Switch to running without Supervisord as PID 1 in containers

To do this, the idea is to start the container component:
1- using the command/args defined in the Devfile
2- using whatever was defined in the container image
   if there is no command/args defined in the Devfile

Then, once the container is started, we would execute the Devfile
commands directly in the container component, just like a simple
'kubectl exec' command would do.
Since this is a long-running command (and potentially never ending),
we would need to run it in the background, i.e. in a side goroutine.

Point 2) above requires implementing a temporary hack (as discussed in [1]),
without us having to wait for [2] to be merged on the Devfile side.
This temporary hack overrides the container entrypoint with "tail -f /dev/null"
if the component defines no command or args (in which case we should have
used whatever is defined in the image, per the specification).

[1] redhat-developer#5768 (comment)
[2] devfile/registry#102

Author: rm3l

docs/website/versioned_docs/version-3.0.0/command-reference/dev.md

@@ -208,6 +208,9 @@ components:
     mountSources: true
 ```
 
+Note that `odo` will set the container entrypoint to `tail -f /dev/null` if no `command` or `args` fields are explicitly defined for this component in the Devfile.
+This is a temporary workaround that allows `odo` to start non-terminating containers in which the Devfile commands will get executed.
+
 ### Full Example
 
 ```yaml

pkg/devfile/adapters/common/executor.go

@@ -1,11 +1,6 @@
 package common
 
-import (
-	devfilev1 "github.com/devfile/api/v2/pkg/apis/workspaces/v1alpha2"
-)
-
 // ComponentAdapter defines the functions that platform-specific adapters must implement
 type ComponentAdapter interface {
 	Push(parameters PushParameters) error
-	CheckSupervisordCommandStatus(command devfilev1.Command) error
 }

pkg/devfile/adapters/common/generic.go

@@ -1,162 +1,23 @@
 package common
 
 import (
-	"os"
 	"path/filepath"
 	"strings"
 
-	"k8s.io/klog"
-
 	devfilev1 "github.com/devfile/api/v2/pkg/apis/workspaces/v1alpha2"
-	parsercommon "github.com/devfile/library/pkg/devfile/parser/data/v2/common"
 )
 
-// PredefinedDevfileCommands encapsulates constants for predefined devfile commands
-type PredefinedDevfileCommands string
-
 const (
-
-	// DefaultDevfileRunCommand is a predefined devfile command for run
-	DefaultDevfileRunCommand PredefinedDevfileCommands = "devrun"
-
-	// DefaultDevfileDebugCommand is a predefined devfile command for debug
-	DefaultDevfileDebugCommand PredefinedDevfileCommands = "debugrun"
-
-	// SupervisordInitContainerName The init container name for supervisord
-	SupervisordInitContainerName = "copy-supervisord"
-
-	// Default Image that will be used containing the supervisord binary and assembly scripts
-	// use GetBootstrapperImage() function instead of this variable
-	defaultBootstrapperImage = "registry.access.redhat.com/ocp-tools-4/odo-init-container-rhel8:1.1.11"
-
-	// SupervisordVolumeName Create a custom name and (hope) that users don't use the *exact* same name in their deployment (occlient.go)
-	SupervisordVolumeName = "odo-supervisord-shared-data"
-
-	// SupervisordMountPath The supervisord Mount Path for the container mounting the supervisord volume
-	SupervisordMountPath = "/opt/odo/"
-
-	// SupervisordBinaryPath The supervisord binary path inside the container volume mount
-	SupervisordBinaryPath = "/opt/odo/bin/supervisord"
-
-	// SupervisordConfFile The supervisord configuration file inside the container volume mount
-	SupervisordConfFile = "/opt/odo/conf/devfile-supervisor.conf"
-
-	// OdoInitImageContents The path to the odo init image contents
-	OdoInitImageContents = "/opt/odo-init/."
-
-	// ENV variable to overwrite image used to bootstrap SupervisorD in S2I and Devfile builder Image
-	bootstrapperImageEnvName = "ODO_BOOTSTRAPPER_IMAGE"
-
 	// EnvProjectsRoot is the env defined for project mount in a component container when component's mountSources=true
 	EnvProjectsRoot = "PROJECTS_ROOT"
 
-	// EnvOdoCommandRunWorkingDir is the env defined in the runtime component container which holds the work dir for the run command
-	EnvOdoCommandRunWorkingDir = "ODO_COMMAND_RUN_WORKING_DIR"
-
-	// EnvOdoCommandRun is the env defined in the runtime component container which holds the run command to be executed
-	EnvOdoCommandRun = "ODO_COMMAND_RUN"
-
-	// EnvOdoCommandDebugWorkingDir is the env defined in the runtime component container which holds the work dir for the debug command
-	EnvOdoCommandDebugWorkingDir = "ODO_COMMAND_DEBUG_WORKING_DIR"
-
-	// EnvOdoCommandDebug is the env defined in the runtime component container which holds the debug command to be executed
-	EnvOdoCommandDebug = "ODO_COMMAND_DEBUG"
-
 	// EnvDebugPort is the env defined in the runtime component container which holds the debug port for remote debugging
 	EnvDebugPort = "DEBUG_PORT"
 
 	// ShellExecutable is the shell executable
 	ShellExecutable = "/bin/sh"
-
-	// SupervisordCtlSubCommand is the supervisord sub command ctl
-	SupervisordCtlSubCommand = "ctl"
 )
 
-// GetBootstrapperImage returns the odo-init bootstrapper image
-func GetBootstrapperImage() string {
-	if env, ok := os.LookupEnv(bootstrapperImageEnvName); ok {
-		return env
-	}
-	return defaultBootstrapperImage
-}
-
-// getCommandsByGroup gets commands by the group kind
-func getCommandsByGroup(commands []devfilev1.Command, groupType devfilev1.CommandGroupKind) []devfilev1.Command {
-	var filteredCommands []devfilev1.Command
-	for _, command := range commands {
-		commandGroup := parsercommon.GetGroup(command)
-		if commandGroup != nil && commandGroup.Kind == groupType {
-			filteredCommands = append(filteredCommands, command)
-		}
-	}
-
-	return filteredCommands
-}
-
-// IsRestartRequired checks if restart required for run command
-func IsRestartRequired(hotReload bool, runModeChanged bool) bool {
-	if runModeChanged || !hotReload {
-		return true
-	}
-
-	return false
-}
-
-// IsEnvPresent checks if the env variable is present in an array of env variables
-func IsEnvPresent(envVars []devfilev1.EnvVar, envVarName string) bool {
-	for _, envVar := range envVars {
-		if envVar.Name == envVarName {
-			return true
-		}
-	}
-
-	return false
-}
-
-// IsPortPresent checks if the port is present in the endpoints array
-func IsPortPresent(endpoints []devfilev1.Endpoint, port int) bool {
-	for _, endpoint := range endpoints {
-		if endpoint.TargetPort == port {
-			return true
-		}
-	}
-
-	return false
-}
-
-// GetComponentEnvVar returns true if a list of env vars contains the specified env var
-// If the env exists, it returns the value of it
-func GetComponentEnvVar(env string, envs []devfilev1.EnvVar) string {
-	for _, envVar := range envs {
-		if envVar.Name == env {
-			return envVar.Value
-		}
-	}
-	return ""
-}
-
-// GetCommandsFromEvent returns the list of commands from the event name.
-// If the event is a composite command, it returns the sub-commands from the tree
-func GetCommandsFromEvent(commandsMap map[string]devfilev1.Command, eventName string) []string {
-	var commands []string
-
-	if command, ok := commandsMap[eventName]; ok {
-		if command.Composite != nil {
-			klog.V(4).Infof("%s is a composite command", command.Id)
-			for _, compositeSubCmd := range command.Composite.Commands {
-				klog.V(4).Infof("checking if sub-command %s is either an exec or a composite command ", compositeSubCmd)
-				subCommands := GetCommandsFromEvent(commandsMap, strings.ToLower(compositeSubCmd))
-				commands = append(commands, subCommands...)
-			}
-		} else {
-			klog.V(4).Infof("%s is an exec command", command.Id)
-			commands = append(commands, command.Id)
-		}
-	}
-
-	return commands
-}
-
 // GetCommandsMap returns a map of the command Id to the command
 func GetCommandsMap(commands []devfilev1.Command) map[string]devfilev1.Command {
 	commandMap := make(map[string]devfilev1.Command, len(commands))