godoxy-yusing/internal/route/README.md

# Route

Provides HTTP routing, reverse proxy, file serving, and TCP/UDP stream proxying for GoDoxy.

## Overview

The `internal/route` package implements the core routing system for GoDoxy. It handles reverse proxying HTTP requests, serving static files, and proxying TCP/UDP streams. Routes can be discovered from Docker containers, YAML files, or remote agents.

### Primary Consumers

- **Route providers**: Create and manage route instances
- **HTTP server**: Dispatches requests to route handlers
- **Configuration layer**: Validates and loads route configs

### Non-goals

- Does not implement container runtime operations (delegates to providers)
- Does not handle authentication (delegates to middleware/rules)
- Does not manage health checks (delegates to `internal/health/monitor`)

### Stability

Internal package with stable core types. Route configuration schema is versioned.

## Public API

### Exported Types

```go
type Route struct {
    Alias  string       // Unique route identifier
    Scheme Scheme       // http, https, h2c, tcp, udp, fileserver
    Host   string       // Virtual host
    Port   Port         // Listen and target ports

    // File serving
    Root  string        // Document root
    SPA   bool          // Single-page app mode
    Index string        // Index file

    // Route rules and middleware
    HTTPConfig
    PathPatterns []string
    Rules        rules.Rules
    RuleFile     string

    // Health and load balancing
    HealthCheck types.HealthCheckConfig
    LoadBalance *types.LoadBalancerConfig

    // Additional features
    Middlewares map[string]types.LabelMap
    Homepage    *homepage.ItemConfig
    AccessLog   *accesslog.RequestLoggerConfig
    Agent       string
    Idlewatcher *types.IdlewatcherConfig

    Metadata
}
```

```go
type Scheme string

const (
    SchemeHTTP      Scheme = "http"
    SchemeHTTPS     Scheme = "https"
    SchemeH2C       Scheme = "h2c"
    SchemeTCP       Scheme = "tcp"
    SchemeUDP       Scheme = "udp"
    SchemeFileServer Scheme = "fileserver"
)
```

```go
type ExcludedReason int

const (
    ExcludedReasonNone ExcludedReason = iota
    ExcludedReasonError
    ExcludedReasonManual
    ExcludedReasonNoPortContainer
    ExcludedReasonNoPortSpecified
    ExcludedReasonBlacklisted
    ExcludedReasonBuildx
    ExcludedReasonOld
)
```

### Exported Functions/Methods

```go
// Validation and lifecycle
func (r *Route) Validate() gperr.Error
func (r *Route) Start(parent task.Parent) gperr.Error
func (r *Route) Finish(reason any)
func (r *Route) Started() <-chan struct{}

// Route queries
func (r *Route) Impl() types.Route
func (r *Route) Task() *task.Task
func (r *Route) ProviderName() string
func (r *Route) TargetURL() *nettypes.URL
func (r *Route) References() []string

// Status queries
func (r *Route) ShouldExclude() bool
func (r *Route) UseLoadBalance() bool
func (r *Route) UseIdleWatcher() bool
func (r *Route) UseHealthCheck() bool
```

## Architecture

### Core Components

```mermaid
classDiagram
    class Route {
        +Validate() gperr.Error
        +Start(parent) gperr.Error
        +Finish(reason)
        +Started() &lt;-chan struct#123;#125;
    }

    class Metadata {
        +impl types.Route
        +task *task.Task
        +started chan struct#123;#125;
    }

    class HealthMonitor {
        +Start(parent) error
        +Healthy() bool
        +URL() string
    }

    Route --> Metadata : contains
    Route --> HealthMonitor : optional
```

### Route Types

```mermaid
graph TD
    Route --> HTTPRoute
    Route --> StreamRoute

    HTTPRoute --> ReverseProxyRoute
    HTTPRoute --> FileServer

    StreamRoute --> TCPStream
    StreamRoute --> UDPStream
```

### Request Processing Pipeline

```mermaid
flowchart LR
    A[Request] --> B[Route Matching]
    B --> C{Route Type}
    C -->|HTTP| D[Middleware]
    C -->|FileServer| E[File System]
    C -->|Stream| F[TCP/UDP Proxy]

    D --> G[Rules Engine]
    G --> H[Upstream]
    H --> I[Response]
    E --> I
    F --> I
```

### Reverse Proxy Flow

```mermaid
sequenceDiagram
    participant C as Client
    participant P as Proxy
    participant L as Load Balancer
    participant B as Backend

    C->>P: GET /
    P->>L: Select Backend
    L-->>P: Backend1
    P->>B: Forward Request
    B-->>P: 200 OK
    P-->>C: Response
```

## Configuration Surface

### Route Configuration

```go
type Route struct {
    Alias  string       `json:"alias"`
    Scheme Scheme       `json:"scheme"`
    Host   string       `json:"host,omitempty"`
    Port   Port         `json:"port"`
    Root   string       `json:"root,omitempty"`
    SPA    bool         `json:"spa,omitempty"`
    Index  string       `json:"index,omitempty"`
    // ... additional fields
}
```

### Docker Labels

```yaml
labels:
  proxy.aliases: myapp
  proxy.myapp.port: 3000
```

### YAML Configuration

```yaml
routes:
  myapp:
    scheme: http
    root: /var/www/myapp
    spa: true
```

## Dependency and Integration Map

| Dependency                       | Purpose                          |
| -------------------------------- | -------------------------------- |
| `internal/route/routes`          | Route registry and lookup        |
| `internal/route/rules`           | Request/response rule processing |
| `internal/route/stream`          | TCP/UDP stream proxying          |
| `internal/route/provider`        | Route discovery and loading      |
| `internal/health/monitor`        | Health checking                  |
| `internal/idlewatcher`           | Idle container management        |
| `internal/logging/accesslog`     | Request logging                  |
| `internal/homepage`              | Dashboard integration            |
| `github.com/yusing/goutils/errs` | Error handling                   |

## Observability

### Logs

- **INFO**: Route start/stop, validation results
- **DEBUG**: Request processing details
- **ERROR**: Proxy failures, health check failures

Log context includes: `alias`, `host`, `method`, `path`, `status`

### Metrics

Health check metrics via `internal/health/monitor`:

- `health_check_total`
- `health_check_failure_total`
- `health_check_duration_seconds`

## Security Considerations

- Route matching validates host and path patterns
- Upstream URL validation prevents SSRF attacks
- Rules engine can enforce authentication/authorization
- ACL integration available for IP-based access control

## Failure Modes and Recovery

| Failure                   | Behavior                   | Recovery                    |
| ------------------------- | -------------------------- | --------------------------- |
| Backend unavailable       | Returns 502 error          | Fix backend service         |
| Health check fails        | Route marked unhealthy     | Fix backend health endpoint |
| Route validation fails    | Route excluded with reason | Fix configuration           |
| TLS handshake fails       | Connection error           | Fix certificates            |
| Load balancer no backends | Returns 503 error          | Add healthy backends        |

## Usage Examples

### Creating a Basic HTTP Route

```go
route := &route.Route{
    Alias:  "myapp",
    Scheme: route.SchemeHTTP,
    Host:   "myapp.local",
    Port:   route.Port{Proxy: 8080, Target: 3000},
}

if err := route.Validate(); err != nil {
    return err
}

if err := route.Start(parent); err != nil {
    return err
}
```

### Route with Health Check

```go
route := &route.Route{
    Alias: "myservice",
    HealthCheck: types.HealthCheckConfig{
        Path:     "/health",
        Interval: 30 * time.Second,
        Timeout:  5 * time.Second,
    },
}
```

### File Server Route

```go
route := &route.Route{
    Alias:  "files",
    Scheme: route.SchemeFileServer,
    Root:   "/var/www/files",
    SPA:    false,
    Index:  "index.html",
}
```

## Testing Notes

- Unit tests for validation logic
- Integration tests with real backends
- Mock health monitors for testing
- Route exclusion tests cover all reason codes