solver/client: add ability to disable the cache at the LLB level

Signed-off-by: Sam Alba <sam.alba@gmail.com>

dagger/client.go

@@ -30,9 +30,10 @@ import (
 // A dagger client
 type Client struct {
 	c       *bk.Client
+	noCache bool
 }
 
-func NewClient(ctx context.Context, host string) (*Client, error) {
+func NewClient(ctx context.Context, host string, noCache bool) (*Client, error) {
 	if host == "" {
 		host = os.Getenv("BUILDKIT_HOST")
 	}
@@ -54,6 +55,7 @@ func NewClient(ctx context.Context, host string) (*Client, error) {
 	}
 	return &Client{
 		c:       c,
+		noCache: noCache,
 	}, nil
 }
 
@@ -111,7 +113,7 @@ func (c *Client) buildfn(ctx context.Context, deployment *Deployment, fn ClientD
 		Msg("spawning buildkit job")
 
 	resp, err := c.c.Build(ctx, opts, "", func(ctx context.Context, gw bkgw.Client) (*bkgw.Result, error) {
-		s := NewSolver(c.c, gw, ch)
+		s := NewSolver(c.c, gw, ch, c.noCache)
 
 		lg.Debug().Msg("loading configuration")
 		if err := deployment.LoadPlan(ctx, s); err != nil {

dagger/solver.go

@@ -14,6 +14,7 @@ import (
 	bkgw "github.com/moby/buildkit/frontend/gateway/client"
 	"github.com/moby/buildkit/session"
 	"github.com/moby/buildkit/session/auth/authprovider"
+	"github.com/moby/buildkit/solver/pb"
 	bkpb "github.com/moby/buildkit/solver/pb"
 	"github.com/opencontainers/go-digest"
 	"github.com/rs/zerolog/log"
@@ -23,22 +24,50 @@ type Solver struct {
 	events  chan *bk.SolveStatus
 	control *bk.Client
 	gw      bkgw.Client
+	noCache bool
 }
 
-func NewSolver(control *bk.Client, gw bkgw.Client, events chan *bk.SolveStatus) Solver {
+func NewSolver(control *bk.Client, gw bkgw.Client, events chan *bk.SolveStatus, noCache bool) Solver {
 	return Solver{
 		events:  events,
 		control: control,
 		gw:      gw,
+		noCache: noCache,
 	}
 }
 
+func invalidateCache(def *llb.Definition) error {
+	for _, dt := range def.Def {
+		var op pb.Op
+		if err := (&op).Unmarshal(dt); err != nil {
+			return err
+		}
+		dgst := digest.FromBytes(dt)
+		opMetadata, ok := def.Metadata[dgst]
+		if !ok {
+			opMetadata = pb.OpMetadata{}
+		}
+		c := llb.Constraints{Metadata: opMetadata}
+		llb.IgnoreCache(&c)
+		def.Metadata[dgst] = c.Metadata
+	}
+
+	return nil
+}
+
 func (s Solver) Marshal(ctx context.Context, st llb.State) (*bkpb.Definition, error) {
 	// FIXME: do not hardcode the platform
 	def, err := st.Marshal(ctx, llb.LinuxAmd64)
 	if err != nil {
 		return nil, err
 	}
+
+	if s.noCache {
+		if err := invalidateCache(def); err != nil {
+			return nil, err
+		}
+	}
+
 	return def.ToPB(), nil
 }