Implement initial 'wdcli backup_instance' command

This commit performs an initial implementation of the 'backup_instance'
command.

env/backup.go

@@ -0,0 +1,52 @@
+package env
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"sync/atomic"
+	"time"
+)
+
+func (dis Distillery) BackupDir() string {
+	return filepath.Join(dis.Config.DeployRoot, "backups")
+}
+
+func (dis Distillery) InprogressBackupPath() string {
+	return filepath.Join(dis.BackupDir(), "inprogress")
+}
+
+func (dis Distillery) FinalBackupPath() string {
+	return filepath.Join(dis.BackupDir(), "final")
+}
+
+// NewFinalBackupFile returns the path to a new final backup file.
+func (dis Distillery) FinalBackupArchive(prefix string) string {
+	counter := atomic.AddUint64(&globalBackupCounter, 1)
+
+	// generate a new name with the current time, a global counter, and the prefix
+	name := fmt.Sprintf("%s-%d-%d.tar.gz", prefix, time.Now().Unix(), counter)
+	path := filepath.Join(dis.FinalBackupPath(), name)
+
+	return path
+}
+
+var globalBackupCounter uint64
+
+// NewInprogressBackupPath returns the path to a new inprogress backup directory.
+// The directory is guaranteed to have been freshly created.
+func (dis Distillery) NewInprogressBackupPath(prefix string) (string, error) {
+	counter := atomic.AddUint64(&globalBackupCounter, 1)
+
+	// generate a new name with the current time, a global counter, and the prefix
+	name := fmt.Sprintf("%s-%d-%d", prefix, time.Now().Unix(), counter)
+	path := filepath.Join(dis.InprogressBackupPath(), name)
+
+	// create the directory
+	if err := os.Mkdir(path, os.ModeDir); err != nil {
+		return "", err
+	}
+
+	// and it is here!
+	return path, nil
+}

env/dirs.go

@@ -1,23 +0,0 @@
-package env
-
-import "path/filepath"
-
-func (dis Distillery) BackupDir() string {
-	return filepath.Join(dis.Config.DeployRoot, "backups")
-}
-
-func (dis Distillery) RuntimeDir() string {
-	return filepath.Join(dis.Config.DeployRoot, "runtime")
-}
-
-func (dis Distillery) RuntimeUtilsDir() string {
-	return filepath.Join(dis.Config.DeployRoot, "runtime", "utils")
-}
-
-func (dis Distillery) InprogressBackupPath() string {
-	return filepath.Join(dis.BackupDir(), "inprogress")
-}
-
-func (dis Distillery) FinalBackupPath() string {
-	return filepath.Join(dis.BackupDir(), "final")
-}

env/instances.go

@@ -30,6 +30,11 @@ var ErrInstanceNotFound = exit.Error{
 	ExitCode: exit.ExitGeneric,
 }
 
+var errSQL = exit.Error{
+	Message:  "Unknown SQL Error %s",
+	ExitCode: exit.ExitGeneric,
+}
+
 // Instance returns the instance of the WissKI Distillery with the provided slug
 func (dis *Distillery) Instance(slug string) (i Instance, err error) {
 	if err := dis.SQLWaitForConnection(); err != nil {

env/runtime.go

@@ -0,0 +1,13 @@
+package env
+
+import "path/filepath"
+
+// RuntimeDir returns the path to the runtime directory
+func (dis Distillery) RuntimeDir() string {
+	return filepath.Join(dis.Config.DeployRoot, "runtime")
+}
+
+// RuntimeUtilsDir returns the path to the runtime utility dir
+func (dis Distillery) RuntimeUtilsDir() string {
+	return filepath.Join(dis.Config.DeployRoot, "runtime", "utils")
+}

env/stack.go

@@ -6,6 +6,8 @@ import (
 	"github.com/FAU-CDI/wisski-distillery/internal/stack"
 )
 
+// TODO: Move everything into specific subpackages
+
 // Stacks returns the Stacks of this distillery
 func (dis *Distillery) Stacks() []stack.Installable {
 	// TODO: Do we want to cache these stacks?

env/stack_sql.go

@@ -2,6 +2,7 @@ package env
 
 import (
 	"fmt"
+	"io"
 	"io/fs"
 	"time"
 
@@ -76,6 +77,22 @@ func (dis *Distillery) sqlBkTable(silent bool) (*gorm.DB, error) {
 	return table, nil
 }
 
+var errSQLBackup = errors.New("SQLBackup: Mysqldump returned non-zero exit code")
+
+// SQLBackup makes a backup of the sql database into dest.
+func (dis *Distillery) SQLBackup(io stream.IOStream, dest io.Writer, database string) error {
+	io = stream.NewIOStream(dest, io.Stderr, nil, 0)
+
+	code, err := dis.SQLStack().Exec(io, "sql", "mysqldump", "--database", database)
+	if err != nil {
+		return err
+	}
+	if code != 0 {
+		return errSQLBackup
+	}
+	return nil
+}
+
 // SQLShell executes a mysql shell inside the SQLStack.
 func (dis *Distillery) SQLShell(io stream.IOStream, argv ...string) (int, error) {
 	return dis.SQLStack().Exec(io, "sql", "mysql", argv...)

env/stack_triplestore.go

@@ -200,6 +200,21 @@ func (dis *Distillery) TriplestorePurgeRepo(repo string) error {
 	return nil
 }
 
+var errTSBackupWrongStatusCode = errors.New("Distillery.Backup: Wrong status code")
+
+// TriplestoreBackup backs up the repository named repo into the writer dst.
+func (dis *Distillery) TriplestoreBackup(dst io.Writer, repo string) (int64, error) {
+	res, err := dis.triplestoreRequest("GET", "/repositories/"+repo+"/statements?infer=false", nil, "", "application/n-quads")
+	if err != nil {
+		return 0, err
+	}
+	if res.StatusCode != http.StatusOK {
+		return 0, errTSBackupWrongStatusCode
+	}
+	defer res.Body.Close()
+	return io.Copy(dst, res.Body)
+}
+
 var errTriplestoreFailedSecurity = errors.New("failed to enable triplestore security: request did not succeed with HTTP 200 OK")
 
 func (dis *Distillery) TriplestoreBootstrap(io stream.IOStream) error {