feat: Support events.preStop

Fix devfile#1139

Signed-off-by: Andrew Obuchowicz <aobuchow@redhat.com>

pkg/library/container/container.go

@@ -80,6 +80,10 @@ func GetKubeContainersFromDevfile(workspace *dw.DevWorkspaceTemplateSpec, securi
 		return nil, err
 	}
 
+	if err := lifecycle.AddPreStopLifecycleHooks(workspace, podAdditions.Containers); err != nil {
+		return nil, err
+	}
+
 	for _, initComponent := range initComponents {
 		k8sContainer, err := convertContainerToK8s(initComponent, securityContext, pullPolicy, defaultResources)
 		if err != nil {

pkg/library/lifecycle/prestop.go

@@ -0,0 +1,107 @@
+// Copyright (c) 2019-2023 Red Hat, Inc.
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package lifecycle
+
+import (
+	"fmt"
+	"strings"
+
+	dw "github.com/devfile/api/v2/pkg/apis/workspaces/v1alpha2"
+	corev1 "k8s.io/api/core/v1"
+)
+
+const redirectPreStopOutputFmt = `{
+%s
+} 1>/proc/1/fd/1 2>/proc/1/fd/2
+`
+
+func AddPreStopLifecycleHooks(wksp *dw.DevWorkspaceTemplateSpec, containers []corev1.Container) error {
+	if wksp.Events == nil || len(wksp.Events.PreStop) == 0 {
+		return nil
+	}
+
+	componentToCommands := map[string][]dw.Command{}
+	for _, commandName := range wksp.Events.PreStop {
+		command, err := getCommandByKey(commandName, wksp.Commands)
+		if err != nil {
+			return fmt.Errorf("could not resolve command for preStop event '%s': %w", commandName, err)
+		}
+		cmdType, err := getCommandType(*command)
+		if err != nil {
+			return fmt.Errorf("could not determine command type for '%s': %w", command.Key(), err)
+		}
+		if cmdType != dw.ExecCommandType {
+			return fmt.Errorf("can not use %s-type command in preStop lifecycle event", cmdType)
+		}
+		componentToCommands[command.Exec.Component] = append(componentToCommands[command.Exec.Component], *command)
+	}
+
+	for componentName, commands := range componentToCommands {
+		cmdContainer, err := getContainerWithName(componentName, containers)
+		if err != nil {
+			return fmt.Errorf("failed to process preStop event '%s': %w", commands[0].Id, err)
+		}
+
+		preStopHandler, err := processCommandsForPreStop(commands)
+		if err != nil {
+			return fmt.Errorf("failed to process preStop event '%s': %w", commands[0].Id, err)
+		}
+
+		if cmdContainer.Lifecycle == nil {
+			cmdContainer.Lifecycle = &corev1.Lifecycle{}
+		}
+		cmdContainer.Lifecycle.PreStop = preStopHandler
+	}
+
+	return nil
+}
+
+// processCommandsForPreStop builds a lifecycle handler that runs the provided command(s)
+// The command has the format
+//
+//	exec:
+//		command:
+//		  - "/bin/sh"
+//		  - "-c"
+//		  - |
+//	        {
+//		    cd <workingDir>
+//		    <commandline>
+//	        } 1>/proc/1/fd/1 2>/proc/1/fd/2
+func processCommandsForPreStop(commands []dw.Command) (*corev1.LifecycleHandler, error) {
+	var dwCommands []string
+	for _, command := range commands {
+		execCmd := command.Exec
+		if len(execCmd.Env) > 0 {
+			return nil, fmt.Errorf("env vars in preStop command %s are unsupported", command.Id)
+		}
+		if execCmd.WorkingDir != "" {
+			dwCommands = append(dwCommands, fmt.Sprintf("cd %s", execCmd.WorkingDir))
+		}
+		dwCommands = append(dwCommands, execCmd.CommandLine)
+	}
+
+	joinedCommands := strings.Join(dwCommands, "\n")
+
+	handler := &corev1.LifecycleHandler{
+		Exec: &corev1.ExecAction{
+			Command: []string{
+				"/bin/sh",
+				"-c",
+				fmt.Sprintf(redirectPreStopOutputFmt, joinedCommands),
+			},
+		},
+	}
+	return handler, nil
+}