Initial commit: CarrotAssistant backend (Go + Gin + SQLite, OpenAI-compatible agent runtime)

internal/store/db.go

@@ -0,0 +1,45 @@
+package store
+
+import (
+	"fmt"
+
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
+)
+
+// Open opens (or creates) the SQLite database at path and runs GORM
+// AutoMigrate for all models. SQLite with WAL is used for single-instance
+// durability; the abstraction lives entirely in this package so a future
+// migration to Postgres stays localised.
+func Open(path string) (*gorm.DB, error) {
+	// _busy_timeout helps under concurrent writes; _foreign_keys enforces FK
+	// constraints that GORM expects; _journal_mode=WAL improves read/write
+	// concurrency for the single-file database.
+	dsn := fmt.Sprintf("%s?_busy_timeout=5000&_foreign_keys=on&_journal_mode=WAL", path)
+	db, err := gorm.Open(sqlite.Open(dsn), &gorm.Config{
+		// Silent: our handlers emit their own HTTP errors and frequently run
+		// "first-or-create" / 404 lookups whose ErrRecordNotFound would
+		// otherwise spam the operator's logs.
+		Logger: logger.Default.LogMode(logger.Silent),
+	})
+	if err != nil {
+		return nil, fmt.Errorf("open sqlite: %w", err)
+	}
+
+	if err := db.AutoMigrate(
+		&AdminUser{},
+		&App{},
+		&ModelConfig{},
+		&Skill{},
+		&Session{},
+		&Message{},
+		&AuditLog{},
+	); err != nil {
+		return nil, fmt.Errorf("auto-migrate: %w", err)
+	}
+
+	// Compound uniqueness: a skill slug is unique per app. Enforced in code
+	// to avoid depending on DB-specific index syntax during migration.
+	return db, nil
+}

internal/store/models.go

@@ -0,0 +1,110 @@
+// Package store defines the persistence layer for CarrotAssistant.
+//
+// All persistent structured state lives here: admin accounts, applications,
+// model configurations, skill metadata, chat sessions and messages, and
+// audit logs. Skill *content* itself (the markdown file) lives on disk and
+// is managed by the skill package; this package only stores the metadata
+// needed to locate and govern that file (status, version, ownership).
+package store
+
+import (
+	"time"
+
+	"gorm.io/datatypes"
+)
+
+// AdminUser is an operator who can log in to the admin console.
+type AdminUser struct {
+	ID           int64     `gorm:"primaryKey;autoIncrement" json:"id"`
+	Username     string    `gorm:"uniqueIndex;size:64;not null" json:"username"`
+	PasswordHash string    `gorm:"size:255;not null" json:"-"`
+	CreatedAt    time.Time `json:"created_at"`
+	UpdatedAt    time.Time `json:"updated_at"`
+}
+
+// App is a target application (a forum, a resource site, ...). Each App owns
+// a set of Skills and exposes a Chat API guarded by its access token.
+type App struct {
+	ID            int64     `gorm:"primaryKey;autoIncrement" json:"id"`
+	Slug          string    `gorm:"uniqueIndex;size:64;not null" json:"slug"`
+	Name          string    `gorm:"size:128;not null" json:"name"`
+	Description   string    `gorm:"size:512" json:"description"`
+	TokenHash     string    `gorm:"size:255;not null" json:"-"` // SHA-256 hash of the access token; never store plaintext
+	ModelConfigID *int64    `gorm:"index" json:"model_config_id,omitempty"`
+	Status        string    `gorm:"size:32;not null;default:'active'" json:"status"` // active | disabled
+	CreatedAt     time.Time `json:"created_at"`
+	UpdatedAt     time.Time `json:"updated_at"`
+}
+
+// ModelConfig describes an OpenAI-compatible LLM endpoint. Any provider
+// speaking the OpenAI Chat Completions + tool-calling protocol (OpenAI,
+// DeepSeek, Moonshot, vLLM, Ollama, ...) can be wired in here.
+type ModelConfig struct {
+	ID              int64     `gorm:"primaryKey;autoIncrement" json:"id"`
+	Name            string    `gorm:"uniqueIndex;size:64;not null" json:"name"`
+	BaseURL         string    `gorm:"size:255;not null" json:"base_url"`
+	APIKeyEncrypted string    `gorm:"size:512;not null" json:"-"` // AES-GCM ciphertext, base64
+	APIKeyPreview   string    `gorm:"size:16" json:"api_key_preview"` // last 4 chars, display only
+	DefaultModel    string    `gorm:"size:64;not null" json:"default_model"`
+	SupportsTools   bool      `gorm:"not null;default:true" json:"supports_tools"`
+	MaxTokens       int       `gorm:"default:0" json:"max_tokens"` // 0 = leave unset
+	CreatedAt       time.Time `json:"created_at"`
+	UpdatedAt       time.Time `json:"updated_at"`
+}
+
+// Skill is the metadata row for a skill markdown file. The markdown content
+// (system prompt + tool definitions) lives at FilePath; this row only governs
+// lifecycle (draft/published/archived), versioning, and ownership.
+type Skill struct {
+	ID          int64     `gorm:"primaryKey;autoIncrement" json:"id"`
+	AppID       int64     `gorm:"index;not null" json:"app_id"`
+	Slug        string    `gorm:"size:64;not null" json:"slug"` // unique within app
+	Name        string    `gorm:"size:128;not null" json:"name"`
+	Description string    `gorm:"size:512" json:"description"`
+	FilePath    string    `gorm:"size:512;not null" json:"file_path"` // path under SkillsDir
+	Version     int       `gorm:"not null;default:1" json:"version"`
+	Status      string    `gorm:"size:32;not null;default:'draft'" json:"status"` // draft | published | archived
+	Source      string    `gorm:"size:32" json:"source"`                            // openapi | markdown | source | manual
+	PublishedAt *time.Time `json:"published_at,omitempty"`
+	CreatedAt   time.Time `json:"created_at"`
+	UpdatedAt   time.Time `json:"updated_at"`
+}
+
+// Session is a chat conversation between an end-user and an App's assistant.
+type Session struct {
+	ID           string         `gorm:"primaryKey;type:text" json:"id"` // UUID
+	AppID        int64          `gorm:"index;not null" json:"app_id"`
+	Title        string         `gorm:"size:255" json:"title"`
+	MessageCount int            `gorm:"not null;default:0" json:"message_count"`
+	// PendingConfirmation, when non-empty, holds a JSON blob describing a
+	// mutating tool call awaiting the user's approval. The chat stream pauses
+	// until POST /chat/confirm resolves it. Empty = no pending call.
+	PendingConfirmation datatypes.JSON `json:"pending_confirmation,omitempty"`
+	CreatedAt            time.Time      `json:"created_at"`
+	UpdatedAt            time.Time      `json:"updated_at"`
+}
+
+// Message is a single message within a Session. Role follows the OpenAI
+// convention: system | user | assistant | tool. ToolCalls stores the
+// assistant's tool call payload (JSON) when present.
+type Message struct {
+	ID         int64         `gorm:"primaryKey;autoIncrement" json:"id"`
+	SessionID  string        `gorm:"index;not null" json:"session_id"`
+	Role       string        `gorm:"size:32;not null" json:"role"` // system | user | assistant | tool
+	Content    string        `gorm:"type:text" json:"content"`
+	ToolCalls  datatypes.JSON `json:"tool_calls,omitempty"`
+	ToolCallID string        `gorm:"size:64" json:"tool_call_id,omitempty"` // for role=tool, the call id it answers
+	Tokens     int           `gorm:"default:0" json:"tokens"`
+	CreatedAt  time.Time     `json:"created_at"`
+}
+
+// AuditLog records security-relevant actions for traceability.
+type AuditLog struct {
+	ID        int64          `gorm:"primaryKey;autoIncrement" json:"id"`
+	AppID     *int64         `gorm:"index" json:"app_id,omitempty"`
+	SessionID *string        `gorm:"index" json:"session_id,omitempty"`
+	Actor     string         `gorm:"size:128" json:"actor"` // admin username, "system", app slug, ...
+	Action    string         `gorm:"size:64;not null;index" json:"action"`
+	Detail    datatypes.JSON `json:"detail"`
+	CreatedAt time.Time      `gorm:"index" json:"created_at"`
+}