docs(identity): clarify extension points and add custom identity prov…

[sid200727]

Summary:
This PR improves the Identity Service documentation to make it easier for new contributors and users to understand how it works and how it can be extended.

What’s included:
• A brief explanation of how the Identity Service is used within the SDK
• Clear guidance on common extension points (identity providers, key managers, roles)
• A simple Go example showing how a custom identity provider could be implemented

Why this change:
The existing documentation explains the architecture well but does not clearly show how developers can extend the Identity Service.
These additions aim to reduce confusion and lower the learning curve.

Related issue:
#1008

[sid200727]

It looks like the failures are coming from cache restore errors (/usr/bin/tar exit code 2) across multiple matrix jobs.

Since this PR only updates documentation, I suspect this may be a CI/cache issue rather than a change-related failure.

Please let me know if you’d like me to rebase or try anything specific.

[adecaro]

Hi @sid200727 , thanks for submitting this PR.
First two comments:

• Please, fix the DCO by following the instructions here: https://github.com/hyperledger-labs/fabric-token-sdk/pull/1326/checks?check_run_id=63352288280
• Please, link identity.md from docs/services.md. There is already a bullet for the identity service but was not linked.

Thanks much, I will now look at additions.

[adecaro]

Please, move this section at the end of document because it contains content for pro developers.

[adecaro]

indeed, via key managers

[adecaro]

I would rather focus on two interfaces required by the local membership: KeyManagerProvider and KeyManager both under identity/membership. The default implementations are X509 based and idemix as described in the Default Key Managers section.

[adecaro]

this can be done via introducing a key manager or composing existing identity types, examples are in the Other Identity Types section

[adecaro]

Thanks a lot for the effort. Left comments to help moving forward.

[sid200727]

Hi,
Thank you for the detailed feedback.

I’ve made the requested changes:
• Moved the “Extending the Identity Service” section to the end of the document
• Updated the extension scenarios to clearly reference KeyManager and KeyManagerProvider
• Refocused the example on KeyManager/KeyManagerProvider under identity/membership
• Linked identity.md from docs/services.md
• Fixed DCO sign-off

Please let me know if any further refinements are needed.

[adecaro]

I think we can remove this section because it does not match the current code.

[adecaro]

HI @sid200727 , just this one is left and then we are good. Thanks 👍

[sid200727]

Hi @adecaro,

Thanks for the clarification.

I’ve removed the “Custom KeyManager Implementation” example section that did not match the current codebase.

Please let me know if any further refinements are needed.

[adecaro]

Hi @sid200727 , did you push your last changes?
There are also changes to config.go. These look like as belonging to a different PR.

[sid200727]

Hi @adecaro,

Thanks for spotting this.
You're right the changes to config.go belong to a different PR and were accidentally pushed to this branch.
I will remove those commits from this PR and keep it focused strictly on documentation.

Thanks for the patience.

[adecaro]

@sid200727 , please, don't forget to always use -s when generating commits. Please, address the DCO requirement following the instructions here: https://github.com/hyperledger-labs/fabric-token-sdk/pull/1326/checks?check_run_id=63714459289

There is only one section that needs to be removed and then we are done.

Thanks very much for this effort.

[sid200727]

Hi @adecaro,

Thanks again for the guidance.
I’ve rebuilt the branch cleanly on top of main, and this PR now contains only the intended documentation changes in docs/services/identity.md.
All unrelated changes have been removed, and the history has been simplified into a single signed-off commit.

Please let me know if anything else should be refined.

[adecaro]

Hi @sid200727 , it is strange, when I check the files here: https://github.com/hyperledger-labs/fabric-token-sdk/pull/1326/changes I still see the paragraph we agreed to remove. What can it be?

[sid200727]

Hi @adecaro,

Thanks, I’ve now removed the remaining “Custom KeyManager Implementation” example section.

This PR should now reflect only the intended documentation changes.

Please let me know if anything else needs refinement.

[sid200727]

@adecaro

After updating the branch with latest main, the coverage check shows a -0.009% decrease (25.6%).

This PR only contains documentation changes, so no code or test logic was modified.

Please let me know if you would like me to take any action here, or if this can be overridden.

Thanks again.

[adecaro]

LGTM