git.stella-ops.org/docs/dev/32_AUTH_CLIENT_GUIDE.md

StellaOps Auth Client — Integration Guide

Status: Drafted 2025-10-10 as part of LIB5. Consumer teams (Feedser, CLI, Agent) should review before wiring the new options into their configuration surfaces.

The StellaOps.Auth.Client library provides a resilient OpenID Connect client for services and tools that talk to StellaOps Authority. LIB5 introduced configurable HTTP retry/backoff policies and an offline-fallback window so downstream components stay deterministic even when Authority is briefly unavailable.

This guide explains how to consume the new settings, when to toggle them, and how to test your integration.

1. Registering the client

services.AddStellaOpsAuthClient(options =>
{
    options.Authority = configuration["StellaOps:Authority:Url"]!;
    options.ClientId = configuration["StellaOps:Authority:ClientId"]!;
    options.ClientSecret = configuration["StellaOps:Authority:ClientSecret"];
    options.DefaultScopes.Add("feedser.jobs.trigger");

    options.EnableRetries = true;
    options.RetryDelays.Clear();
    options.RetryDelays.Add(TimeSpan.FromMilliseconds(500));
    options.RetryDelays.Add(TimeSpan.FromSeconds(2));

    options.AllowOfflineCacheFallback = true;
    options.OfflineCacheTolerance = TimeSpan.FromMinutes(5);
});

Reminder: AddStellaOpsAuthClient binds the options via IOptionsMonitor<T> so changes picked up from configuration reloads will be applied to future HTTP calls without restarting the host.

2. Resilience options

Option	Default	Notes
EnableRetries	true	When disabled, the shared Polly policy is a no-op and HTTP calls will fail fast.
RetryDelays	1s, 2s, 5s	Edit in ascending order; zero/negative entries are ignored. Clearing the list and leaving it empty keeps the defaults.
AllowOfflineCacheFallback	true	When true, stale discovery/JWKS responses are reused within the tolerance window if Authority is unreachable.
OfflineCacheTolerance	00:10:00	Added to the normal cache lifetime. E.g. a 10 minute JWKS cache plus 5 minute tolerance keeps keys for 15 minutes if Authority is offline.

The HTTP retry policy handles:

• 5xx responses
• 429 responses
• Transient transport failures (HttpRequestException, timeouts, aborted sockets)

Retries emit warnings via the StellaOps.Auth.Client.HttpRetry logger. Tune the delay values to honour your deployment’s SLOs.

3. Configuration mapping

Suggested configuration keys (coordinate with consuming teams before finalising):

StellaOps:
  Authority:
    Url: "https://authority.stella-ops.local"
    ClientId: "feedser"
    ClientSecret: "change-me"
    AuthClient:
      EnableRetries: true
      RetryDelays:
        - "00:00:01"
        - "00:00:02"
        - "00:00:05"
      AllowOfflineCacheFallback: true
      OfflineCacheTolerance: "00:10:00"

Environment variable binding follows the usual double-underscore rules, e.g.

STELLAOPS__AUTHORITY__AUTHCLIENT__RETRYDELAYS__0=00:00:02
STELLAOPS__AUTHORITY__AUTHCLIENT__OFFLINECACHETOLERANCE=00:05:00

CLI and Feedser teams should expose these knobs once they adopt the auth client.

4. Testing recommendations

1. Unit tests: assert option binding by configuring StellaOpsAuthClientOptions via a ConfigurationBuilder and ensuring Validate() normalises the retry delays and scope list.
2. Offline fallback: simulate an unreachable Authority by swapping HttpMessageHandler to throw HttpRequestException after priming the discovery/JWKS caches. Verify that tokens are still issued until the tolerance expires.
3. Observability: watch for StellaOps.Auth.Client.HttpRetry warnings in your logs. Excessive retries mean the upstream Authority cluster needs attention.
4. Determinism: keep retry delays deterministic. Avoid random jitter—operators can introduce jitter at the infrastructure layer if desired.

5. Rollout checklist

• Update consuming service/CLI configuration schema to include the new settings.
• Document recommended defaults for offline (air-gapped) versus connected deployments.
• Extend smoke tests to cover Authority outage scenarios.
• Coordinate with Docs Guild so user-facing quickstarts reference the new knobs.

Once Feedser and CLI integrate these changes, we can mark LIB5 DONE; further packaging work is deferred until the backlog reintroduces it.