feat: shutdown in reverse dependency order

fixtures-code/process-compose-shutdown-inorder.yaml

@@ -0,0 +1,29 @@
+version: "0.5"
+
+log_level: debug
+log_length: 1000
+
+processes:
+  procA:
+    command: |
+      trap 'echo "A: exit"' SIGTERM
+      echo "A: starting"
+      sleep 3
+
+  procB:
+    command: |
+      trap 'echo "B: exit"' SIGTERM
+      echo "B: starting"
+      sleep 3
+    depends_on:
+      procA:
+        condition: process_started
+
+  procC:
+    command: |
+      trap 'echo "C: exit"' SIGTERM
+      echo "C: starting"
+      sleep 3
+    depends_on:
+      procB:
+        condition: process_started

src/app/project_opts.go

@@ -3,12 +3,13 @@ package app
 import "github.com/f1bonacc1/process-compose/src/types"
 
 type ProjectOpts struct {
-	project         *types.Project
-	processesToRun  []string
-	noDeps          bool
-	mainProcess     string
-	mainProcessArgs []string
-	isTuiOn         bool
+	project           *types.Project
+	processesToRun    []string
+	noDeps            bool
+	mainProcess       string
+	mainProcessArgs   []string
+	isTuiOn           bool
+	isOrderedShutDown bool
 }
 
 func (p *ProjectOpts) WithProject(project *types.Project) *ProjectOpts {
@@ -39,3 +40,8 @@ func (p *ProjectOpts) WithIsTuiOn(isTuiOn bool) *ProjectOpts {
 	p.isTuiOn = isTuiOn
 	return p
 }
+
+func (p *ProjectOpts) WithOrderedShutDown(isOrderedShutDown bool) *ProjectOpts {
+	p.isOrderedShutDown = isOrderedShutDown
+	return p
+}

src/app/project_runner.go

@@ -8,28 +8,30 @@ import (
 	"os"
 	"os/user"
 	"runtime"
+	"slices"
 	"sync"
 	"time"
 
 	"github.com/rs/zerolog/log"
 )
 
 type ProjectRunner struct {
-	procConfMutex    sync.Mutex
-	project          *types.Project
-	logsMutex        sync.Mutex
-	processLogs      map[string]*pclog.ProcessLogBuffer
-	statesMutex      sync.Mutex
-	processStates    map[string]*types.ProcessState
-	runProcMutex     sync.Mutex
-	runningProcesses map[string]*Process
-	logger           pclog.PcLogger
-	waitGroup        sync.WaitGroup
-	exitCode         int
-	projectState     *types.ProjectState
-	mainProcess      string
-	mainProcessArgs  []string
-	isTuiOn          bool
+	procConfMutex     sync.Mutex
+	project           *types.Project
+	logsMutex         sync.Mutex
+	processLogs       map[string]*pclog.ProcessLogBuffer
+	statesMutex       sync.Mutex
+	processStates     map[string]*types.ProcessState
+	runProcMutex      sync.Mutex
+	runningProcesses  map[string]*Process
+	logger            pclog.PcLogger
+	waitGroup         sync.WaitGroup
+	exitCode          int
+	projectState      *types.ProjectState
+	mainProcess       string
+	mainProcessArgs   []string
+	isTuiOn           bool
+	isOrderedShutDown bool
 }
 
 func (p *ProjectRunner) GetLexicographicProcessNames() ([]string, error) {
@@ -322,27 +324,111 @@ func (p *ProjectRunner) GetProcessPorts(name string) (*types.ProcessPorts, error
 	return ports, nil
 }
 
+func (p *ProjectRunner) runningProcessesReverseDependencies() map[string]map[string]*Process {
+	reverseDependencies := make(map[string]map[string]*Process)
+
+	// `p.runProcMutex` lock is assumed to have been acquired when calling
+	// this function. It is currently called by `ShutDownProject()`.
+	for _, process := range p.runningProcesses {
+		for k := range process.procConf.DependsOn {
+			if runningProc, ok := p.runningProcesses[k]; ok {
+				if _, ok := reverseDependencies[runningProc.getName()]; !ok {
+					dep := make(map[string]*Process)
+					dep[process.getName()] = process
+					reverseDependencies[runningProc.getName()] = dep
+				}
+			} else {
+				continue
+			}
+		}
+	}
+
+	return reverseDependencies
+}
+
+func (p *ProjectRunner) shutDownInOrder(wg *sync.WaitGroup, shutdownOrder []*Process) {
+	reverseDependencies := p.runningProcessesReverseDependencies()
+	for _, process := range shutdownOrder {
+		wg.Add(1)
+		go func(proc *Process) {
+			defer wg.Done()
+			waitForDepsWg := sync.WaitGroup{}
+			if revDeps, ok := reverseDependencies[proc.getName()]; ok {
+				for _, runningProc := range revDeps {
+					waitForDepsWg.Add(1)
+					go func(pr *Process) {
+						pr.waitForCompletion()
+						waitForDepsWg.Done()
+					}(runningProc)
+				}
+			}
+			waitForDepsWg.Wait()
+			log.Debug().Msgf("[%s]: waited for all dependencies to shut down", proc.getName())
+
+			err := proc.shutDown()
+			if err != nil {
+				log.Err(err).Msgf("failed to shutdown %s", proc.getName())
+				return
+			}
+			proc.waitForCompletion()
+		}(process)
+	}
+}
+
+func (p *ProjectRunner) shutDownAndWait(shutdownOrder []*Process) {
+	wg := sync.WaitGroup{}
+	if p.isOrderedShutDown {
+		p.shutDownInOrder(&wg, shutdownOrder)
+	} else {
+		for _, proc := range shutdownOrder {
+			err := proc.shutDown()
+			if err != nil {
+				log.Err(err).Msgf("failed to shutdown %s", proc.getName())
+				continue
+			}
+			wg.Add(1)
+			go func(pr *Process) {
+				pr.waitForCompletion()
+				wg.Done()
+			}(proc)
+		}
+	}
+
+	wg.Wait()
+}
+
 func (p *ProjectRunner) ShutDownProject() error {
 	p.runProcMutex.Lock()
 	defer p.runProcMutex.Unlock()
-	runProc := p.runningProcesses
-	for _, proc := range runProc {
-		proc.prepareForShutDown()
-	}
-	wg := sync.WaitGroup{}
-	for _, proc := range runProc {
-		err := proc.shutDown()
+
+	shutdownOrder := []*Process{}
+	if p.isOrderedShutDown {
+		err := p.project.WithProcesses([]string{}, func(process types.ProcessConfig) error {
+			if runningProc, ok := p.runningProcesses[process.ReplicaName]; ok {
+				shutdownOrder = append(shutdownOrder, runningProc)
+			}
+			return nil
+		})
 		if err != nil {
-			log.Err(err).Msgf("failed to shutdown %s", proc.getName())
-			continue
+			log.Error().Msgf("Failed to build project run order: %s", err.Error())
+		}
+		slices.Reverse(shutdownOrder)
+	} else {
+		for _, proc := range p.runningProcesses {
+			shutdownOrder = append(shutdownOrder, proc)
 		}
-		wg.Add(1)
-		go func(pr *Process) {
-			pr.waitForCompletion()
-			wg.Done()
-		}(proc)
 	}
-	wg.Wait()
+
+	var nameOrder []string
+	for _, v := range shutdownOrder {
+		nameOrder = append(nameOrder, v.getName())
+	}
+	log.Debug().Msgf("Shutting down %d processes. Order: %q", len(shutdownOrder), nameOrder)
+	for _, proc := range shutdownOrder {
+		proc.prepareForShutDown()
+	}
+
+	p.shutDownAndWait(shutdownOrder)
 	return nil
 }
 
@@ -644,10 +730,11 @@ func NewProjectRunner(opts *ProjectOpts) (*ProjectRunner, error) {
 		username = current.Username
 	}
 	runner := &ProjectRunner{
-		project:         opts.project,
-		mainProcess:     opts.mainProcess,
-		mainProcessArgs: opts.mainProcessArgs,
-		isTuiOn:         opts.isTuiOn,
+		project:           opts.project,
+		mainProcess:       opts.mainProcess,
+		mainProcessArgs:   opts.mainProcessArgs,
+		isTuiOn:           opts.isTuiOn,
+		isOrderedShutDown: opts.isOrderedShutDown,
 		projectState: &types.ProjectState{
 			FileNames: opts.project.FileNames,
 			StartTime: time.Now(),

src/app/system_test.go

@@ -1,10 +1,14 @@
 package app
 
 import (
+	"bufio"
 	"github.com/f1bonacc1/process-compose/src/loader"
+	"github.com/f1bonacc1/process-compose/src/types"
 	"os"
 	"path/filepath"
 	"reflect"
+	"slices"
+	"strings"
 	"testing"
 	"time"
 )
@@ -406,3 +410,94 @@ func TestSystem_TestProcListToRun(t *testing.T) {
 		}
 	})
 }
+
+func TestSystem_TestProcListShutsDownInOrder(t *testing.T) {
+	fixture1 := filepath.Join("..", "..", "fixtures-code", "process-compose-shutdown-inorder.yaml")
+	t.Run("Single Proc with deps", func(t *testing.T) {
+
+		project, err := loader.Load(&loader.LoaderOptions{
+			FileNames: []string{fixture1},
+		})
+		if err != nil {
+			t.Errorf(err.Error())
+			return
+		}
+		numProc := len(project.Processes)
+		runner, err := NewProjectRunner(&ProjectOpts{
+			project:           project,
+			processesToRun:    []string{},
+			mainProcessArgs:   []string{},
+			isOrderedShutDown: true,
+		})
+		if err != nil {
+			t.Errorf(err.Error())
+			return
+		}
+		if len(runner.project.Processes) != numProc {
+			t.Errorf("should have %d processes", numProc)
+		}
+		for name, proc := range runner.project.Processes {
+			if proc.Disabled {
+				t.Errorf("process %s is disabled", name)
+			}
+		}
+		file, err := os.CreateTemp("/tmp", "pc_log.*.log")
+		defer os.Remove(file.Name())
+		project.LogLocation = file.Name()
+		project.LoggerConfig = &types.LoggerConfig{
+			FieldsOrder:     []string{"message"},
+			DisableJSON:     true,
+			TimestampFormat: "",
+			NoMetadata:      true,
+			FlushEachLine:   true,
+			NoColor:         true,
+		}
+		go runner.Run()
+		time.Sleep(10 * time.Millisecond)
+		states, err := runner.GetProcessesState()
+		if err != nil {
+			t.Errorf(err.Error())
+			return
+		}
+		want := 3
+		if len(states.States) != want {
+			t.Errorf("len(states.States) = %d, want %d", len(states.States), want)
+		}
+
+		time.Sleep(10 * time.Millisecond)
+		err = runner.ShutDownProject()
+		if err != nil {
+			t.Errorf(err.Error())
+			return
+		}
+		states, err = runner.GetProcessesState()
+		if err != nil {
+			t.Errorf(err.Error())
+			return
+		}
+		runningProcesses := 0
+		for _, processState := range states.States {
+			if processState.IsRunning {
+				runningProcesses++
+			}
+		}
+		want = 0
+		if runningProcesses != want {
+			t.Errorf("runningProcesses = %d, want %d", runningProcesses, want)
+		}
+		//read file and validate the shutdown order
+		scanner := bufio.NewScanner(file)
+		order := make([]string, 0)
+		for scanner.Scan() {
+			line := scanner.Text()
+			if strings.Contains(line, "exit") {
+				order = append(order, line)
+			}
+		}
+		wantOrder := []string{"C: exit", "B: exit", "A: exit"}
+		if !slices.Equal(order, wantOrder) {
+			t.Errorf("content = %v, want %v", order, wantOrder)
+			return
+		}
+	})
+}

src/cmd/project_runner.go

@@ -29,6 +29,7 @@ func getProjectRunner(process []string, noDeps bool, mainProcess string, mainPro
 			WithMainProcessArgs(mainProcessArgs).
 			WithProject(project).
 			WithProcessesToRun(process).
+			WithOrderedShutDown(*pcFlags.IsOrderedShutDown).
 			WithNoDeps(noDeps),
 	)
 	if err != nil {

src/cmd/root.go

@@ -63,6 +63,7 @@ func init() {
 	rootCmd.Flags().BoolVarP(pcFlags.Headless, "tui", "t", *pcFlags.Headless, "enable TUI (-t=false) (env: "+config.EnvVarNameTui+")")
 	rootCmd.PersistentFlags().BoolVar(pcFlags.KeepTuiOn, "keep-tui", *pcFlags.KeepTuiOn, "keep TUI running even after all processes exit")
 	rootCmd.PersistentFlags().BoolVar(pcFlags.NoServer, "no-server", *pcFlags.NoServer, "disable HTTP server (env: "+config.EnvVarNameNoServer+")")
+	rootCmd.PersistentFlags().BoolVar(pcFlags.IsOrderedShutDown, "ordered-shutdown", *pcFlags.IsOrderedShutDown, "shut down processes in reverse dependency order")
 	rootCmd.Flags().BoolVarP(pcFlags.HideDisabled, "hide-disabled", "d", *pcFlags.HideDisabled, "hide disabled processes")
 	rootCmd.Flags().IntVarP(pcFlags.RefreshRate, "ref-rate", "r", *pcFlags.RefreshRate, "TUI refresh rate in seconds")
 	rootCmd.PersistentFlags().IntVarP(pcFlags.PortNum, "port", "p", *pcFlags.PortNum, "port number (env: "+config.EnvVarNamePort+")")