Add extra args for Opts and Runc

This allows additional flags to be added to runc binaries without needing to
update this package each time.

While the typesafe flags are still the primary api for this pkg, this allows an
easier transitional state when new flags are added to underlying runtimes
following the runc CLI.

Signed-off-by: Michael Crosby <michael@thepasture.io>

runc.go

@@ -100,6 +100,7 @@ type CreateOpts struct {
 	NoNewKeyring  bool
 	ExtraFiles    []*os.File
 	Started       chan<- int
+	ExtraArgs     []string
 }
 
 func (o *CreateOpts) args() (out []string, err error) {
@@ -125,6 +126,9 @@ func (o *CreateOpts) args() (out []string, err error) {
 	if o.ExtraFiles != nil {
 		out = append(out, "--preserve-fds", strconv.Itoa(len(o.ExtraFiles)))
 	}
+	if len(o.ExtraArgs) > 0 {
+		out = append(out, o.ExtraArgs...)
+	}
 	return out, nil
 }
 
@@ -182,6 +186,7 @@ type ExecOpts struct {
 	ConsoleSocket ConsoleSocket
 	Detach        bool
 	Started       chan<- int
+	ExtraArgs     []string
 }
 
 func (o *ExecOpts) args() (out []string, err error) {
@@ -198,6 +203,9 @@ func (o *ExecOpts) args() (out []string, err error) {
 		}
 		out = append(out, "--pid-file", abs)
 	}
+	if len(o.ExtraArgs) > 0 {
+		out = append(out, o.ExtraArgs...)
+	}
 	return out, nil
 }
 
@@ -292,13 +300,17 @@ func (r *Runc) Run(context context.Context, id, bundle string, opts *CreateOpts)
 
 // DeleteOpts holds the deletion options for calling `runc delete`
 type DeleteOpts struct {
-	Force bool
+	Force     bool
+	ExtraArgs []string
 }
 
 func (o *DeleteOpts) args() (out []string) {
 	if o.Force {
 		out = append(out, "--force")
 	}
+	if len(o.ExtraArgs) > 0 {
+		out = append(out, o.ExtraArgs...)
+	}
 	return out
 }
 
@@ -313,13 +325,17 @@ func (r *Runc) Delete(context context.Context, id string, opts *DeleteOpts) erro
 
 // KillOpts specifies options for killing a container and its processes
 type KillOpts struct {
-	All bool
+	All       bool
+	ExtraArgs []string
 }
 
 func (o *KillOpts) args() (out []string) {
 	if o.All {
 		out = append(out, "--all")
 	}
+	if len(o.ExtraArgs) > 0 {
+		out = append(out, o.ExtraArgs...)
+	}
 	return out
 }
 
@@ -461,6 +477,7 @@ type CheckpointOpts struct {
 	LazyPages bool
 	// StatusFile is the file criu writes \0 to once lazy-pages is ready
 	StatusFile *os.File
+	ExtraArgs  []string
 }
 
 // CgroupMode defines the cgroup mode used for checkpointing
@@ -509,6 +526,9 @@ func (o *CheckpointOpts) args() (out []string) {
 	if o.LazyPages {
 		out = append(out, "--lazy-pages")
 	}
+	if len(o.ExtraArgs) > 0 {
+		out = append(out, o.ExtraArgs...)
+	}
 	return out
 }
 
@@ -557,6 +577,7 @@ type RestoreOpts struct {
 	NoSubreaper   bool
 	NoPivot       bool
 	ConsoleSocket ConsoleSocket
+	ExtraArgs     []string
 }
 
 func (o *RestoreOpts) args() ([]string, error) {
@@ -580,6 +601,9 @@ func (o *RestoreOpts) args() ([]string, error) {
 	if o.NoSubreaper {
 		out = append(out, "-no-subreaper")
 	}
+	if len(o.ExtraArgs) > 0 {
+		out = append(out, o.ExtraArgs...)
+	}
 	return out, nil
 }
 
@@ -695,6 +719,9 @@ func (r *Runc) args() (out []string) {
 		// nil stands for "auto" (differs from explicit "false")
 		out = append(out, "--rootless="+strconv.FormatBool(*r.Rootless))
 	}
+	if len(r.ExtraArgs) > 0 {
+		out = append(out, r.ExtraArgs...)
+	}
 	return out
 }
 

runc_test.go

@@ -30,7 +30,6 @@ import (
 )
 
 func TestParseVersion(t *testing.T) {
-
 	testParseVersion := func(t *testing.T, input string, expected Version) {
 		actual, err := parseVersion([]byte(input))
 		if err != nil {
@@ -314,3 +313,26 @@ func dummySleepRunc() (_ string, err error) {
 	}
 	return fh.Name(), nil
 }
+
+func TestCreateArgs(t *testing.T) {
+	o := &CreateOpts{}
+	args, err := o.args()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(args) != 0 {
+		t.Fatal("args should be empty")
+	}
+	o.ExtraArgs = []string{"--other"}
+	args, err = o.args()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(args) != 1 {
+		t.Fatal("args should have 1 arg")
+	}
+	if a := args[0]; a != "--other" {
+		t.Fatalf("arg should be --other but got %q", a)
+	}
+
+}

runc_unix.go

@@ -35,4 +35,5 @@ type Runc struct {
 	Criu          string
 	SystemdCgroup bool
 	Rootless      *bool // nil stands for "auto"
+	ExtraArgs     []string
 }