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Refactor Sidecar Containers Construction If Script Exists #6619

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merged 1 commit into from
May 5, 2023
Merged

Refactor Sidecar Containers Construction If Script Exists #6619

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211 changes: 112 additions & 99 deletions pkg/pod/script.go
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Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,6 @@ import (
"github.com/tektoncd/pipeline/pkg/apis/pipeline/v1beta1"
"github.com/tektoncd/pipeline/pkg/names"
corev1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)

const (
Expand Down Expand Up @@ -71,7 +70,6 @@ var (

// convertScripts converts any steps and sidecars that specify a Script field into a normal Container.
func convertScripts(shellImageLinux string, shellImageWin string, steps []v1beta1.Step, sidecars []v1beta1.Sidecar, debugConfig *v1beta1.TaskRunDebug) (*corev1.Container, []corev1.Container, []corev1.Container) {
placeScripts := false
// Place scripts is an init container used for creating scripts in the
// /tekton/scripts directory which would be later used by the step containers
// as a Command
Expand All @@ -96,144 +94,159 @@ func convertScripts(shellImageLinux string, shellImageWin string, steps []v1beta
}

breakpoints := []string{}
sideCarSteps := []v1beta1.Step{}
for _, sidecar := range sidecars {
c := sidecar.ToK8sContainer()
sidecarStep := v1beta1.Step{
Script: sidecar.Script,
Timeout: &metav1.Duration{},
}
sidecarStep.SetContainerFields(*c)
sideCarSteps = append(sideCarSteps, sidecarStep)
}

// Add mounts for debug
if debugConfig != nil && len(debugConfig.Breakpoint) > 0 {
breakpoints = debugConfig.Breakpoint
placeScriptsInit.VolumeMounts = append(placeScriptsInit.VolumeMounts, debugScriptsVolumeMount)
}

convertedStepContainers := convertListOfSteps(steps, &placeScriptsInit, &placeScripts, breakpoints, "script")
convertedStepContainers := convertListOfSteps(steps, &placeScriptsInit, breakpoints, "script")
sidecarContainers := convertListOfSidecars(sidecars, &placeScriptsInit, "sidecar-script")

// Pass empty breakpoint list in "sidecar step to container" converter to not rewrite the scripts and add breakpoints to sidecar
sidecarContainers := convertListOfSteps(sideCarSteps, &placeScriptsInit, &placeScripts, []string{}, "sidecar-script")
if placeScripts {
if hasScripts(steps, sidecars, breakpoints) {
return &placeScriptsInit, convertedStepContainers, sidecarContainers
}
return nil, convertedStepContainers, sidecarContainers
}

// convertListOfSteps does the heavy lifting for convertScripts.
//
// It iterates through the list of steps (or sidecars), generates the script file name and heredoc termination string,
// convertListOfSidecars iterates through the list of sidecars, generates the script file name and heredoc termination string,
// adds an entry to the init container args, sets up the step container to run the script, and sets the volume mounts.
func convertListOfSteps(steps []v1beta1.Step, initContainer *corev1.Container, placeScripts *bool, breakpoints []string, namePrefix string) []corev1.Container {
func convertListOfSidecars(sidecars []v1beta1.Sidecar, initContainer *corev1.Container, namePrefix string) []corev1.Container {
containers := []corev1.Container{}
for i, s := range steps {
// Add debug mounts if breakpoints are present
if len(breakpoints) > 0 {
debugInfoVolumeMount := corev1.VolumeMount{
Name: debugInfoVolumeName,
MountPath: filepath.Join(debugInfoDir, fmt.Sprintf("%d", i)),
}
steps[i].VolumeMounts = append(steps[i].VolumeMounts, debugScriptsVolumeMount, debugInfoVolumeMount)
for i, s := range sidecars {
c := s.ToK8sContainer()
if s.Script != "" {
placeScriptInContainer(s.Script, getScriptFile(scriptsDir, fmt.Sprintf("%s-%d", namePrefix, i)), c, initContainer)
}
containers = append(containers, *c)
}
return containers
}

if s.Script == "" {
// Nothing to convert.
containers = append(containers, *steps[i].ToK8sContainer())
continue
// convertListOfSteps iterates through the list of steps, generates the script file name and heredoc termination string,
// adds an entry to the init container args, sets up the step container to run the script, and sets the volume mounts.
func convertListOfSteps(steps []v1beta1.Step, initContainer *corev1.Container, breakpoints []string, namePrefix string) []corev1.Container {
containers := []corev1.Container{}
for i, s := range steps {
c := steps[i].ToK8sContainer()
if s.Script != "" {
placeScriptInContainer(s.Script, getScriptFile(scriptsDir, fmt.Sprintf("%s-%d", namePrefix, i)), c, initContainer)
}
containers = append(containers, *c)
}
if len(breakpoints) > 0 {
placeDebugScriptInContainers(containers, initContainer)
}
return containers
}

// Check for a shebang, and add a default if it's not set.
// The shebang must be the first non-empty line.
cleaned := strings.TrimSpace(s.Script)
hasShebang := strings.HasPrefix(cleaned, "#!")
requiresWindows := strings.HasPrefix(cleaned, "#!win")
func getScriptFile(scriptsDir, scriptName string) string {
return filepath.Join(scriptsDir, names.SimpleNameGenerator.RestrictLengthWithRandomSuffix(scriptName))
}

script := s.Script
if !hasShebang {
script = defaultScriptPreamble + s.Script
}
// placeScriptInContainer given a piece of script to be executed, placeScriptInContainer firstly modifies initContainer
// so that it capsules the target script into scriptFile, then it modifies the container so that it can execute the scriptFile
// in runtime.
func placeScriptInContainer(script, scriptFile string, c *corev1.Container, initContainer *corev1.Container) {
if script == "" {
return
}
cleaned := strings.TrimSpace(script)
hasShebang := strings.HasPrefix(cleaned, "#!")
requiresWindows := strings.HasPrefix(cleaned, "#!win")

// At least one step uses a script, so we should return a
// non-nil init container.
*placeScripts = true
if !hasShebang {
script = defaultScriptPreamble + script
}

// Append to the place-scripts script to place the
// script file in a known location in the scripts volume.
scriptFile := filepath.Join(scriptsDir, names.SimpleNameGenerator.RestrictLengthWithRandomSuffix(fmt.Sprintf("%s-%d", namePrefix, i)))
if requiresWindows {
command, args, script, scriptFile := extractWindowsScriptComponents(script, scriptFile)
initContainer.Args[1] += fmt.Sprintf(`@"
// Append to the place-scripts script to place the
// script file in a known location in the scripts volume.
if requiresWindows {
command, args, script, scriptFile := extractWindowsScriptComponents(script, scriptFile)
initContainer.Args[1] += fmt.Sprintf(`@"
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%s
"@ | Out-File -FilePath %s
`, script, scriptFile)

steps[i].Command = command
// Append existing args field to end of derived args
args = append(args, steps[i].Args...)
steps[i].Args = args
} else {
// Only encode the script for linux scripts
// The decode-script subcommand of the entrypoint does not work under windows
script = encodeScript(script)
heredoc := "_EOF_" // underscores because base64 doesnt include them in its alphabet
initContainer.Args[1] += fmt.Sprintf(`scriptfile="%s"
c.Command = command
// Append existing args field to end of derived args
args = append(args, c.Args...)
c.Args = args
} else {
// Only encode the script for linux scripts
// The decode-script subcommand of the entrypoint does not work under windows
script = encodeScript(script)
heredoc := "_EOF_" // underscores because base64 doesn't include them in its alphabet
initContainer.Args[1] += fmt.Sprintf(`scriptfile="%s"
touch ${scriptfile} && chmod +x ${scriptfile}
cat > ${scriptfile} << '%s'
%s
%s
/tekton/bin/entrypoint decode-script "${scriptfile}"
`, scriptFile, heredoc, script, heredoc)

// Set the command to execute the correct script in the mounted
// volume.
// A previous merge with stepTemplate may have populated
// Command and Args, even though this is not normally valid, so
// we'll clear out the Args and overwrite Command.
steps[i].Command = []string{scriptFile}
}
steps[i].VolumeMounts = append(steps[i].VolumeMounts, scriptsVolumeMount)

containers = append(containers, *steps[i].ToK8sContainer())
// Set the command to execute the correct script in the mounted volume.
// A previous merge with stepTemplate may have populated
// Command and Args, even though this is not normally valid, so
// we'll clear out the Args and overwrite Command.
c.Command = []string{scriptFile}
}
c.VolumeMounts = append(c.VolumeMounts, scriptsVolumeMount)
}

// Place debug scripts if breakpoints are enabled
if len(breakpoints) > 0 {
// If breakpoint is not nil then should add the init container
// to write debug script files
*placeScripts = true
// encodeScript encodes a script field into a format that avoids kubernetes' built-in processing of container args,
// which can mangle dollar signs and unexpectedly replace variable references in the user's script.
func encodeScript(script string) string {
return base64.StdEncoding.EncodeToString([]byte(script))
}

type script struct {
name string
content string
}
debugScripts := []script{{
name: "continue",
content: defaultScriptPreamble + fmt.Sprintf(debugContinueScriptTemplate, len(steps), debugInfoDir, RunDir),
}, {
name: "fail-continue",
content: defaultScriptPreamble + fmt.Sprintf(debugFailScriptTemplate, len(steps), debugInfoDir, RunDir),
}}

// Add debug or breakpoint related scripts to /tekton/debug/scripts
// Iterate through the debugScripts and add routine for each of them in the initContainer for their creation
for _, debugScript := range debugScripts {
tmpFile := filepath.Join(debugScriptsDir, fmt.Sprintf("%s-%s", "debug", debugScript.name))
heredoc := names.SimpleNameGenerator.RestrictLengthWithRandomSuffix(fmt.Sprintf("%s-%s-heredoc-randomly-generated", "debug", debugScript.name))

initContainer.Args[1] += fmt.Sprintf(initScriptDirective, tmpFile, heredoc, debugScript.content, heredoc)
// placeDebugScriptInContainers inserts debug scripts into containers. It capsules those scripts to files in initContainer,
// then executes those scripts in target containers.
func placeDebugScriptInContainers(containers []corev1.Container, initContainer *corev1.Container) {
for i := 0; i < len(containers); i++ {
debugInfoVolumeMount := corev1.VolumeMount{
Name: debugInfoVolumeName,
MountPath: filepath.Join(debugInfoDir, fmt.Sprintf("%d", i)),
}
(&containers[i]).VolumeMounts = append((&containers[i]).VolumeMounts, debugScriptsVolumeMount, debugInfoVolumeMount)
}

return containers
type script struct {
name string
content string
}
debugScripts := []script{{
name: "continue",
content: defaultScriptPreamble + fmt.Sprintf(debugContinueScriptTemplate, len(containers), debugInfoDir, RunDir),
}, {
name: "fail-continue",
content: defaultScriptPreamble + fmt.Sprintf(debugFailScriptTemplate, len(containers), debugInfoDir, RunDir),
}}

// Add debug or breakpoint related scripts to /tekton/debug/scripts
// Iterate through the debugScripts and add routine for each of them in the initContainer for their creation
for _, debugScript := range debugScripts {
tmpFile := filepath.Join(debugScriptsDir, fmt.Sprintf("%s-%s", "debug", debugScript.name))
heredoc := names.SimpleNameGenerator.RestrictLengthWithRandomSuffix(fmt.Sprintf("%s-%s-heredoc-randomly-generated", "debug", debugScript.name))

initContainer.Args[1] += fmt.Sprintf(initScriptDirective, tmpFile, heredoc, debugScript.content, heredoc)
}
}

// encodeScript encodes a script field into a format that avoids kubernetes' built-in processing of container args,
// which can mangle dollar signs and unexpectedly replace variable references in the user's script.
func encodeScript(script string) string {
return base64.StdEncoding.EncodeToString([]byte(script))
// hasScripts determines if we need to generate scripts in InitContainer given steps, sidecars and breakpoints.
func hasScripts(steps []v1beta1.Step, sidecars []v1beta1.Sidecar, breakpoints []string) bool {
for _, s := range steps {
if s.Script != "" {
return true
}
}
for _, s := range sidecars {
if s.Script != "" {
return true
}
}
return len(breakpoints) > 0
}

func checkWindowsRequirement(steps []v1beta1.Step, sidecars []v1beta1.Sidecar) bool {
Expand Down
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