feat: allow to load modules dynamically

internal/policy/engine.go

@@ -14,15 +14,28 @@ import (
 	"github.com/reposaur/reposaur/pkg/output"
 )
 
-type Option func(*Engine)
+type EngineOption func(*Engine)
 
 type Engine struct {
 	modules       map[string]*ast.Module
 	compiler      *ast.Compiler
 	enableTracing bool
 }
 
-func Load(ctx context.Context, policyPaths []string, opts ...Option) (*Engine, error) {
+func NewEngine(opts ...EngineOption) *Engine {
+	engine := &Engine{
+		modules:  map[string]*ast.Module{},
+		compiler: ast.NewCompiler().WithEnablePrintStatements(true),
+	}
+
+	for _, opt := range opts {
+		opt(engine)
+	}
+
+	return engine
+}
+
+func NewEngineWithPolicies(ctx context.Context, policyPaths []string, opts ...EngineOption) (*Engine, error) {
 	policies, err := loader.NewFileLoader().
 		WithProcessAnnotation(true).
 		Filtered(policyPaths, isRegoFile)
@@ -57,7 +70,7 @@ func Load(ctx context.Context, policyPaths []string, opts ...Option) (*Engine, e
 
 // WithTracingEnabled enables or disables policy
 // execution tracing.
-func WithTracingEnabled(enabled bool) Option {
+func WithTracingEnabled(enabled bool) EngineOption {
 	return func(e *Engine) {
 		e.enableTracing = enabled
 	}
@@ -90,6 +103,27 @@ func (e *Engine) Modules() map[string]*ast.Module {
 	return e.modules
 }
 
+func (e *Engine) LoadPolicy(filename, policy string) error {
+	module, err := ast.ParseModuleWithOpts(filename, policy, ast.ParserOptions{
+		ProcessAnnotation: true,
+	})
+	if err != nil {
+		return err
+	}
+
+	e.compiler.Compile(map[string]*ast.Module{
+		filename: module,
+	})
+
+	if e.compiler.Failed() {
+		return fmt.Errorf("compiler: %w", e.compiler.Errors)
+	}
+
+	e.modules[filename] = module
+
+	return nil
+}
+
 func (e *Engine) Check(ctx context.Context, namespace string, input interface{}) (output.Report, error) {
 	report, err := e.check(ctx, namespace, input)
 	if err != nil {

pkg/sdk/sdk.go

@@ -44,8 +44,8 @@ type Reposaur struct {
 //
 // The default HTTP client will use the default host `api.github.com`. Can
 // be customized using the `GITHUB_HOST` or `GH_HOST` environment variables.
-func New(ctx context.Context, policyPaths []string, opts ...Option) (*Reposaur, error) {
-	sdk := &Reposaur{
+func New(ctx context.Context, policyPaths []string, opts ...Option) (sdk *Reposaur, err error) {
+	sdk = &Reposaur{
 		logger: zerolog.New(os.Stderr),
 	}
 
@@ -66,11 +66,17 @@ func New(ctx context.Context, policyPaths []string, opts ...Option) (*Reposaur,
 	// to avoid unexpected side-effects by clients
 	builtins.RegisterBuiltins(sdk.httpClient)
 
-	var err error
+	engineOpts := []policy.EngineOption{
+		policy.WithTracingEnabled(sdk.enableTracing),
+	}
 
-	sdk.engine, err = policy.Load(ctx, policyPaths, policy.WithTracingEnabled(sdk.enableTracing))
-	if err != nil {
-		return nil, err
+	if len(policyPaths) == 0 {
+		sdk.engine = policy.NewEngine(engineOpts...)
+	} else {
+		sdk.engine, err = policy.NewEngineWithPolicies(ctx, policyPaths, engineOpts...)
+		if err != nil {
+			return nil, err
+		}
 	}
 
 	return sdk, nil