Rewrite/reconcile manager

[Tanker2020]

PR-5 — Reconcile Manager

Base branch: rewrite/Resource_Verification (must be merged first — see merge order below)

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Summary

This PR ports the core reconciliation engine from Python oper8 to Go, wiring all four previously-merged packages (dag, deploymanager, status, verify) into a working end-to-end reconcile loop.

Files added:

Package	File	What it is
session/	session.go	Per-reconcile context struct — owns CR manifest, DeployManager, component Graph, and current cluster status
component/	component.go	Component interface: Name(), Setup(), Deploy(), Verify()
controller/	controller.go	Controller interface + BaseController embed with no-op defaults for all optional hooks
rolloutmanager/	rolloutmanager.go	4-phase rollout loop: Deploy graph → AfterDeploy hook → Verify graph → AfterVerify hook
reconcilemanager/	reconcilemanager.go	Top-level orchestrator: generates reconcile ID, constructs session, checks preconditions, drives rollout, writes status, manages finalizers

Files modified:

File	Change
dag/node.go	Added Node.SetFunc(), Node.SetData(), Node.Data() — needed by RolloutManager to wire component functions onto graph nodes
dag/runner.go	Removed unused last / inFlight fields (fixes lint failure from previous push); gofmt
deploymanager/dryrun.go	gofmt only

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Design decisions vs Python

Python	Go
Session owned by ReconcileManager, passed everywhere	Session is a plain struct created once per Reconcile() call
Component ABC with auto-registration in __init__	Minimal 3-method interface; operators call sess.AddComponent() explicitly in SetupComponents
Controller abstract class properties (group, version, kind)	GVK() method returns a plain struct
@precondition decorator	[]PreconditionFunc slice on Options
ThreadPoolExecutor + sleep-poll	dag.Runner goroutines with context.Context cancellation
RolloutManager stored 4 separate callback vars	Receives controller.Controller directly; calls hook methods on it
ReconcileManager reimported controllers dynamically	Receives a fully-constructed controller.Controller — no reflection

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Rollout phases

Phase 1 — Deploy graph runner.Run(ctx) → Setup + Deploy each component in DAG order
Phase 2 — AfterDeploy ctrl.AfterDeploy / ctrl.AfterDeployUnsuccessful hook
Phase 3 — Verify graph runner.Run(ctx) → Verify each deployed component
Phase 4 — AfterVerify ctrl.AfterVerify / ctrl.AfterVerifyUnsuccessful hook

Context cancellation propagates into both Runner executions. A fatal error in Phase 1 skips Phase 3 entirely. Phase 2 returning not-OK prevents VerifyCompleted() from being true even if all nodes verified.

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Tests

Package	Cases	Coverage highlights
session	21	Construction, all CR field accessors, current version from status, empty-status handling, all 5 CR validation errors, AddComponent / AddDependency (ok + error), ScopedName, TruncateName (passthrough, exact boundary, over boundary, uniqueness)
controller	14	GVK fields, HookResult, all BaseController defaults (no-op / OK / false), override behaviour for ShouldRequeue, HasFinalizer, Finalizer
rolloutmanager	18	Empty graph, single component happy path, ordered pair, setup/deploy errors (fatal), deploy error blocks downstream, verify-not-ready (non-fatal + blocks downstream), after-deploy called/not-called/error, after-verify called/not-called/error, 3-component all-verified, independent branch runs despite upstream failure, concurrent execution
reconcilemanager	24	Empty graph, single verified, setup error, deploy error, verify-not-ready, ShouldRequeue true/false, precondition fail/multi-stop/all-pass, finalizer calls finalize-not-setup / error / stamps object, invalid CR (missing kind/apiVersion/metadata), two-component ordering, failed-blocks-dependent, status stable / error / verify-wait, ManageStatus=false writes nothing, ReconcileResult defaults

Total new tests: 77 across 4 packages. All run with -race.

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Merge order

PRs must be merged in sequence:

PR-1 (DAG Runner) → PR-2 (Deploy Manager) → PR-3 (Status Management) → PR-4 (Resource Verification) → PR-5 (this PR)

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What this PR does NOT include

• controller-runtime adapter (Reconcile(ctx, req) (ctrl.Result, error)) — that is a thin wrapper and can be added as a follow-up or in PR-6
• watch_manager port — tracked as PR-6
• A working main.go / operator binary — see the smoke-test plan in the thread context for how to wire one up once this lands