Passing StepResults between Steps

examples/v1/taskruns/alpha/stepaction-passing-results.yaml

@@ -0,0 +1,34 @@
+apiVersion: tekton.dev/v1alpha1
+kind: StepAction
+metadata:
+  name: step-action
+spec:
+  params:
+    - name: param1
+      type: array
+  image: bash:3.2
+  command: ["echo"]
+  args: [
+    "$(params.param1[*])",
+  ]
+---
+apiVersion: tekton.dev/v1
+kind: TaskRun
+metadata:
+  name: step-action-run
+spec:
+  TaskSpec:
+    steps:
+      - name: inline-step
+        results:
+          - name: result1
+            type: array
+        image: alpine
+        script: |
+          echo -n "[\"image1\", \"image2\", \"image3\"]" | tee $(step.results.result1.path)
+      - name: action-runner
+        ref:
+          name: step-action
+        params:
+          - name: param1
+            value: $(steps.inline-step.results.result1[*])

pkg/apis/pipeline/v1/pipeline_validation.go

@@ -684,7 +684,7 @@ func taskContainsResult(resultExpression string, pipelineTaskNames sets.String,
 	for _, expression := range split {
 		if expression != "" {
 			value := stripVarSubExpression("$" + expression)
-			pipelineTaskName, _, _, _, err := parseExpression(value)
+			pipelineTaskName, _, _, _, _, err := parseExpression(value)
 
 			if err != nil {
 				return false

pkg/apis/pipeline/v1/resultref.go

@@ -37,6 +37,8 @@ const (
 	// If a string result name contains a dot, brackets should be used to differentiate it from an object result.
 	// https://github.com/tektoncd/community/blob/main/teps/0075-object-param-and-result-types.md#collisions-with-builtin-variable-replacement
 	objectResultExpressionFormat = "tasks.<taskName>.results.<objectResultName>.<individualAttribute>"
+	// ResultStepPart Constant used to define the "steps" part of a step result reference
+	ResultStepPart = "steps"
 	// ResultTaskPart Constant used to define the "tasks" part of a pipeline result reference
 	ResultTaskPart = "tasks"
 	// ResultFinallyPart Constant used to define the "finally" part of a pipeline result reference
@@ -69,9 +71,9 @@ var arrayIndexingRegex = regexp.MustCompile(arrayIndexing)
 func NewResultRefs(expressions []string) []*ResultRef {
 	var resultRefs []*ResultRef
 	for _, expression := range expressions {
-		pipelineTask, result, index, property, err := parseExpression(expression)
+		pipelineTask, result, index, property, _, err := parseTaskExpression(expression)
 		// If the expression isn't a result but is some other expression,
-		// parseExpression will return an error, in which case we just skip that expression,
+		// parseTaskExpression will return an error, in which case we just skip that expression,
 		// since although it's not a result ref, it might be some other kind of reference
 		if err == nil {
 			resultRefs = append(resultRefs, &ResultRef{
@@ -105,6 +107,13 @@ func looksLikeResultRef(expression string) bool {
 	return len(subExpressions) >= 4 && (subExpressions[0] == ResultTaskPart || subExpressions[0] == ResultFinallyPart) && subExpressions[2] == ResultResultPart
 }
 
+// looksLikeStepResultRef attempts to check if the given string looks like it contains any
+// step result references. Returns true if it does, false otherwise
+func looksLikeStepResultRef(expression string) bool {
+	subExpressions := strings.Split(expression, ".")
+	return len(subExpressions) >= 4 && subExpressions[0] == ResultStepPart && subExpressions[2] == ResultResultPart
+}
+
 func validateString(value string) []string {
 	expressions := VariableSubstitutionRegex.FindAllString(value, -1)
 	if expressions == nil {
@@ -121,38 +130,62 @@ func stripVarSubExpression(expression string) string {
 	return strings.TrimSuffix(strings.TrimPrefix(expression, "$("), ")")
 }
 
-// parseExpression parses "task name", "result name", "array index" (iff it's an array result) and "object key name" (iff it's an object result)
+// parseExpression parses "task name" or "step name" , "result name", "array index" (iff it's an array result) and "object key name" (iff it's an object result)
 // Valid Example 1:
 // - Input: tasks.myTask.results.aStringResult
 // - Output: "myTask", "aStringResult", -1, "", nil
+// - Input: steps.myStep.results.aStringResult
+// - Output: "myStep", "aStringResult", -1, "", nil
 // Valid Example 2:
 // - Input: tasks.myTask.results.anObjectResult.key1
 // - Output: "myTask", "anObjectResult", 0, "key1", nil
+// - Input: steps.myStep.results.anObjectResult.key1
+// - Output: "myStep", "anObjectResult", 0, "key1", nil
 // Valid Example 3:
 // - Input: tasks.myTask.results.anArrayResult[1]
 // - Output: "myTask", "anArrayResult", 1, "", nil
+// - Input: steps.myStep.results.anArrayResult[1]
+// - Output: "myStep", "anArrayResult", 1, "", nil
 // Invalid Example 1:
 // - Input: tasks.myTask.results.resultName.foo.bar
 // - Output: "", "", 0, "", error
+// - Input: steps.myStep.results.resultName.foo.bar
+// - Output: "", "", 0, "", error
 // TODO: may use regex for each type to handle possible reference formats
-func parseExpression(substitutionExpression string) (string, string, int, string, error) {
-	if looksLikeResultRef(substitutionExpression) {
-		subExpressions := strings.Split(substitutionExpression, ".")
-		// For string result: tasks.<taskName>.results.<stringResultName>
-		// For array result: tasks.<taskName>.results.<arrayResultName>[index]
-		if len(subExpressions) == 4 {
-			resultName, stringIdx := ParseResultName(subExpressions[3])
-			if stringIdx != "" {
-				intIdx, _ := strconv.Atoi(stringIdx)
-				return subExpressions[1], resultName, intIdx, "", nil
+func parseExpression(substitutionExpression string) (string, string, int, string, ParamType, error) {
+	subExpressions := strings.Split(substitutionExpression, ".")
+	// For string result: tasks.<taskName>.results.<stringResultName> or steps.<stepName>.results.<stringResultName>
+	// For array result: tasks.<taskName>.results.<arrayResultName>[index] or steps.<stepName>.results.<arrayResultName>[index]
+	if len(subExpressions) == 4 {
+		resultName, stringIdx := ParseResultName(subExpressions[3])
+		if stringIdx != "" {
+			if stringIdx == "*" {
+				return subExpressions[1], resultName, -1, "", ParamTypeArray, nil
 			}
-			return subExpressions[1], resultName, 0, "", nil
-		} else if len(subExpressions) == 5 {
-			// For object type result: tasks.<taskName>.results.<objectResultName>.<individualAttribute>
-			return subExpressions[1], subExpressions[3], 0, subExpressions[4], nil
+			intIdx, _ := strconv.Atoi(stringIdx)
+			return subExpressions[1], resultName, intIdx, "", ParamTypeArray, nil
 		}
+		return subExpressions[1], resultName, 0, "", ParamTypeString, nil
+	} else if len(subExpressions) == 5 {
+		// For object type result: tasks.<taskName>.results.<objectResultName>.<individualAttribute>
+		// or steps.<stepName>.results.<objectResultName>.<individualAttribute>
+		return subExpressions[1], subExpressions[3], 0, subExpressions[4], ParamTypeObject, nil
+	}
+	return "", "", 0, "", ParamTypeString, fmt.Errorf("must be one of the form 1). %q; 2). %q", resultExpressionFormat, objectResultExpressionFormat)
+}
+
+func parseTaskExpression(substitutionExpression string) (string, string, int, string, ParamType, error) {
+	if looksLikeResultRef(substitutionExpression) {
+		return parseExpression(substitutionExpression)
+	}
+	return "", "", 0, "", ParamTypeString, fmt.Errorf("must be one of the form 1). %q; 2). %q", resultExpressionFormat, objectResultExpressionFormat)
+}
+
+func ParseStepExpression(substitutionExpression string) (string, string, int, string, ParamType, error) {
+	if looksLikeStepResultRef(substitutionExpression) {
+		return parseExpression(substitutionExpression)
 	}
-	return "", "", 0, "", fmt.Errorf("must be one of the form 1). %q; 2). %q", resultExpressionFormat, objectResultExpressionFormat)
+	return "", "", 0, "", ParamTypeString, fmt.Errorf("must be one of the form 1). %q; 2). %q", resultExpressionFormat, objectResultExpressionFormat)
 }
 
 // ParseResultName parse the input string to extract resultName and result index.

pkg/entrypoint/entrypointer.go

@@ -24,13 +24,15 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"regexp"
 	"strconv"
 	"strings"
 	"syscall"
 	"time"
 
 	"github.com/tektoncd/pipeline/pkg/apis/config"
 	"github.com/tektoncd/pipeline/pkg/apis/pipeline"
+	v1 "github.com/tektoncd/pipeline/pkg/apis/pipeline/v1"
 	"github.com/tektoncd/pipeline/pkg/pod"
 	"github.com/tektoncd/pipeline/pkg/result"
 	"github.com/tektoncd/pipeline/pkg/spire"
@@ -182,6 +184,9 @@ func (e Entrypointer) Go() error {
 	ctx := context.Background()
 	var cancel context.CancelFunc
 	if err == nil {
+		if err := e.applyStepResultSubstitutions(); err != nil {
+			logger.Error("Error while substituting step results: ", err)
+		}
 		ctx, cancel = context.WithCancel(ctx)
 		if e.Timeout != nil && *e.Timeout > time.Duration(0) {
 			ctx, cancel = context.WithTimeout(ctx, *e.Timeout)
@@ -336,3 +341,118 @@ func (e Entrypointer) waitingCancellation(ctx context.Context, cancel context.Ca
 	cancel()
 	return nil
 }
+
+// loadStepResult reads the step result file and returns the string, array or object result value.
+func loadStepResult(stepName string, resultName string) (v1.ResultValue, error) {
+	v := v1.ResultValue{}
+	fileContents, err := os.ReadFile(getStepResultPath(pod.GetContainerName(stepName), resultName))
+	if err != nil {
+		return v, err
+	}
+	err = v.UnmarshalJSON(fileContents)
+	if err != nil {
+		return v, err
+	}
+	return v, nil
+}
+
+// getStepResultPath gets the path to the step result
+func getStepResultPath(stepName string, resultName string) string {
+	return filepath.Join(pipeline.StepsDir, stepName, "results", resultName)
+}
+
+func findReplacement(s string) (string, []string, error) {
+	value := strings.TrimSuffix(strings.TrimPrefix(s, "$("), ")")
+	stepName, resultName, arrayIdx, objectKey, paramType, err := v1.ParseStepExpression(value)
+	if err != nil {
+		return "", nil, err
+	}
+	result, err := loadStepResult(stepName, resultName)
+	if err != nil {
+		return "", nil, err
+	}
+	replaceWithArray := []string{}
+	replaceWithString := ""
+	if paramType == v1.ParamTypeObject && objectKey != "" {
+		replaceWithString = result.ObjectVal[objectKey]
+	} else if paramType == v1.ParamTypeArray {
+		if arrayIdx == -1 {
+			replaceWithArray = append(replaceWithArray, result.ArrayVal...)
+		} else {
+			replaceWithString = result.ArrayVal[arrayIdx]
+		}
+	} else {
+		replaceWithString = result.StringVal
+	}
+	return replaceWithString, replaceWithArray, nil
+}
+
+// applyStepResultSubstitutions applies the runtime step result substitutions in env.
+func (e *Entrypointer) applyStepResultSubstitutions() error {
+	pattern := `\$\(steps\..*\.results\..*\)`
+	stepResultRegex := regexp.MustCompile(pattern)
+	// env
+	for _, e := range os.Environ() {
+		pair := strings.SplitN(e, "=", 2)
+		matches := stepResultRegex.FindAllStringSubmatch(pair[1], -1)
+		for _, m := range matches {
+			replaceWith, _, err := findReplacement(m[0])
+			if err != nil {
+				return err
+			}
+			os.Setenv(pair[0], strings.ReplaceAll(pair[1], m[0], replaceWith))
+		}
+	}
+	// script
+	if strings.HasPrefix(e.Command[0], "/tekton/scripts") {
+		fileContentBytes, err := os.ReadFile(e.Command[0])
+		if err != nil {
+			return err
+		}
+		fileContents := string(fileContentBytes)
+		matches := stepResultRegex.FindAllStringSubmatch(fileContents, -1)
+		if len(matches) > 0 {
+			for _, m := range matches {
+				replaceWith, _, err := findReplacement(m[0])
+				if err != nil {
+					return err
+				}
+				fileContents = strings.ReplaceAll(fileContents, m[0], replaceWith)
+			}
+			// copy the modified contents to a different file.
+			newFilePath := filepath.Join(e.StepMetadataDir, "script")
+			err := os.WriteFile(newFilePath, []byte(fileContents), 0755)
+			if err != nil {
+				return err
+			}
+			// set the command to execute the new file.
+			e.Command[0] = newFilePath
+		}
+	}
+	// command + args
+	newCommand := []string{}
+	for _, c := range e.Command {
+		matches := stepResultRegex.FindAllStringSubmatch(c, -1)
+		if len(matches) > 0 {
+			for _, m := range matches {
+				replaceWithString, replaceWithArray, err := findReplacement(m[0])
+				if err != nil {
+					return err
+				}
+				// if replacing with an array
+				if len(replaceWithArray) > 1 {
+					// append with the array items
+					newCommand = append(newCommand, replaceWithArray...)
+				} else {
+					// append with replaced string
+					c = strings.ReplaceAll(c, m[0], replaceWithString)
+					newCommand = append(newCommand, c)
+				}
+			}
+		} else {
+			newCommand = append(newCommand, c)
+		}
+	}
+	e.Command = newCommand
+	return nil
+}

pkg/pod/entrypoint.go

@@ -353,11 +353,11 @@ func TrimSidecarPrefix(name string) string { return strings.TrimPrefix(name, sid
 // returns "step-unnamed-<step-index>" if not specified
 func StepName(name string, i int) string {
 	if name != "" {
-		return getContainerName(name)
+		return GetContainerName(name)
 	}
 	return fmt.Sprintf("%sunnamed-%d", stepPrefix, i)
 }
 
-func getContainerName(name string) string {
+func GetContainerName(name string) string {
 	return fmt.Sprintf("%s%s", stepPrefix, name)
 }

pkg/pod/status.go

@@ -247,7 +247,7 @@ func setTaskRunStatusBasedOnStepStatus(ctx context.Context, logger *zap.SugaredL
 		stepResults := []v1.StepResult{}
 		if ts != nil {
 			for _, step := range ts.Steps {
-				if getContainerName(step.Name) == s.Name {
+				if GetContainerName(step.Name) == s.Name {
 					stepResults = append(stepResults, step.Results...)
 				}
 			}
@@ -359,7 +359,7 @@ func findStepResultsFetchedByTask(containerName string, specResults []v1.TaskRes
 					return nil, err
 				}
 				// Only look at named results - referencing unnamed steps is unsupported.
-				if getContainerName(sName) == containerName {
+				if GetContainerName(sName) == containerName {
 					neededStepResults[resultName] = r.Name
 				}
 			}