supports map of secrets; errors redact plaintext

Signed-off-by: Richard Jones <richard@dagger.io>

go.mod

@@ -25,6 +25,7 @@ require (
 	github.com/opencontainers/go-digest v1.0.0
 	github.com/opencontainers/image-spec v1.0.2
 	github.com/rs/zerolog v1.26.0
+	github.com/sergi/go-diff v1.1.0 // indirect
 	github.com/spf13/cobra v1.2.1
 	github.com/spf13/viper v1.8.1
 	github.com/stretchr/testify v1.7.0

pkg/dagger.io/dagger/engine/transformsecret.cue

@@ -5,13 +5,14 @@ package engine
 	$dagger: task: _name: "TransformSecret"
 	// The original secret
 	input: #Secret
-	// A new secret with the transformation applied
-	output: #Secret
+	// A new secret or (map of secrets) with the transformation applied
+	output: #Secret | {[string]: output}
 	// Transformation function
 	#function: {
 		// Full contents of the input secret (only available to the function)
-		input: string
+		input:           string
+		_functionOutput: string | {[string]: _functionOutput}
 		// New contents of the output secret (must provided by the caller)
-		output: string
+		output: _functionOutput
 	}
 }

plan/task/transformsecret.go

@@ -3,9 +3,11 @@ package task
 import (
 	"context"
 	"errors"
+	"strings"
 
 	"cuelang.org/go/cue"
 	"github.com/rs/zerolog/log"
+	"github.com/sergi/go-diff/diffmatchpatch"
 	"go.dagger.io/dagger/compiler"
 	"go.dagger.io/dagger/plancontext"
 	"go.dagger.io/dagger/solver"
@@ -23,9 +25,6 @@ func (c *transformSecretTask) Run(ctx context.Context, pctx *plancontext.Context
 	lg.Debug().Msg("transforming secret")
 
 	input := v.Lookup("input")
-	if !plancontext.IsSecretValue(input) {
-		return nil, errors.New("#TransformSecret requires input: #Secret")
-	}
 
 	inputSecret, err := pctx.Secrets.FromValue(input)
 	if err != nil {
@@ -33,15 +32,37 @@ func (c *transformSecretTask) Run(ctx context.Context, pctx *plancontext.Context
 	}
 
 	function := v.Lookup("#function")
-	function.FillPath(cue.ParsePath("input"), inputSecret.PlainText())
-
-	outputPlaintext, err := function.Lookup("output").String()
+	inputSecretPlaintext := inputSecret.PlainText()
+	err = function.FillPath(cue.ParsePath("input"), inputSecretPlaintext)
 	if err != nil {
-		return nil, err
+		dmp := diffmatchpatch.New()
+		errStr := err.Error()
+		diffs := dmp.DiffMain(inputSecretPlaintext, err.Error(), false)
+		for _, diff := range diffs {
+			if diff.Type == diffmatchpatch.DiffEqual {
+				diffText := strings.ReplaceAll(diff.Text, ":", "")
+				errStr = strings.ReplaceAll(errStr, diffText, "<redacted>")
+			}
+		}
+
+		return nil, errors.New(errStr)
 	}
 
-	outputSecret := pctx.Secrets.New(outputPlaintext)
-	return compiler.NewValue().FillFields(map[string]interface{}{
-		"output": outputSecret.MarshalCUE(),
+	output := compiler.NewValue()
+	// users could yaml.Unmarshal(input) and return a map
+	// or yaml.Unmarshal(input).someKey and return a string
+	// walk will ensure we convert every leaf
+	functionPathSelectors := function.Path().Selectors()
+	function.Lookup("output").Walk(nil, func(v *compiler.Value) {
+		if v.Kind() == cue.StringKind {
+			plaintext, _ := v.String()
+			secret := pctx.Secrets.New(plaintext)
+			newLeafSelectors := v.Path().Selectors()[len(functionPathSelectors):]
+			newLeafSelectors = append(newLeafSelectors, cue.Str("contents"))
+			newLeafPath := cue.MakePath(newLeafSelectors...)
+			output.FillPath(newLeafPath, secret.MarshalCUE())
+		}
 	})
+
+	return output, nil
 }

tests/tasks/build/build_auth.cue

@@ -19,7 +19,7 @@ engine.#Plan & {
 			input: inputs.secrets.sops.contents
 			#function: {
 				input:  _
-				output: yaml.Unmarshal(input).DOCKERHUB_TOKEN
+				output: yaml.Unmarshal(input)
 			}
 		}
 
@@ -29,7 +29,7 @@ engine.#Plan & {
 				target:   "daggerio/ci-test:private-pull"
 				username: "daggertest"
 
-				secret: dockerHubToken.output
+				secret: dockerHubToken.output.DOCKERHUB_TOKEN.contents
 			}]
 			dockerfile: contents: """
 				FROM daggerio/ci-test:private-pull@sha256:c74f1b1166784193ea6c8f9440263b9be6cae07dfe35e32a5df7a31358ac2060

tests/tasks/gitpull/private_repo.cue

@@ -21,7 +21,7 @@ engine.#Plan & {
 			input: inputs.secrets.sops.contents
 			#function: {
 				input:  _
-				output: yaml.Unmarshal(input).TestPAT
+				output: yaml.Unmarshal(input)
 			}
 		}
 
@@ -30,7 +30,7 @@ engine.#Plan & {
 			ref:    "main"
 			auth: {
 				username: "dagger-test"
-				password: repoPassword.output
+				password: repoPassword.output.TestPAT.contents
 			}
 		}