Bug: display json truncates output in show running-config (ConfD 8.0.6 only)

General
1

Hi all,

We’ve encountered a reproducible issue in ConfD 8.0.6, where the CLI command:

show running-config <path> | display json

produces truncated output — specifically, the beginning of the JSON is missing when the data is long.
e.g.:

CLI

show running-config service-port | display json | nomore

Expected output

{
  "data": {
    "my-module:service-port": [
      {
        "id": 1,
        ...

Actual output (in ConfD 8.0.6):

,
  {
    "id": 1,
    ...

The opening {, "data", and the module name key are missing entirely, making the JSON invalid.

Summury

  • It does not occur in XML output
  • It does not occur in NETCONF
  • It does not occur in ConfD 7.2.6

This appears to be a regression bug introduced in ConfD 8.0.6, likely within the CLI JSON output streaming logic.

Could someone confirm whether this issue is known and provide any guidance?

Thanks in advance!

2

Hi. I tried 8.0.10 with some existing data and did not see any issue. So, it is possible that my data isn’t showing it or that the issue was found and fixed. If you can provide a simple YANG and some sample data for it that shows the issue, I can try it and let you know.

Best,
Scott

3

Hi Scott,

Thanks for getting back to me.

Sure — I’ve attached a simplified YANG model that reproduces the issue, along with some example data for testing here.

To trigger the bug, please run the following command:

show running-config service-port interface 1/1/1 | display json | nomore

I realized I had omitted the interface 1/1/1 part in my original description — my apologies.

It also reproduces with interface 1/1/2 and some other similar entries.

Looking forward to your feedback.

Best regards,
Ittalo

4

Hi,

The data was helpful for a reproduction and then comparison to the behavior in later versions. The bug was fixed in ConfD 8.1 (and later) with the CHANGES entry:

  - cli: The '| display json' filter now correctly produces the whole output
    instead of sometimes cutting it short.

Based on the state of the 8.0 release at the time, the fix was not backported in 8.0.

Regards,
Scott

5

Hi Scott,

Thanks for the clarification — that was very helpful.

Would it be possible to get a patch for ConfD 8.0.6 to address this issue? Or is the recommended path to upgrade ConfD?

Thanks again!

6

Hi. The policy is to only fix and the head of the release so no patch to 8.0.6 would be possible. And, because the fix is only in the 8.1 and later releases and this would not qualify as a security issue, it will not be backported to 8.0, even to the head of that branch.

Regards,
Scott

7

Hi Scott,

Thank you again!

We’re discussing internally whether it’s worth upgrading ConfD at this point.

I really appreciate your help.

Regards,
Ittalo