Docs · Tower

Architecture

Tower is built as a Backstage frontend module consisting of tab-based UI, data-fetching hooks, and utility components for cloud-native platform visibility.

Module Structure

plugin/src/tower/
├── index.tsx                    # Route entry point
├── useReleaseContext.ts         # Release data context
├── useFleetEnvironments.tsx      # Environment state management
├── useConfigData.ts             # Config schema and validation
│
├── [Tabs] — Primary Views
│   ├── Overview/                # Fleet status, recent activity, metrics
│   ├── Releases/                # Release records, promotion workflows
│   ├── PRs/                      # Pull request CI/CD status
│   ├── Pipelines/               # Tekton pipeline execution
│   └── Config/                  # Cluster config inspection
│
├── [Components] — Shared UI
│   ├── PipelineFlow.tsx         # DAG-based pipeline visualization
│   ├── ReleaseRecordDetail.tsx  # Release record view with promotion
│   ├── ArgoCD*.tsx              # ArgoCD integration components
│   ├── EnvPicker.tsx            # Environment selector
│   └── ...
│
├── [Utilities]
│   ├── schemaValidate.ts        # YAML schema validation
│   ├── YamlBlockEditor.tsx      # YAML editing UI
│   ├── PodLogsView.tsx          # Pod log streaming
│   └── nicknameCache.ts         # Cache for Tekton task names
└── [Hooks]
    ├── useSlos.ts              # SLO tracking
    ├── useReleaseRecordPersistence.ts  # Release persistence
    └── useConfigData.ts        # Config queries

Data Flow

Release Records

Backstage Context
  ↓
useReleaseContext.ts (fetch from API)
  ↓
Releases tab / ReleaseRecordDetail component
  ↓
PromoteDialog (environment promotion)
  ↓
useReleaseRecordPersistence (commit to git)

Cluster State

Kubernetes API
  ↓
useFleetEnvironments.tsx (cache environments, watch events)
  ↓
Overview / Config tabs
  ↓
Live status, SLO metrics, activity feeds

CI/CD Pipelines

Tekton API
  ↓
PipelineRunList (list runs)
  ↓
PipelineFlow (render DAG)
  ↓
TaskRunLogConsole (stream logs)

Key Design Decisions

No Backend Services

Tower reads directly from:

• Kubernetes API (via kubeconfig or in-cluster credentials)
• ArgoCD API (direct HTTP calls)
• Tekton Dashboard or Tekton API

This eliminates the operational burden of a dedicated backend service — all queries go through standard APIs.

Release Records as Git State

Release records (promotions, approvals, metadata) are persisted as git commits, not in a database. This ensures:

• Auditability (full git history)
• No additional persistence layer
• GitOps alignment with infrastructure management

Context + Hooks over Redux

State management uses React Context (for release data) and custom hooks (for cluster state), not Redux. Justification:

• Simpler onboarding
• Avoids action/reducer boilerplate
• Still supports derived state and memoization

Integration Points

ArgoCD

• Fetch Application status, sync state, last sync time
• Trigger manual sync, force sync
• Application-to-namespace mapping for environment visibility

Tekton

• List TaskRuns and PipelineRuns
• Stream pod logs for live task debugging
• Render pipeline DAG from Run status

External Secrets Operator

• Show secret sync status, last fetch time
• Detect stale credentials

Crossplane

• Show composed resources per application
• Track readiness, synced condition
• Alert on composition errors

Performance Considerations

Caching Strategy

• Environments cached with 30-second TTL
• Release records cached during session
• Watch connections for live updates where available

Pagination

• Release records paginated (default 20 per page)
• Pipeline runs use cursor pagination

Lazy Loading

• Tabs load data on-demand, not all at once
• Pod logs loaded on-request
• Config inspection deferred until user navigates to tab