key: "TESTKEY",
         namespace: "test",
-        matchBacktracePaths: [/here(.*)/g]
+        matchBacktracePaths: [
+          /here(.*)/g,
+          path => (path.indexOf("some") !== -1 ? "some.js" : undefined)
+        ]
       })
 
       const error = new Error("test error")
       error.stack = [
         "Error: test error",
-        "    at Foo (http://localhost:8080/here/istheapp.js:13:10)"
+        "    at Foo (http://localhost:8080/here/istheapp.js:13:10)",
+        "    at Bar (http://localhost:8080/some/thingelse.js:13:10)"
       ].join("\n")
 
       appsignal.send(error)
@@ -112,10 +116,11 @@ describe("Appsignal", () => {
 
       expect(firstPayload.error.backtrace).toEqual([
         "Error: test error",
-        "    at Foo (/istheapp.js:13:10)"
+        "    at Foo (/istheapp.js:13:10)",
+        "    at Bar (some.js:13:10)"
       ])
 
-      expect(firstPayload.environment.backtrace_paths_matched).toEqual("1")
+      expect(firstPayload.environment.backtrace_paths_matched).toEqual("2")
 
       // As the regex used has the `g` flag, it would
       // remember the last matched position and fail to match again:
@@ -124,7 +129,7 @@ describe("Appsignal", () => {
       appsignal.send(error)
 
       const secondPayload = pushMockCall(1)
-      expect(secondPayload.environment.backtrace_paths_matched).toEqual("1")
+      expect(secondPayload.environment.backtrace_paths_matched).toEqual("2")
     })
   })
 

packages/javascript/src/__tests__/span.test.ts

@@ -1,4 +1,4 @@
-import { Span } from "../span"
+import { Span, toBacktraceMatcher } from "../span"
 
 describe("Span", () => {
   let span: Span
@@ -71,7 +71,9 @@ describe("Span", () => {
       ].join("\n")
 
       span.setError(error)
-      span.cleanBacktracePath([new RegExp("/assets/(app/.*)$")])
+      span.cleanBacktracePath(
+        [new RegExp("/assets/(app/.*)$")].map(toBacktraceMatcher)
+      )
 
       const backtrace = span.serialize().error.backtrace
       expect(backtrace).toEqual([
@@ -97,7 +99,9 @@ describe("Span", () => {
       ].join("\n")
 
       span.setError(error)
-      span.cleanBacktracePath([new RegExp("/assets/(app/.*)$")])
+      span.cleanBacktracePath(
+        [new RegExp("/assets/(app/.*)$")].map(toBacktraceMatcher)
+      )
 
       const backtrace = span.serialize().error.backtrace
       expect(backtrace).toEqual([
@@ -123,9 +127,11 @@ describe("Span", () => {
       ].join("\n")
 
       span.setError(error)
-      span.cleanBacktracePath([
-        new RegExp(".*/(assets/)(?:[0-9a-f]{16}/)?(app/.*)$")
-      ])
+      span.cleanBacktracePath(
+        [new RegExp(".*/(assets/)(?:[0-9a-f]{16}/)?(app/.*)$")].map(
+          toBacktraceMatcher
+        )
+      )
 
       const backtrace = span.serialize().error.backtrace
       expect(backtrace).toEqual([
@@ -149,14 +155,16 @@ describe("Span", () => {
       ].join("\n")
 
       span.setError(error)
-      span.cleanBacktracePath([
-        // This can only match `Bar`.
-        new RegExp("/assets/[0-9a-f]{16}/(.*)$"),
-
-        // This can match both `Foo` and `Bar`, but should only
-        // match `Foo` because the previous matcher takes precedence.
-        new RegExp("/assets/(.*)$")
-      ])
+      span.cleanBacktracePath(
+        [
+          // This can only match `Bar`.
+          new RegExp("/assets/[0-9a-f]{16}/(.*)$"),
+
+          // This can match both `Foo` and `Bar`, but should only
+          // match `Foo` because the previous matcher takes precedence.
+          new RegExp("/assets/(.*)$")
+        ].map(toBacktraceMatcher)
+      )
 
       const backtrace = span.serialize().error.backtrace
       expect(backtrace).toEqual([
@@ -181,7 +189,7 @@ describe("Span", () => {
       // empty string.
       //
       // This should result in the line not being modified.
-      span.cleanBacktracePath([new RegExp(".*")])
+      span.cleanBacktracePath([new RegExp(".*")].map(toBacktraceMatcher))
 
       const backtrace = span.serialize().error.backtrace
       expect(backtrace).toEqual([
@@ -203,7 +211,7 @@ describe("Span", () => {
       // empty string.
       //
       // This should result in the line not being modified.
-      span.cleanBacktracePath([new RegExp(".*(z*)$")])
+      span.cleanBacktracePath([new RegExp(".*(z*)$")].map(toBacktraceMatcher))
 
       const backtrace = span.serialize().error.backtrace
       expect(backtrace).toEqual([
@@ -220,7 +228,9 @@ describe("Span", () => {
       ].join("\n")
 
       span.setError(error)
-      span.cleanBacktracePath([new RegExp("^pancakes/(.*)$")])
+      span.cleanBacktracePath(
+        [new RegExp("^pancakes/(.*)$")].map(toBacktraceMatcher)
+      )
 
       const backtrace = span.serialize().error.backtrace
       expect(backtrace).toEqual([
@@ -229,6 +239,32 @@ describe("Span", () => {
 
       expect(span.serialize().environment).toBeUndefined()
     })
+
+    it("can be used with custom backtrace matcher functions", () => {
+      const error = new Error("test error")
+      error.stack = [
+        "Foo@http://localhost:8080/assets/app/first.js:13:10",
+        "Bar@http://localhost:8080/assets/app/second.js:13:10",
+        "Baz@http://localhost:8080/assets/app/third.js:13:10"
+      ].join("\n")
+
+      span.setError(error)
+      span.cleanBacktracePath([
+        path => (path.indexOf("first") !== -1 ? "foo.js" : undefined),
+        path => (path.indexOf("second") !== -1 ? "bar.js" : undefined)
+      ])
+
+      const backtrace = span.serialize().error.backtrace
+      expect(backtrace).toEqual([
+        "[email protected]:13:10",
+        "[email protected]:13:10",
+        "Baz@http://localhost:8080/assets/app/third.js:13:10"
+      ])
+
+      expect(span.serialize().environment).toMatchObject({
+        backtrace_paths_matched: "2"
+      })
+    })
   })
 
   describe("getAction", () => {

packages/javascript/src/index.ts

@@ -14,17 +14,17 @@ import { toHashMap } from "./hashmap"
 import { VERSION } from "./version"
 import { PushApi } from "./api"
 import { Environment } from "./environment"
-import { Span } from "./span"
+import { Span, toBacktraceMatcher } from "./span"
 export { Span }
 import { Queue } from "./queue"
 import { Dispatcher } from "./dispatcher"
 
-import { AppsignalOptions } from "./options"
+import { AppsignalOptions, BacktraceMatcher } from "./options"
 
 export default class Appsignal {
   public VERSION = VERSION
   public ignored: RegExp[] = []
-  private matchBacktracePaths: RegExp[] = []
+  private backtraceMatchers: BacktraceMatcher[] = []
 
   private _dispatcher: Dispatcher
   private _options: AppsignalOptions
@@ -83,15 +83,21 @@ export default class Appsignal {
     }
 
     if (matchBacktracePaths) {
+      let paths: (RegExp | BacktraceMatcher)[]
+
       if (Array.isArray(matchBacktracePaths)) {
-        this.matchBacktracePaths = matchBacktracePaths
+        paths = matchBacktracePaths
       } else {
-        this.matchBacktracePaths = [matchBacktracePaths]
+        paths = [matchBacktracePaths]
       }
 
-      this.matchBacktracePaths = this.matchBacktracePaths
-        .filter(value => value instanceof RegExp)
-        .map(unglobalize)
+      for (const matcher of paths) {
+        if (matcher instanceof RegExp) {
+          this.backtraceMatchers.push(toBacktraceMatcher(unglobalize(matcher)))
+        } else if (typeof matcher === "function") {
+          this.backtraceMatchers.push(matcher)
+        }
+      }
     }
 
     this._dispatcher = new Dispatcher(this._queue, this._api)
@@ -242,7 +248,7 @@ export default class Appsignal {
       return
     }
 
-    span.cleanBacktracePath(this.matchBacktracePaths)
+    span.cleanBacktracePath(this.backtraceMatchers)
 
     if (Environment.supportsPromises()) {
       // clear breadcrumbs as they are now loaded into the span,