Feature request: Include cause in stack trace

[everett1992]

Use case

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error/cause

The cause data property of an Error instance indicates the specific original cause of the error.

Error's cause property is a useful way to provide extra information about an error, particularly because it is a structured object, rather than adding to the string message.

However powertools does not include cause in log messages

import { Logger } from '@aws-lambda-powertools/logger'
const err = new Error('message', { cause : new Error('cause') })
console.log(err)
new Logger().error("err", err)

Error: message
    at file://test.mjs:2:13
    at ModuleJob.run (node:internal/modules/esm/module_job:193:25)
    ... 3 lines matching cause stack trace ...
    at async handleMainPromise (node:internal/modules/run_main:65:12) {
  [cause]: Error: cause
      at file://test.mjs:2:44
      at ModuleJob.run (node:internal/modules/esm/module_job:193:25)
      at async Promise.all (index 0)
      at async ESMLoader.import (node:internal/modules/esm/loader:530:24)
      at async loadESM (node:internal/process/esm_loader:91:5)

{
    "level": "ERROR",
    "message": "err",
    "service": "service_undefined",
    "timestamp": "2023-03-09T19:27:32.538Z",
    "error": {
        "name": "Error",
        "location": "node:internal/modules/esm/module_job:193",
        "message": "message",
        "stack": "Error: message\n    at file://test.mjs:2:13\n    at ModuleJob.run (node:internal/modules/esm/module_job:193:25)\n    at async Promise.all (index 0)\n    at async ESMLoader.import (node:internal/modules/esm/loader:530:24)\n    at async loadESM (node:internal/process/esm_loader:91:5)\n    at async handleMainPromise (node:internal/modules/run_main:65:12)"
    }
}

Solution/User Experience

powertools should include cause when it is defined.

Alternative solutions

No response

Acknowledgment

• This feature request meets Lambda Powertools Tenets
• Should this be considered in other Lambda Powertools languages? i.e. Python, Java, and .NET

Future readers

Please react with 👍 and your use case to help us understand customer demand.

[dreamorosi]

Hi @everett1992, thank you for opening this issue.

I agree with you that having the cause in the logs when there's an error would be beneficial and provide additional context to users.

I'm going to add this to the backlog and also mark it as help-wanted / good-first-issue to signal that the issue is open for contributions.

If anyone is interested in picking this up, please leave a comment below to agree on the scope with a maintainer and ask any question before starting to work on a PR.

[dVp007]

Hello @dreamorosi I would like to work on the PR.

[dreamorosi]

Hi @dVp007, thank you for offering to work on this issue.

Unfortunately after looking into it a bit more, I don't think we can support the feature just yet. The cause field was added in Node.js starting from version v16.9.0 (source), and at the moment we are committed to offer feature parity for versions 14.x through 18.x, which means we can't offer this feature for the time being.

I should have checked this better before marking the feature as status/confirmed, apologies for the confusion. I'm going to mark this as status/blocked and we'll revisit this once we decide to drop support for Node.js 14.x. We don't have an ETA to share at the moment but it'll likely happen sometime after Lambda will announce its deprecation or EOL.

---

If you're still interested in contributing, I'd encourage you to look for other issues marked as good-first-issue. Thank you for your understanding.

[everett1992]

I think this can be implemented while supporting node 14. `if (error.cause)` should not cause issues on any runtime

…

On Fri, Mar 10, 2023, 2:39 AM Andrea Amorosi ***@***.***> wrote: Hi @dVp007 <https://github.com/dVp007>, thank you for offering to work on this issue. Unfortunately after looking into it a bit more, I don't think we can support the feature just yet. The cause field was added in Node.js starting from version v16.9.0 (source <https://nodejs.org/api/errors.html#errorcause>), and at the moment we are committed to offer feature parity for versions 14.x through 18.x, which means we can't offer this feature for the time being. I should have checked this better before marking the feature as status/confirmed, apologies for the confusion. I'm going to mark this as status/blocked and we'll revisit this once we decide to drop support for Node.js 14.x. We don't have an ETA to share at the moment but it'll likely happen sometime after Lambda will announce its deprecation or EOL. ------------------------------ If you're still interested in contributing, I'd encourage you to look for other issues marked as good-first-issue. Thank you for your understanding. — Reply to this email directly, view it on GitHub <#1361 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAE6WM4VTGDYDUR7SYXLO5LW3MAHFANCNFSM6AAAAAAVVQ54KE> . You are receiving this because you were mentioned.Message ID: ***@***.*** com>

[mistaecko]

@dreamorosi Can you please elaborate on your reasoning not to support error cause. This language feature is a major improvement to error handling and logging, and the decision not to support it in Powertools is quite surprising.

If user code targets ES2022 and supporting node versions (>= 16.9.0), and logs errors with error cause property, I would really expect the logger to print the additional information (just as the native console.log would). This is not merely a convenience, but rather crucial for obtaining necessary information for troubleshooting.

Powertools is preventing us from using a modern language feature. Just as with other language features, there is no expectation for Powertools to polyfill this feature for older node versions.
That said, it should be easy enough for user code to install a shim, and any implementation in Powertools that inspects errror.cause should work just as well.

[niko-achilles]

i am also interested in this feature of supporting the cause property in logs . If that helps to prioritise.

[dreamorosi]

Hi both, thank you for taking the time to show interest in this feature - this definitely helps us with prioritization and to understand demand.

My initial push back towards adding the feature came from wanting to offer a cohesive Powertools experience across runtimes. Since the issue was opened however there seems to be a lot more demand that I anticipated so I'm more than open to reconsider.

On a general level I'm not keen on introducing a polyfill and after an initial proof of concept, the approach suggested by @everett1992 here, seems to be enough.

Given that the Node API doesn't seem to specify any strong type/value for cause, and given that in JavaScript you can throw other values other than Error I'm thinking on supporting the following three cases:

1. Logging an error with cause of Error type, formats both the error and the cause as errors:

logger.error(
  "something went wrong",
  new Error("boom", { cause: new Error("foo") })
);
// prints
{
    "level": "ERROR",
    "message": "something went wrong",
    "service": "service_undefined",
    "timestamp": "2023-07-14T11:53:06.944Z",
    "error": {
        "name": "Error",
        "location": "/Users/aamorosi/Codes/error-cause/index.ts:8",
        "message": "boom",
        "stack": "Error: boom\n    at Object.<anonymous> (/Users/aamorosi/Codes/error-cause/index.ts:8:3)\n    at Module._compile (node:internal/modules/cjs/loader:1159:14)\n    at Module._extensions..js (node:internal/modules/cjs/loader:1213:10)\n    at Module.load (node:internal/modules/cjs/loader:1037:32)\n    at Module._load (node:internal/modules/cjs/loader:878:12)\n    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)\n    at node:internal/main/run_main_module:23:47",
        "cause": {
            "name": "Error",
            "location": "/Users/aamorosi/Codes/error-cause/index.ts:8",
            "message": "foo",
            "stack": "Error: foo\n    at Object.<anonymous> (/Users/aamorosi/Codes/error-cause/index.ts:8:30)\n    at Module._compile (node:internal/modules/cjs/loader:1159:14)\n    at Module._extensions..js (node:internal/modules/cjs/loader:1213:10)\n    at Module.load (node:internal/modules/cjs/loader:1037:32)\n    at Module._load (node:internal/modules/cjs/loader:878:12)\n    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)\n    at node:internal/main/run_main_module:23:47"
        }
    }
}

2 Logging an error with cause of types other than Error (i.e. string) formats the error and appends the cause as-is.

logger.error("something went wrong", new Error("boom", { cause: "something" }));
// prints
{
    "level": "ERROR",
    "message": "something went wrong",
    "service": "service_undefined",
    "timestamp": "2023-07-14T11:53:06.959Z",
    "error": {
        "name": "Error",
        "location": "/Users/aamorosi/Codes/error-cause/index.ts:13",
        "message": "boom",
        "stack": "Error: boom\n    at Object.<anonymous> (/Users/aamorosi/Codes/error-cause/index.ts:13:38)\n    at Module._compile (node:internal/modules/cjs/loader:1159:14)\n    at Module._extensions..js (node:internal/modules/cjs/loader:1213:10)\n    at Module.load (node:internal/modules/cjs/loader:1037:32)\n    at Module._load (node:internal/modules/cjs/loader:878:12)\n    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)\n    at node:internal/main/run_main_module:23:47",
        "cause": "something"
    }
}

3. When the error is not present, the error is formatted without any cause key. This is the current behavior and is in line with Logger's behavior of removing undefined values from the logs.

logger.error("something went wrong", new Error("boom"));
// prints
{
    "level": "ERROR",
    "message": "something went wrong",
    "service": "service_undefined",
    "timestamp": "2023-07-14T11:53:06.958Z",
    "error": {
        "name": "Error",
        "location": "/Users/aamorosi/Codes/error-cause/index.ts:11",
        "message": "boom",
        "stack": "Error: boom\n    at Object.<anonymous> (/Users/aamorosi/Codes/error-cause/index.ts:11:38)\n    at Module._compile (node:internal/modules/cjs/loader:1159:14)\n    at Module._extensions..js (node:internal/modules/cjs/loader:1213:10)\n    at Module.load (node:internal/modules/cjs/loader:1037:32)\n    at Module._load (node:internal/modules/cjs/loader:878:12)\n    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)\n    at node:internal/main/run_main_module:23:47"
    }
}

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