hst/instance: define instance state

This is now part of the hst API. This change also improves identifier generation and serialisation.

Signed-off-by: Ophestra <cat@gensokyo.uk>

6 files changed, 24 insertions, 147 deletions

diff --git a/internal/app/state/id.go b/internal/app/state/id.go
deleted file mode 100644
index 11bbc3fe..00000000
--- a/internal/app/state/id.go
+++ /dev/null
@@ -1,48 +0,0 @@
-package state
-
-import (
-	"crypto/rand"
-	"encoding/hex"
-	"errors"
-	"fmt"
-)
-
-type ID [16]byte
-
-var (
-	ErrInvalidLength = errors.New("string representation must have a length of 32")
-)
-
-func (a *ID) String() string {
-	return hex.EncodeToString(a[:])
-}
-
-func NewAppID(id *ID) error {
-	_, err := rand.Read(id[:])
-	return err
-}
-
-func ParseAppID(id *ID, s string) error {
-	if len(s) != 32 {
-		return ErrInvalidLength
-	}
-
-	for i, b := range s {
-		if b < '0' || b > 'f' {
-			return fmt.Errorf("invalid char %q at byte %d", b, i)
-		}
-
-		v := uint8(b)
-		if v > '9' {
-			v = 10 + v - 'a'
-		} else {
-			v -= '0'
-		}
-		if i%2 == 0 {
-			v <<= 4
-		}
-		id[i/2] += v
-	}
-
-	return nil
-}
diff --git a/internal/app/state/id_test.go b/internal/app/state/id_test.go
deleted file mode 100644
index abf2c190..00000000
--- a/internal/app/state/id_test.go
+++ /dev/null
@@ -1,63 +0,0 @@
-package state_test
-
-import (
-	"errors"
-	"testing"
-
-	"hakurei.app/internal/app/state"
-)
-
-func TestParseAppID(t *testing.T) {
-	t.Run("bad length", func(t *testing.T) {
-		if err := state.ParseAppID(new(state.ID), "meow"); !errors.Is(err, state.ErrInvalidLength) {
-			t.Errorf("ParseAppID: error = %v, wantErr =  %v", err, state.ErrInvalidLength)
-		}
-	})
-
-	t.Run("bad byte", func(t *testing.T) {
-		wantErr := "invalid char '\\n' at byte 15"
-		if err := state.ParseAppID(new(state.ID), "02bc7f8936b2af6\n\ne2535cd71ef0bb7"); err == nil || err.Error() != wantErr {
-			t.Errorf("ParseAppID: error = %v, wantErr =  %v", err, wantErr)
-		}
-	})
-
-	t.Run("fuzz 16 iterations", func(t *testing.T) {
-		for i := 0; i < 16; i++ {
-			testParseAppIDWithRandom(t)
-		}
-	})
-}
-
-func FuzzParseAppID(f *testing.F) {
-	for i := 0; i < 16; i++ {
-		id := new(state.ID)
-		if err := state.NewAppID(id); err != nil {
-			panic(err.Error())
-		}
-		f.Add(id[0], id[1], id[2], id[3], id[4], id[5], id[6], id[7], id[8], id[9], id[10], id[11], id[12], id[13], id[14], id[15])
-	}
-
-	f.Fuzz(func(t *testing.T, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15 byte) {
-		testParseAppID(t, &state.ID{b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15})
-	})
-}
-
-func testParseAppIDWithRandom(t *testing.T) {
-	id := new(state.ID)
-	if err := state.NewAppID(id); err != nil {
-		t.Fatalf("cannot generate app ID: %v", err)
-	}
-	testParseAppID(t, id)
-}
-
-func testParseAppID(t *testing.T, id *state.ID) {
-	s := id.String()
-	got := new(state.ID)
-	if err := state.ParseAppID(got, s); err != nil {
-		t.Fatalf("cannot parse app ID: %v", err)
-	}
-
-	if *got != *id {
-		t.Fatalf("ParseAppID(%#v) = \n%#v, want \n%#v", s, got, id)
-	}
-}
diff --git a/internal/app/state/join.go b/internal/app/state/join.go
index 2b4011fe..43a19b1d 100644
--- a/internal/app/state/join.go
+++ b/internal/app/state/join.go
@@ -3,6 +3,8 @@ package state
 import (
 	"errors"
 	"maps"
+
+	"hakurei.app/hst"
 )
 
 var (
@@ -14,20 +16,22 @@ Joiner is the interface that wraps the Join method.
 
 The Join function uses Joiner if available.
 */
-type Joiner interface{ Join() (Entries, error) }
+type Joiner interface {
+	Join() (map[hst.ID]*hst.State, error)
+}
 
-// Join returns joined state entries of all active aids.
-func Join(s Store) (Entries, error) {
+// Join returns joined state entries of all active identities.
+func Join(s Store) (map[hst.ID]*hst.State, error) {
 	if j, ok := s.(Joiner); ok {
 		return j.Join()
 	}
 
 	var (
 		aids    []int
-		entries = make(Entries)
+		entries = make(map[hst.ID]*hst.State)
 
 		el      int
-		res     Entries
+		res     map[hst.ID]*hst.State
 		loadErr error
 	)
 
diff --git a/internal/app/state/multi.go b/internal/app/state/multi.go
index ca608f58..c15b8534 100644
--- a/internal/app/state/multi.go
+++ b/internal/app/state/multi.go
@@ -131,7 +131,7 @@ type multiBackend struct {
 	mu sync.RWMutex
 }
 
-func (b *multiBackend) filename(id *ID) string { return path.Join(b.path, id.String()) }
+func (b *multiBackend) filename(id *hst.ID) string { return path.Join(b.path, id.String()) }
 
 func (b *multiBackend) lockFileAct(lt int) (err error) {
 	op := "LockAct"
@@ -163,7 +163,7 @@ func (b *multiBackend) unlockFile() error { return b.lockFileAct(syscall.LOCK_UN
 
 // reads all launchers in simpleBackend
 // file contents are ignored if decode is false
-func (b *multiBackend) load(decode bool) (Entries, error) {
+func (b *multiBackend) load(decode bool) (map[hst.ID]*hst.State, error) {
 	b.mu.RLock()
 	defer b.mu.RUnlock()
 
@@ -177,15 +177,15 @@ func (b *multiBackend) load(decode bool) (Entries, error) {
 
 	// allocate as if every entry is valid
 	// since that should be the case assuming no external interference happens
-	r := make(Entries, len(entries))
+	r := make(map[hst.ID]*hst.State, len(entries))
 
 	for _, e := range entries {
 		if e.IsDir() {
 			return nil, fmt.Errorf("unexpected directory %q in store", e.Name())
 		}
 
-		var id ID
-		if err := ParseAppID(&id, e.Name()); err != nil {
+		var id hst.ID
+		if err := id.UnmarshalText([]byte(e.Name())); err != nil {
 			return nil, &hst.AppError{Step: "parse state key", Err: err}
 		}
 
@@ -195,7 +195,7 @@ func (b *multiBackend) load(decode bool) (Entries, error) {
 			if f, err := os.Open(path.Join(b.path, e.Name())); err != nil {
 				return &hst.AppError{Step: "open state file", Err: err}
 			} else {
-				var s State
+				var s hst.State
 				r[id] = &s
 
 				// append regardless, but only parse if required, implements Len
@@ -226,7 +226,7 @@ func (b *multiBackend) load(decode bool) (Entries, error) {
 }
 
 // Save writes process state to filesystem
-func (b *multiBackend) Save(state *State) error {
+func (b *multiBackend) Save(state *hst.State) error {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 
@@ -247,7 +247,7 @@ func (b *multiBackend) Save(state *State) error {
 	return nil
 }
 
-func (b *multiBackend) Destroy(id ID) error {
+func (b *multiBackend) Destroy(id hst.ID) error {
 	b.mu.Lock()
 	defer b.mu.Unlock()
 
@@ -257,7 +257,7 @@ func (b *multiBackend) Destroy(id ID) error {
 	return nil
 }
 
-func (b *multiBackend) Load() (Entries, error) { return b.load(true) }
+func (b *multiBackend) Load() (map[hst.ID]*hst.State, error) { return b.load(true) }
 
 func (b *multiBackend) Len() (int, error) {
 	// rn consists of only nil entries but has the correct length
diff --git a/internal/app/state/state.go b/internal/app/state/state.go
index b8d8d255..ef783bfb 100644
--- a/internal/app/state/state.go
+++ b/internal/app/state/state.go
@@ -3,7 +3,6 @@ package state
 
 import (
 	"errors"
-	"time"
 
 	"hakurei.app/hst"
 )
@@ -11,8 +10,6 @@ import (
 // ErrNoConfig is returned by [Cursor] when used with a nil [hst.Config].
 var ErrNoConfig = errors.New("state does not contain config")
 
-type Entries map[ID]*State
-
 type Store interface {
 	// Do calls f exactly once and ensures store exclusivity until f returns.
 	// Returns whether f is called and any errors during the locking process.
@@ -29,21 +26,8 @@ type Store interface {
 
 // Cursor provides access to the store of an identity.
 type Cursor interface {
-	Save(state *State) error
-	Destroy(id ID) error
-	Load() (Entries, error)
+	Save(state *hst.State) error
+	Destroy(id hst.ID) error
+	Load() (map[hst.ID]*hst.State, error)
 	Len() (int, error)
 }
-
-// State is the on-disk state of a container instance.
-type State struct {
-	// Unique instance id, generated by internal/app.
-	ID ID `json:"instance"`
-	// Shim process pid. This runs as the target user.
-	PID int `json:"pid"`
-	// Configuration value used to start the container.
-	Config *hst.Config `json:"config"`
-
-	// Exact point in time that the shim process was created.
-	Time time.Time `json:"time"`
-}
diff --git a/internal/app/state/state_test.go b/internal/app/state/state_test.go
index baada60d..2e191f31 100644
--- a/internal/app/state/state_test.go
+++ b/internal/app/state/state_test.go
@@ -28,7 +28,7 @@ func testStore(t *testing.T, s state.Store) {
 		tl
 	)
 
-	var tc [tl]state.State
+	var tc [tl]hst.State
 	for i := 0; i < tl; i++ {
 		makeState(t, &tc[i])
 	}
@@ -122,8 +122,8 @@ func testStore(t *testing.T, s state.Store) {
 	})
 }
 
-func makeState(t *testing.T, s *state.State) {
-	if err := state.NewAppID(&s.ID); err != nil {
+func makeState(t *testing.T, s *hst.State) {
+	if err := hst.NewInstanceID(&s.ID); err != nil {
 		t.Fatalf("cannot create dummy state: %v", err)
 	}
 	s.PID = rand.Int()