client: pass through the deployment directly

we can't serialize Cue in a lossless way. The current architecture has
the frontend serialize the state (plan, input, computed) to Cue files,
then the client loads them back. We lose information by doing this, and
therefore the merge fails.

This change removes the abstraction so that we operate directly on the
cue.Instance.

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

cmd/dagger/cmd/common/common.go

@@ -60,7 +60,7 @@ func GetCurrentDeploymentState(ctx context.Context, store *dagger.Store) *dagger
 }
 
 // Re-compute a deployment (equivalent to `dagger up`).
-func DeploymentUp(ctx context.Context, state *dagger.DeploymentState) *dagger.DeploymentResult {
+func DeploymentUp(ctx context.Context, state *dagger.DeploymentState) *dagger.Deployment {
 	lg := log.Ctx(ctx)
 
 	c, err := dagger.NewClient(ctx, "")

cmd/dagger/cmd/compute.go

@@ -7,9 +7,11 @@ import (
 	"os"
 	"strings"
 
+	"cuelang.org/go/cue"
 	"dagger.io/go/cmd/dagger/cmd/common"
 	"dagger.io/go/cmd/dagger/logger"
 	"dagger.io/go/dagger"
+	"dagger.io/go/dagger/compiler"
 	"go.mozilla.org/sops/v3"
 	"go.mozilla.org/sops/v3/decrypt"
 
@@ -128,14 +130,20 @@ var computeCmd = &cobra.Command{
 			}
 		}
 
-		result := common.DeploymentUp(ctx, st)
+		deployment := common.DeploymentUp(ctx, st)
 
-		cueVal, err := result.Merge()
+		v := compiler.NewValue()
-		if err != nil {
+		if err := v.FillPath(cue.MakePath(), deployment.Plan()); err != nil {
-			lg.Fatal().Err(err).Msg("failed to merge result")
+			lg.Fatal().Err(err).Msg("failed to merge")
+		}
+		if err := v.FillPath(cue.MakePath(), deployment.Input()); err != nil {
+			lg.Fatal().Err(err).Msg("failed to merge")
+		}
+		if err := v.FillPath(cue.MakePath(), deployment.Computed()); err != nil {
+			lg.Fatal().Err(err).Msg("failed to merge")
 		}
 
-		fmt.Println(cueVal.JSON())
+		fmt.Println(v.JSON())
 	},
 }
 

cmd/dagger/cmd/query.go

@@ -51,7 +51,8 @@ var queryCmd = &cobra.Command{
 		if err != nil {
 			lg.Fatal().Err(err).Msg("unable to create client")
 		}
-		result, err := c.Do(ctx, state, nil)
+
+		deployment, err := c.Do(ctx, state, nil)
 		if err != nil {
 			lg.Fatal().Err(err).Msg("failed to query deployment")
 		}
@@ -59,13 +60,13 @@ var queryCmd = &cobra.Command{
 		cueVal := compiler.NewValue()
 
 		if !viper.GetBool("no-plan") {
-			if err := cueVal.FillPath(cue.MakePath(), result.Plan()); err != nil {
+			if err := cueVal.FillPath(cue.MakePath(), deployment.Plan()); err != nil {
 				lg.Fatal().Err(err).Msg("failed to merge plan")
 			}
 		}
 
 		if !viper.GetBool("no-input") {
-			if err := cueVal.FillPath(cue.MakePath(), result.Input()); err != nil {
+			if err := cueVal.FillPath(cue.MakePath(), deployment.Input()); err != nil {
 				lg.Fatal().Err(err).Msg("failed to merge plan with output")
 			}
 		}

dagger/client.go

@@ -3,7 +3,6 @@ package dagger
 import (
 	"context"
 	"fmt"
-	"io"
 	"os"
 	"path/filepath"
 	"strings"
@@ -18,6 +17,7 @@ import (
 	// buildkit
 	bk "github.com/moby/buildkit/client"
 	_ "github.com/moby/buildkit/client/connhelper/dockercontainer" // import the container connection driver
+	"github.com/moby/buildkit/client/llb"
 	bkgw "github.com/moby/buildkit/frontend/gateway/client"
 
 	// docker output
@@ -60,7 +60,7 @@ func NewClient(ctx context.Context, host string) (*Client, error) {
 type ClientDoFunc func(context.Context, *Deployment, Solver) error
 
 // FIXME: return completed *Route, instead of *compiler.Value
-func (c *Client) Do(ctx context.Context, state *DeploymentState, fn ClientDoFunc) (*DeploymentResult, error) {
+func (c *Client) Do(ctx context.Context, state *DeploymentState, fn ClientDoFunc) (*Deployment, error) {
 	lg := log.Ctx(ctx)
 	eg, gctx := errgroup.WithContext(ctx)
 
@@ -79,25 +79,14 @@ func (c *Client) Do(ctx context.Context, state *DeploymentState, fn ClientDoFunc
 	})
 
 	// Spawn build function
-	outr, outw := io.Pipe()
 	eg.Go(func() error {
-		defer outw.Close()
+		return c.buildfn(gctx, deployment, fn, events)
-		return c.buildfn(gctx, deployment, fn, events, outw)
 	})
 
-	// Spawn output retriever
+	return deployment, eg.Wait()
-	var result *DeploymentResult
-	eg.Go(func() error {
-		defer outr.Close()
-
-		result, err = ReadDeploymentResult(gctx, outr)
-		return err
-	})
-
-	return result, eg.Wait()
 }
 
-func (c *Client) buildfn(ctx context.Context, deployment *Deployment, fn ClientDoFunc, ch chan *bk.SolveStatus, w io.WriteCloser) error {
+func (c *Client) buildfn(ctx context.Context, deployment *Deployment, fn ClientDoFunc, ch chan *bk.SolveStatus) error {
 	lg := log.Ctx(ctx)
 
 	// Scan local dirs to grant access
@@ -113,15 +102,6 @@ func (c *Client) buildfn(ctx context.Context, deployment *Deployment, fn ClientD
 	// Setup solve options
 	opts := bk.SolveOpt{
 		LocalDirs: localdirs,
-		// FIXME: catch output & return as cue value
-		Exports: []bk.ExportEntry{
-			{
-				Type: bk.ExporterTar,
-				Output: func(m map[string]string) (io.WriteCloser, error) {
-					return w, nil
-				},
-			},
-		},
 	}
 
 	// Call buildkit solver
@@ -151,11 +131,13 @@ func (c *Client) buildfn(ctx context.Context, deployment *Deployment, fn ClientD
 		span, _ := opentracing.StartSpanFromContext(ctx, "Deployment.Export")
 		defer span.Finish()
 
-		result := deployment.Result()
+		computed := deployment.Computed().JSON().PrettyString()
-		st, err := result.ToLLB()
+		st := llb.
-		if err != nil {
+			Scratch().
-			return nil, err
+			File(
-		}
+				llb.Mkfile("computed.json", 0600, []byte(computed)),
+				llb.WithCustomName("[internal] serializing computed values"),
+			)
 
 		ref, err := s.Solve(ctx, st)
 		if err != nil {

dagger/deployment.go

@@ -20,13 +20,24 @@ import (
 
 type Deployment struct {
 	state *DeploymentState
-	result *DeploymentResult
+
+	// Layer 1: plan configuration
+	plan *compiler.Value
+
+	// Layer 2: user inputs
+	input *compiler.Value
+
+	// Layer 3: computed values
+	computed *compiler.Value
 }
 
 func NewDeployment(st *DeploymentState) (*Deployment, error) {
 	d := &Deployment{
 		state: st,
-		result: NewDeploymentResult(),
+
+		plan:     compiler.NewValue(),
+		input:    compiler.NewValue(),
+		computed: compiler.NewValue(),
 	}
 
 	// Prepare inputs
@@ -36,9 +47,9 @@ func NewDeployment(st *DeploymentState) (*Deployment, error) {
 			return nil, err
 		}
 		if input.Key == "" {
-			err = d.result.input.FillPath(cue.MakePath(), v)
+			err = d.input.FillPath(cue.MakePath(), v)
 		} else {
-			err = d.result.input.FillPath(cue.ParsePath(input.Key), v)
+			err = d.input.FillPath(cue.ParsePath(input.Key), v)
 		}
 		if err != nil {
 			return nil, err
@@ -60,8 +71,16 @@ func (d *Deployment) PlanSource() Input {
 	return d.state.PlanSource
 }
 
-func (d *Deployment) Result() *DeploymentResult {
+func (d *Deployment) Plan() *compiler.Value {
-	return d.result
+	return d.plan
+}
+
+func (d *Deployment) Input() *compiler.Value {
+	return d.input
+}
+
+func (d *Deployment) Computed() *compiler.Value {
+	return d.computed
 }
 
 // LoadPlan loads the plan
@@ -89,7 +108,7 @@ func (d *Deployment) LoadPlan(ctx context.Context, s Solver) error {
 	if err != nil {
 		return fmt.Errorf("plan config: %w", err)
 	}
-	d.result.plan = plan
+	d.plan = plan
 
 	return nil
 }
@@ -122,7 +141,7 @@ func (d *Deployment) LocalDirs() map[string]string {
 	}
 	// 1. Scan the deployment state
 	// FIXME: use a common `flow` instance to avoid rescanning the tree.
-	src, err := d.result.Merge()
+	src, err := compiler.InstanceMerge(d.plan, d.input)
 	if err != nil {
 		panic(err)
 	}
@@ -151,10 +170,10 @@ func (d *Deployment) Up(ctx context.Context, s Solver) error {
 	defer span.Finish()
 
 	// Reset the computed values
-	d.result.computed = compiler.NewValue()
+	d.computed = compiler.NewValue()
 
 	// Cueflow cue instance
-	src, err := d.result.Merge()
+	src, err := compiler.InstanceMerge(d.plan, d.input)
 	if err != nil {
 		return err
 	}
@@ -163,7 +182,7 @@ func (d *Deployment) Up(ctx context.Context, s Solver) error {
 	flow := cueflow.New(
 		&cueflow.Config{},
 		src.CueInst(),
-		newTaskFunc(src.CueInst(), newPipelineRunner(src.CueInst(), d.result, s)),
+		newTaskFunc(src.CueInst(), newPipelineRunner(src.CueInst(), d.computed, s)),
 	)
 	if err := flow.Run(ctx); err != nil {
 		return err
@@ -195,7 +214,7 @@ func noOpRunner(t *cueflow.Task) error {
 	return nil
 }
 
-func newPipelineRunner(inst *cue.Instance, result *DeploymentResult, s Solver) cueflow.RunnerFunc {
+func newPipelineRunner(inst *cue.Instance, computed *compiler.Value, s Solver) cueflow.RunnerFunc {
 	return cueflow.RunnerFunc(func(t *cueflow.Task) error {
 		ctx := t.Context()
 		lg := log.
@@ -243,12 +262,11 @@ func newPipelineRunner(inst *cue.Instance, result *DeploymentResult, s Solver) c
 		}
 
 		// Mirror the computed values in both `Task` and `Result`
-		computed := p.Computed()
+		if p.Computed().IsEmptyStruct() {
-		if computed.IsEmptyStruct() {
 			return nil
 		}
 
-		if err := t.Fill(computed.Cue()); err != nil {
+		if err := t.Fill(p.Computed().Cue()); err != nil {
 			lg.
 				Error().
 				Err(err).
@@ -257,7 +275,7 @@ func newPipelineRunner(inst *cue.Instance, result *DeploymentResult, s Solver) c
 		}
 
 		// Merge task value into output
-		if err := result.computed.FillPath(t.Path(), computed); err != nil {
+		if err := computed.FillPath(t.Path(), p.Computed()); err != nil {
 			lg.
 				Error().
 				Err(err).

dagger/result.go

@@ -1,150 +0,0 @@
-package dagger
-
-import (
-	"archive/tar"
-	"context"
-	"errors"
-	"fmt"
-	"io"
-	"strings"
-
-	"dagger.io/go/dagger/compiler"
-	"github.com/moby/buildkit/client/llb"
-	"github.com/rs/zerolog/log"
-)
-
-const (
-	planFile     = "plan.cue"
-	inputFile    = "input.cue"
-	computedFile = "computed.cue"
-)
-
-// DeploymentResult represents the layers of a deployment run
-type DeploymentResult struct {
-	// Layer 1: plan configuration
-	plan *compiler.Value
-
-	// Layer 2: user inputs
-	input *compiler.Value
-
-	// Layer 3: computed values
-	computed *compiler.Value
-}
-
-func NewDeploymentResult() *DeploymentResult {
-	return &DeploymentResult{
-		plan:     compiler.NewValue(),
-		input:    compiler.NewValue(),
-		computed: compiler.NewValue(),
-	}
-}
-
-func (r *DeploymentResult) Plan() *compiler.Value {
-	return r.plan
-}
-
-func (r *DeploymentResult) Input() *compiler.Value {
-	return r.input
-}
-
-func (r *DeploymentResult) Computed() *compiler.Value {
-	return r.computed
-}
-
-func (r *DeploymentResult) Merge() (*compiler.Value, error) {
-	return compiler.InstanceMerge(
-		r.plan,
-		r.input,
-		r.computed,
-	)
-}
-
-func (r *DeploymentResult) ToLLB() (llb.State, error) {
-	st := llb.Scratch()
-
-	planSource, err := r.plan.Source()
-	if err != nil {
-		return st, compiler.Err(err)
-	}
-
-	inputSource, err := r.input.Source()
-	if err != nil {
-		return st, compiler.Err(err)
-	}
-
-	outputSource, err := r.computed.Source()
-	if err != nil {
-		return st, compiler.Err(err)
-	}
-
-	st = st.
-		File(
-			llb.Mkfile(planFile, 0600, planSource),
-			llb.WithCustomName("[internal] serializing plan"),
-		).
-		File(
-			llb.Mkfile(inputFile, 0600, inputSource),
-			llb.WithCustomName("[internal] serializing input"),
-		).
-		File(
-			llb.Mkfile(computedFile, 0600, outputSource),
-			llb.WithCustomName("[internal] serializing output"),
-		)
-
-	return st, nil
-}
-
-func ReadDeploymentResult(ctx context.Context, r io.Reader) (*DeploymentResult, error) {
-	lg := log.Ctx(ctx)
-	result := NewDeploymentResult()
-	tr := tar.NewReader(r)
-
-	for {
-		h, err := tr.Next()
-		if errors.Is(err, io.EOF) {
-			break
-		}
-		if err != nil {
-			return nil, fmt.Errorf("read tar stream: %w", err)
-		}
-
-		lg := lg.
-			With().
-			Str("file", h.Name).
-			Logger()
-
-		if !strings.HasSuffix(h.Name, ".cue") {
-			lg.Debug().Msg("skipping non-cue file from exporter tar stream")
-			continue
-		}
-
-		lg.Debug().Msg("outputfn: compiling")
-
-		src, err := io.ReadAll(tr)
-		if err != nil {
-			return nil, err
-		}
-
-		v, err := compiler.Compile(h.Name, src)
-		if err != nil {
-			lg.
-				Debug().
-				Err(compiler.Err(err)).
-				Bytes("src", src).
-				Msg("invalid result file")
-			return nil, fmt.Errorf("failed to compile result: %w", compiler.Err(err))
-		}
-
-		switch h.Name {
-		case planFile:
-			result.plan = v
-		case inputFile:
-			result.input = v
-		case computedFile:
-			result.computed = v
-		default:
-			lg.Warn().Msg("unexpected file")
-		}
-	}
-	return result, nil
-}