TEP-0142: Surface step results via sidecar logs

Prior to this, we enabled surfacing step results via termination message. This PR does the same thing via sidecar logs.

cmd/sidecarlogresults/main.go

@@ -17,6 +17,7 @@ limitations under the License.
 package main
 
 import (
+	"encoding/json"
 	"flag"
 	"log"
 	"os"
@@ -30,14 +31,20 @@ import (
 func main() {
 	var resultsDir string
 	var resultNames string
+	var stepResultsStr string
 	flag.StringVar(&resultsDir, "results-dir", pipeline.DefaultResultPath, "Path to the results directory. Default is /tekton/results")
 	flag.StringVar(&resultNames, "result-names", "", "comma separated result names to expect from the steps running in the pod. eg. foo,bar,baz")
+	flag.StringVar(&stepResultsStr, "step-results", "", "json containing a map of step Name as key and list of result Names. eg. {\"stepName\":[\"foo\",\"bar\",\"baz\"]}")
 	flag.Parse()
 	if resultNames == "" {
 		log.Fatal("result-names were not provided")
 	}
 	expectedResults := strings.Split(resultNames, ",")
-	err := sidecarlogresults.LookForResults(os.Stdout, pod.RunDir, resultsDir, expectedResults)
+	expectedStepResults := map[string][]string{}
+	if err := json.Unmarshal([]byte(stepResultsStr), &expectedStepResults); err != nil {
+		log.Fatal(err)
+	}
+	err := sidecarlogresults.LookForResults(os.Stdout, pod.RunDir, resultsDir, expectedResults, expectedStepResults)
 	if err != nil {
 		log.Fatal(err)
 	}

examples/v1/taskruns/no-ci/stepaction-results.yaml

@@ -6,8 +6,10 @@ spec:
   image: alpine
   results:
     - name: result1
+    - name: result2
   script: |
     echo "I am a Step Action!!!" >> $(step.results.result1.path)
+    echo "I am a hidden step action!!!" >> $(step.results.result2.path)
 ---
 apiVersion: tekton.dev/v1
 kind: TaskRun

internal/sidecarlogresults/sidecarlogresults.go

@@ -25,8 +25,10 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"github.com/tektoncd/pipeline/pkg/apis/config"
+	"github.com/tektoncd/pipeline/pkg/apis/pipeline"
 	"github.com/tektoncd/pipeline/pkg/result"
 	"golang.org/x/sync/errgroup"
 	corev1 "k8s.io/api/core/v1"
@@ -36,10 +38,19 @@ import (
 // ErrSizeExceeded indicates that the result exceeded its maximum allowed size
 var ErrSizeExceeded = errors.New("results size exceeds configured limit")
 
+type SidecarLogResultType string
+
+const (
+	taskResultType             SidecarLogResultType = "task"
+	stepResultType             SidecarLogResultType = "step"
+	sidecarResultNameSeparator string               = "."
+)
+
 // SidecarLogResult holds fields for storing extracted results
 type SidecarLogResult struct {
 	Name  string
 	Value string
+	Type  SidecarLogResultType
 }
 
 func fileExists(filename string) (bool, error) {
@@ -89,33 +100,79 @@ func waitForStepsToFinish(runDir string) error {
 	return nil
 }
 
+func createSidecarResultName(stepName, resultName string) string {
+	return fmt.Sprintf("%s%s%s", stepName, sidecarResultNameSeparator, resultName)
+}
+
+func ExtractStepAndResultFromSidecarResultName(sidecarResultName string) (string, string) {
+	splitString := strings.SplitN(sidecarResultName, sidecarResultNameSeparator, 2)
+	return splitString[0], splitString[1]
+}
+
+func readResults(resultsDir, resultFile, stepName string, resultType SidecarLogResultType) (SidecarLogResult, error) {
+	value, err := os.ReadFile(filepath.Join(resultsDir, resultFile))
+	if os.IsNotExist(err) {
+		return SidecarLogResult{}, nil
+	} else if err != nil {
+		return SidecarLogResult{}, fmt.Errorf("error reading the results file %w", err)
+	}
+	resultName := resultFile
+	if resultType == stepResultType {
+		resultName = createSidecarResultName(stepName, resultFile)
+	}
+	return SidecarLogResult{
+		Name:  resultName,
+		Value: string(value),
+		Type:  resultType,
+	}, nil
+}
+
 // LookForResults waits for results to be written out by the steps
 // in their results path and prints them in a structured way to its
 // stdout so that the reconciler can parse those logs.
-func LookForResults(w io.Writer, runDir string, resultsDir string, resultNames []string) error {
+func LookForResults(w io.Writer, runDir string, resultsDir string, resultNames []string, stepResults map[string][]string) error {
 	if err := waitForStepsToFinish(runDir); err != nil {
 		return fmt.Errorf("error while waiting for the steps to finish  %w", err)
 	}
 	results := make(chan SidecarLogResult)
 	g := new(errgroup.Group)
 	for _, resultFile := range resultNames {
-		resultFile := resultFile
+		resultFile := filepath.Join(resultsDir, resultFile)
 
 		g.Go(func() error {
-			value, err := os.ReadFile(filepath.Join(resultsDir, resultFile))
-			if os.IsNotExist(err) {
-				return nil
-			} else if err != nil {
-				return fmt.Errorf("error reading the results file %w", err)
+			newResult, err := readResults(resultsDir, resultFile, "", taskResultType)
+			if err != nil {
+				return err
 			}
-			newResult := SidecarLogResult{
-				Name:  resultFile,
-				Value: string(value),
+			if newResult.Name == "" {
+				return nil
 			}
 			results <- newResult
 			return nil
 		})
 	}
+
+	for sName, sresults := range stepResults {
+		sresults := sresults
+		sName := sName
+		for _, resultName := range sresults {
+			resultName := resultName
+			stepResultsDir := filepath.Join(pipeline.StepsDir, sName, "results")
+
+			g.Go(func() error {
+				newResult, err := readResults(stepResultsDir, resultName, sName, stepResultType)
+				if err != nil {
+					return err
+				}
+				if newResult.Name == "" {
+					return nil
+				}
+				results <- newResult
+				return nil
+			})
+		}
+	}
+
 	channelGroup := new(errgroup.Group)
 	channelGroup.Go(func() error {
 		if err := g.Wait(); err != nil {
@@ -183,10 +240,19 @@ func parseResults(resultBytes []byte, maxResultLimit int) (result.RunResult, err
 	if len(resultBytes) > maxResultLimit {
 		return runResult, fmt.Errorf("invalid result \"%s\": %w of %d", res.Name, ErrSizeExceeded, maxResultLimit)
 	}
+	var resultType result.ResultType
+	switch res.Type {
+	case taskResultType:
+		resultType = result.TaskRunResultType
+	case stepResultType:
+		resultType = result.StepResultType
+	default:
+		return result.RunResult{}, fmt.Errorf("Invalid sidecar result type %v. Must be %v or %v", res.Type, taskResultType, stepResultType)
+	}
 	runResult = result.RunResult{
 		Key:        res.Name,
 		Value:      res.Value,
-		ResultType: result.TaskRunResultType,
+		ResultType: resultType,
 	}
 	return runResult, nil
 }

pkg/pod/pod.go

@@ -18,6 +18,7 @@ package pod
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"log"
 	"math"
@@ -190,7 +191,10 @@ func (b *Builder) Build(ctx context.Context, taskRun *v1.TaskRun, taskSpec v1.Ta
 	windows := usesWindows(taskRun)
 	if sidecarLogsResultsEnabled && taskSpec.Results != nil {
 		// create a results sidecar
-		resultsSidecar := createResultsSidecar(taskSpec, b.Images.SidecarLogResultsImage, setSecurityContext, windows)
+		resultsSidecar, err := createResultsSidecar(taskSpec, b.Images.SidecarLogResultsImage, setSecurityContext, windows)
+		if err != nil {
+			return nil, err
+		}
 		taskSpec.Sidecars = append(taskSpec.Sidecars, resultsSidecar)
 		commonExtraEntrypointArgs = append(commonExtraEntrypointArgs, "-result_from", config.ResultExtractionMethodSidecarLogs)
 	}
@@ -568,26 +572,46 @@ func entrypointInitContainer(image string, steps []v1.Step, setSecurityContext,
 // based on the spec of the Task, the image that should run in the results sidecar,
 // whether it will run on a windows node, and whether the sidecar should include a security context
 // that will allow it to run in namespaces with "restricted" pod security admission.
-func createResultsSidecar(taskSpec v1.TaskSpec, image string, setSecurityContext, windows bool) v1.Sidecar {
+func createResultsSidecar(taskSpec v1.TaskSpec, image string, setSecurityContext, windows bool) (v1.Sidecar, error) {
 	names := make([]string, 0, len(taskSpec.Results))
 	for _, r := range taskSpec.Results {
 		names = append(names, r.Name)
 	}
-	securityContext := linuxSecurityContext
-	if windows {
-		securityContext = windowsSecurityContext
-	}
 	resultsStr := strings.Join(names, ",")
 	command := []string{"/ko-app/sidecarlogresults", "-results-dir", pipeline.DefaultResultPath, "-result-names", resultsStr}
+
+	// create a map of container Name to step results
+	stepResults := map[string][]string{}
+	for i, s := range taskSpec.Steps {
+		if len(s.Results) > 0 {
+			stepName := StepName(s.Name, i)
+			stepResults[stepName] = make([]string, 0, len(s.Results))
+			for _, r := range s.Results {
+				stepResults[stepName] = append(stepResults[stepName], r.Name)
+			}
+		}
+	}
+
+	stepResultsBytes, err := json.Marshal(stepResults)
+	if err != nil {
+		return v1.Sidecar{}, err
+	}
+	if len(stepResultsBytes) > 0 {
+		command = append(command, "-step-results", string(stepResultsBytes))
+	}
 	sidecar := v1.Sidecar{
 		Name:    pipeline.ReservedResultsSidecarName,
 		Image:   image,
 		Command: command,
 	}
+	securityContext := linuxSecurityContext
+	if windows {
+		securityContext = windowsSecurityContext
+	}
 	if setSecurityContext {
 		sidecar.SecurityContext = securityContext
 	}
-	return sidecar
+	return sidecar, nil
 }
 
 // usesWindows returns true if the TaskRun will run on a windows node,