Add new Client API

Signed-off-by: Helder Correia <174525+helderco@users.noreply.github.com>

plan/task/task.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"strings"
 	"sync"
 
 	"cuelang.org/go/cue"
@@ -20,6 +21,10 @@ var (
 		cue.Str("$dagger"),
 		cue.Str("task"),
 		cue.Hid("_name", pkg.DaggerPackage))
+	lookups = []LookupFunc{
+		defaultLookup,
+		pathLookup,
+	}
 )
 
 // State is the state of the task.
@@ -33,6 +38,7 @@ const (
 )
 
 type NewFunc func() Task
+type LookupFunc func(*compiler.Value) (Task, error)
 
 type Task interface {
 	Run(ctx context.Context, pctx *plancontext.Context, s solver.Solver, v *compiler.Value) (*compiler.Value, error)
@@ -60,13 +66,26 @@ func New(typ string) Task {
 }
 
 func Lookup(v *compiler.Value) (Task, error) {
+	for _, lookup := range lookups {
+		t, err := lookup(v)
+		if err != nil {
+			return nil, err
+		}
+		if t != nil {
+			return t, nil
+		}
+	}
+	return nil, ErrNotTask
+}
+
+func defaultLookup(v *compiler.Value) (Task, error) {
 	if v.Kind() != cue.StructKind {
-		return nil, ErrNotTask
+		return nil, nil
 	}
 
 	typ := v.LookupPath(typePath)
 	if !typ.Exists() {
-		return nil, ErrNotTask
+		return nil, nil
 	}
 
 	typeString, err := typ.String()
@@ -78,5 +97,49 @@ func Lookup(v *compiler.Value) (Task, error) {
 	if t == nil {
 		return nil, fmt.Errorf("unknown type %q", typeString)
 	}
+
 	return t, nil
 }
+
+func pathLookup(v *compiler.Value) (Task, error) {
+	selectors := v.Path().Selectors()
+
+	// The `actions` field won't have any path based tasks since it's in user land
+	if len(selectors) == 0 || selectors[0].String() == "actions" {
+		return nil, nil
+	}
+
+	// Try an exact match first
+	if t := New(v.Path().String()); t != nil {
+		return t, nil
+	}
+
+	// FIXME: is there a way to avoid having to loop here?
+	var t Task
+	tasks.Range(func(key, value interface{}) bool {
+		if matchPathMask(selectors, key.(string)) {
+			fn := value.(NewFunc)
+			t = fn()
+			return false
+		}
+		return true
+	})
+	return t, nil
+}
+
+func matchPathMask(sels []cue.Selector, mask string) bool {
+	parts := strings.Split(mask, ".")
+	if len(sels) != len(parts) {
+		return false
+	}
+	for i, sel := range sels {
+		// use a '*' in a path mask part to match any selector
+		if parts[i] == "*" {
+			continue
+		}
+		if sel.String() != parts[i] {
+			return false
+		}
+	}
+	return true
+}