backup: Move taking snapshot to separate function

This commit moves taking a snapshot of a running instance to a separate
function.

TODO.md

@@ -27,6 +27,7 @@ Work in progress.
 - Migrate the individual commands below
 - restructure resource files
 - Documentation
+- single malt
 
 ## Migrating Individual Commands
 - [ ] backup_all.sh

cmd/backup.go

@@ -2,13 +2,11 @@ package cmd
 
 import (
 	"fmt"
-	"io/fs"
 	"os"
 	"path/filepath"
 
 	wisski_distillery "github.com/FAU-CDI/wisski-distillery"
 	"github.com/FAU-CDI/wisski-distillery/env"
-	"github.com/FAU-CDI/wisski-distillery/internal/fsx"
 	"github.com/FAU-CDI/wisski-distillery/internal/logging"
 	"github.com/FAU-CDI/wisski-distillery/internal/targz"
 	"github.com/tkw1536/goprogram/exit"
@@ -63,11 +61,28 @@ func (bi backupInstance) Run(context wisski_distillery.Context) error {
 		os.RemoveAll(path) // TODO: Turn this on again
 	}()
 
-	// make the snapshot!
-	// TODO: Ignore errors here, and write them into the snapshot instance
-	if err := bi.makeSnapshot(context, path, instance); err != nil {
-		return errBackupFailed.WithMessageF(err)
+	// make a snapshot and write out the report also!
+	logging.LogOperation(func() error {
+		sreport := instance.Snapshot(context.IOStream, bi.Keepalive, path)
+
+		logging.LogOperation(func() error {
+			reportPath := filepath.Join(path, "report.txt")
+			context.Println(reportPath)
+
+			// create the report file!
+			report, err := os.Create(reportPath)
+			if err != nil {
+				return err
 			}
+			defer report.Close()
+
+			// print the report into it!
+			_, err = fmt.Fprintf(report, "%#v\n", sreport)
+			return err
+		}, context.IOStream, "Writing snapshot report")
+
+		return nil
+	}, context.IOStream, "Creating snapshot")
 
 	// copy everything into the final file!
 	finalPath := bi.Positionals.Outfile
@@ -89,95 +104,3 @@ func (bi backupInstance) Run(context wisski_distillery.Context) error {
 
 	return nil
 }
-
-// makeSnapshot makes a snapshot of the directory into the given directory!
-//
-// TODO: Return a SnapshotReport object, and only check what was actually copied
-func (bi backupInstance) makeSnapshot(context wisski_distillery.Context, path string, instance env.Instance) error {
-	dis := context.Environment
-	stack := instance.Stack()
-
-	if !bi.Keepalive {
-		logging.LogMessage(context.IOStream, "Stopping instance")
-		if err := stack.Down(context.IOStream); err != nil {
-			return err
-		}
-		defer func() {
-			logging.LogMessage(context.IOStream, "Starting instance")
-			stack.Up(context.IOStream)
-		}()
-	}
-
-	// backup up bookkeeping info!
-	if err := logging.LogOperation(func() error {
-		bkPath := filepath.Join(path, "bookkeeping.txt")
-		context.IOStream.Println(bkPath)
-
-		// create the backup file!
-		info, err := os.Create(bkPath)
-		if err != nil {
-			return err
-		}
-		defer info.Close()
-
-		// print whatever is in the bookkeeping instance
-		_, err = fmt.Fprintf(info, "%#v\n", instance.Instance)
-		return err
-	}, context.IOStream, "Backing up Bookkeping Information"); err != nil {
-		return errBackupFailed.Wrap(err)
-	}
-
-	// backup the filesystem!
-	if err := logging.LogOperation(func() error {
-		// create a backup directory
-		fsPath := filepath.Join(path, filepath.Base(instance.FilesystemBase))
-		if err := os.Mkdir(fsPath, fs.ModeDir); err != nil {
-			return err
-		}
-
-		return fsx.CopyDirectory(fsPath, instance.FilesystemBase, func(dst, src string) {
-			context.IOStream.Println(src)
-		})
-	}, context.IOStream, "Backing up filesystem"); err != nil {
-		return errBackupFailed.Wrap(err)
-	}
-
-	// backup the the triplestore!
-	if err := logging.LogOperation(func() error {
-		tsPath := filepath.Join(path, instance.GraphDBRepository+".nq")
-		context.IOStream.Println(tsPath)
-
-		// create the backup file!
-		nquads, err := os.Create(tsPath)
-		if err != nil {
-			return err
-		}
-		defer nquads.Close()
-
-		// TODO: Add a progress bar?
-		_, err = dis.Triplestore().Backup(nquads, instance.GraphDBRepository)
-		return err
-	}, context.IOStream, "Backing up Triplestore"); err != nil {
-		return errBackupFailed.Wrap(err)
-	}
-
-	// backup the the sql database!
-	if err := logging.LogOperation(func() error {
-		sqlPath := filepath.Join(path, instance.SqlDatabase+".sql")
-		context.IOStream.Println(sqlPath)
-
-		// create the backup file!
-		sql, err := os.Create(sqlPath)
-		if err != nil {
-			return err
-		}
-		defer sql.Close()
-
-		// TODO: Add a progress bar?
-		return dis.SQL().Backup(context.IOStream, sql, instance.SqlDatabase)
-	}, context.IOStream, "Backing up Triplestore"); err != nil {
-		return errBackupFailed.Wrap(err)
-	}
-
-	return nil
-}

env/snapshot.go

@@ -0,0 +1,140 @@
+package env
+
+import (
+	"fmt"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"sync"
+
+	"github.com/FAU-CDI/wisski-distillery/internal/fsx"
+	"github.com/FAU-CDI/wisski-distillery/internal/logging"
+	"github.com/tkw1536/goprogram/stream"
+)
+
+type SnapshotReport struct {
+	Keepalive bool        // was the instance alive while running the snapshot?
+	Panic     interface{} // was there a panic?
+
+	// errors for the various components of the Snapshot
+	StopErr        error
+	StartErr       error
+	BookkeepingErr error
+	FilesystemErr  error
+	TriplestoreErr error
+	SQLErr         error
+}
+
+// Snapshot creates a new snapshot of this instance into dest
+func (instance Instance) Snapshot(io stream.IOStream, keepalive bool, dest string) (report SnapshotReport) {
+	// catch anything critical that happened during the snapshot
+	defer func() {
+		report.Panic = recover()
+	}()
+
+	stack := instance.Stack()
+
+	// stop the instance (unless it was explicitly asked to not do so!)
+	report.Keepalive = keepalive
+	if !keepalive {
+		logging.LogMessage(io, "Stopping instance")
+		report.StopErr = stack.Down(io)
+		defer func() {
+			logging.LogMessage(io, "Starting instance")
+			report.StartErr = stack.Up(io)
+		}()
+	}
+
+	// create a wait group, and message channel
+	wg := &sync.WaitGroup{}
+	messages := make(chan string, 4)
+
+	// write bookkeeping information
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+
+		bkPath := filepath.Join(dest, "bookkeeping.txt")
+		messages <- bkPath
+
+		info, err := os.Create(bkPath)
+		if err != nil {
+			report.BookkeepingErr = err
+			return
+		}
+		defer info.Close()
+
+		// print whatever is in the database
+		// TODO: This should be sql code, maybe gorm can do that?
+		_, report.BookkeepingErr = fmt.Fprintf(info, "%#v\n", instance.Instance)
+	}()
+
+	// backup the filesystem
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+
+		fsPath := filepath.Join(dest, filepath.Base(instance.FilesystemBase))
+		if err := os.Mkdir(fsPath, fs.ModeDir); err != nil {
+			report.FilesystemErr = err
+			return
+		}
+
+		// copy over whatever is in the base directory
+		report.FilesystemErr = fsx.CopyDirectory(fsPath, instance.FilesystemBase, func(dst, src string) {
+			messages <- dst
+		})
+	}()
+
+	// backup the graph db repository
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+
+		tsPath := filepath.Join(dest, instance.GraphDBRepository+".nq")
+		messages <- tsPath
+
+		nquads, err := os.Create(tsPath)
+		if err != nil {
+			report.TriplestoreErr = err
+		}
+		defer nquads.Close()
+
+		// directly store the result
+		_, report.TriplestoreErr = instance.dis.Triplestore().Backup(nquads, instance.GraphDBRepository)
+	}()
+
+	// backup the sql database
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+
+		sqlPath := filepath.Join(dest, instance.SqlDatabase+".sql")
+		messages <- sqlPath
+
+		sql, err := os.Create(sqlPath)
+		if err != nil {
+			report.SQLErr = err
+			return
+		}
+		defer sql.Close()
+
+		// directly store the result
+		report.SQLErr = instance.dis.SQL().Backup(io, sql, instance.SqlDatabase)
+	}()
+
+	// TODO: Backup the docker image
+
+	// wait for the group, then close the message channel.
+	go func() {
+		wg.Wait()
+		close(messages)
+	}()
+
+	// print out all the messages
+	for message := range messages {
+		io.Println(message)
+	}
+
+	return
+}

go.sum

@@ -15,8 +15,6 @@ github.com/jinzhu/now v1.1.5 h1:/o9tlHleP7gOFmsnYNz3RGnqzefHA47wQpKrrdTIwXQ=
 github.com/jinzhu/now v1.1.5/go.mod h1:d3SSVoowX0Lcu0IBviAWJpolVfI5UJVZZ7cO71lE/z8=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
-github.com/tkw1536/goprogram v0.0.9 h1:y5bAWbiVRc47TjvpVDmyMtp5CgJXz1ultLOq+v9tfsA=
-github.com/tkw1536/goprogram v0.0.9/go.mod h1:rX9MKOpJ9qAu4jHV2+n64SKmm3c2D3Hh1V8zC1H3jB4=
 github.com/tkw1536/goprogram v0.0.10 h1:NRnAW46Vl9ro01eLDhlb7R56HsCls43h2anNXjwMPP4=
 github.com/tkw1536/goprogram v0.0.10/go.mod h1:rX9MKOpJ9qAu4jHV2+n64SKmm3c2D3Hh1V8zC1H3jB4=
 golang.org/x/exp v0.0.0-20220722155223-a9213eeb770e h1:+WEEuIdZHnUeJJmEUjyYC2gfUMj69yZXw17EnHg/otA=

internal/stack/stack.go

@@ -94,7 +94,7 @@ func (ds Stack) Run(io stream.IOStream, autoRemove bool, service, command string
 	if !io.StdinIsATerminal() {
 		compose = append(compose, "-T")
 	}
-	compose = append(compose, command)
+	compose = append(compose, service, command)
 	compose = append(compose, args...)
 
 	code, err := ds.compose(io, compose...)