supervisor-go: add ledger package with Append/Read APIs, tests; refactor CLI to use package; update README

kernel/supervisor-go/README.md

@@ -3,12 +3,28 @@
 Runnable stub demonstrating CognitiveOS control-plane concepts without
 an actual LLM.
 
-## Run
+This directory now contains a small ledger package (ledger/) with Append
+and Read APIs and unit tests, plus a tiny CLI demo (main.go) that
+appends route/session/output events to a JSONL ledger.
+
+## Run (demo)
+
+Build or run the CLI:
 
     go run . -ledger ./ledger.jsonl
 
-Then type requests and observe: - deterministic route decision -
+Then type requests and observe the deterministic route decision,
-session_spawn + child_output_received - final_output_emitted
+spawn/output events, and final output. The ledger file will be created
+as JSONL at the path you provide.
+
+## Tests
+
+Run the unit tests for the ledger package:
+
+    go test ./ledger
+
+The tests create a temporary ledger file, append events, and validate
+read-back and hash chaining.
 
 ## Notes
 

kernel/supervisor-go/ledger/ledger.go

@@ -0,0 +1,144 @@
+package ledger
+
+import (
+	"bufio"
+	"crypto/sha256"
+	"encoding/hex"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"sort"
+	"time"
+)
+
+// Event is a single ledger entry stored as JSON per-line (JSONL).
+type Event struct {
+	ID       string                 `json:"id"`
+	TS       string                 `json:"ts"`
+	StreamID string                 `json:"stream_id"`
+	Type     string                 `json:"type"`
+	Body     map[string]any         `json:"body"`
+	PrevHash *string                `json:"prev_hash"`
+	Hash     string                 `json:"hash"`
+}
+
+// Ledger manages append-only JSONL ledger for a single stream.
+// It is intentionally minimal and safe for the demo (not highly concurrent).
+type Ledger struct {
+	Path     string
+	StreamID string
+	LastHash *string
+}
+
+// New returns a Ledger instance. It does not create the file yet.
+func New(path, streamID string) *Ledger {
+	return &Ledger{Path: path, StreamID: streamID, LastHash: nil}
+}
+
+func sha256Hex(b []byte) string {
+	h := sha256.Sum256(b)
+	return hex.EncodeToString(h[:])
+}
+
+func computeHash(id, ts, stream, typ string, body map[string]any, prev *string) (string, error) {
+	env := map[string]any{
+		"id":        id,
+		"ts":        ts,
+		"stream_id": stream,
+		"type":      typ,
+		"body":      body,
+		"prev_hash": prev,
+	}
+	// Best-effort deterministic ordering for body keys.
+	if body != nil {
+		keys := make([]string, 0, len(body))
+		for k := range body {
+			keys = append(keys, k)
+		}
+		sort.Strings(keys)
+		ordered := make(map[string]any, len(body))
+		for _, k := range keys {
+			ordered[k] = body[k]
+		}
+		env["body"] = ordered
+	}
+	b, err := json.Marshal(env)
+	if err != nil {
+		return "", err
+	}
+	return sha256Hex(b), nil
+}
+
+// Append writes a new event to the ledger file and updates LastHash.
+func (l *Ledger) Append(typ string, body map[string]any) (*Event, error) {
+	if l == nil {
+		return nil, errors.New("nil ledger")
+	}
+	id := fmt.Sprintf("%d", time.Now().UnixNano())
+	ts := time.Now().UTC().Format(time.RFC3339Nano)
+	h, err := computeHash(id, ts, l.StreamID, typ, body, l.LastHash)
+	if err != nil {
+		return nil, err
+	}
+	ev := &Event{
+		ID:       id,
+		TS:       ts,
+		StreamID: l.StreamID,
+		Type:     typ,
+		Body:     body,
+		PrevHash: l.LastHash,
+		Hash:     h,
+	}
+	f, err := os.OpenFile(l.Path, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0o644)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	enc := json.NewEncoder(f)
+	if err := enc.Encode(ev); err != nil {
+		return nil, err
+	}
+	l.LastHash = &ev.Hash
+	return ev, nil
+}
+
+// ReadAll reads all events from the ledger file. If the file does not exist, returns empty slice.
+func (l *Ledger) ReadAll() ([]*Event, error) {
+	f, err := os.Open(l.Path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return []*Event{}, nil
+		}
+		return nil, err
+	}
+	defer f.Close()
+	var out []*Event
+	sc := bufio.NewScanner(f)
+	for sc.Scan() {
+		line := sc.Bytes()
+		var ev Event
+		if err := json.Unmarshal(line, &ev); err != nil {
+			return nil, err
+		}
+		out = append(out, &ev)
+	}
+	if err := sc.Err(); err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+// LoadLastHash sets the ledger LastHash to the last entry in the file (if any).
+func (l *Ledger) LoadLastHash() error {
+	evs, err := l.ReadAll()
+	if err != nil {
+		return err
+	}
+	if len(evs) == 0 {
+		l.LastHash = nil
+		return nil
+	}
+	l.LastHash = &evs[len(evs)-1].Hash
+	return nil
+}

kernel/supervisor-go/ledger/ledger_test.go

@@ -0,0 +1,56 @@
+package ledger
+
+import (
+	"os"
+	"testing"
+)
+
+func TestAppendAndRead(t *testing.T) {
+	f, err := os.CreateTemp("", "ledger-test-*.jsonl")
+	if err != nil {
+		t.Fatalf("tempfile: %v", err)
+	}
+	path := f.Name()
+	f.Close()
+	defer os.Remove(path)
+
+	l := New(path, "stream-1")
+	// ensure empty read
+	evs, err := l.ReadAll()
+	if err != nil {
+		t.Fatalf("read empty: %v", err)
+	}
+	if len(evs) != 0 {
+		t.Fatalf("expected 0 events, got %d", len(evs))
+	}
+
+	e1, err := l.Append("route_decision", map[string]any{"tier": "fast"})
+	if err != nil {
+		t.Fatalf("append1: %v", err)
+	}
+	if l.LastHash == nil || *l.LastHash != e1.Hash {
+		t.Fatalf("lasthash not set after append1")
+	}
+
+	e2, err := l.Append("final_output_emitted", map[string]any{"result": "ok"})
+	if err != nil {
+		t.Fatalf("append2: %v", err)
+	}
+	if l.LastHash == nil || *l.LastHash != e2.Hash {
+		t.Fatalf("lasthash not set after append2")
+	}
+	if e2.PrevHash == nil || *e2.PrevHash != e1.Hash {
+		t.Fatalf("prevhash chain broken")
+	}
+
+	evs, err = l.ReadAll()
+	if err != nil {
+		t.Fatalf("read: %v", err)
+	}
+	if len(evs) != 2 {
+		t.Fatalf("expected 2 events, got %d", len(evs))
+	}
+	if evs[0].Hash != e1.Hash || evs[1].Hash != e2.Hash {
+		t.Fatalf("readback hashes mismatch")
+	}
+}

kernel/supervisor-go/main.go

@@ -4,121 +4,20 @@ import (
 	"bufio"
 	"crypto/sha256"
 	"encoding/hex"
-	"encoding/json"
 	"flag"
 	"fmt"
 	"os"
-	"sort"
 	"strings"
 	"time"
+
+	"cognitiveos/supervisor/ledger"
 )
 
-// This is a runnable *stub* for the deterministic control plane.
-// It does NOT call real LLMs. Instead it demonstrates:
-// - deterministic routing (fast/default/heavy)
-// - append-only, hash-chained ledger per "stream"
-// - must-delegate enforcement: router cannot emit without a spawn+child output proof
-
-type Event struct {
-	ID       string                 `json:"id"`
-	TS       string                 `json:"ts"`
-	StreamID string                 `json:"stream_id"`
-	Type     string                 `json:"type"`
-	Body     map[string]any         `json:"body"`
-	PrevHash *string                `json:"prev_hash"`
-	Hash     string                 `json:"hash"`
-}
-
-func canonicalJSON(v any) ([]byte, error) {
-	// Simple canonicalization: marshal with sorted keys for map[string]any at top-level envelope.
-	// For a real system, use a stricter canonical JSON spec.
-	b, err := json.Marshal(v)
-	if err != nil {
-		return nil, err
-	}
-	return b, nil
-}
-
 func sha256Hex(b []byte) string {
 	h := sha256.Sum256(b)
 	return hex.EncodeToString(h[:])
 }
 
-func newID() string {
-	// Not cryptographically strong; good enough for a stub.
-	return fmt.Sprintf("%d-%d", time.Now().UnixNano(), os.Getpid())
-}
-
-func computeHash(id, ts, stream, typ string, body map[string]any, prev *string) (string, error) {
-	env := map[string]any{
-		"id":        id,
-		"ts":        ts,
-		"stream_id": stream,
-		"type":      typ,
-		"body":      body,
-		"prev_hash": prev,
-	}
-	// Sort body keys deterministically (best effort).
-	if body != nil {
-		keys := make([]string, 0, len(body))
-		for k := range body {
-			keys = append(keys, k)
-		}
-		sort.Strings(keys)
-		ordered := make(map[string]any, len(body))
-		for _, k := range keys {
-			ordered[k] = body[k]
-		}
-		env["body"] = ordered
-	}
-	b, err := canonicalJSON(env)
-	if err != nil {
-		return "", err
-	}
-	return sha256Hex(b), nil
-}
-
-type Ledger struct {
-	Path     string
-	StreamID string
-	LastHash *string
-}
-
-func (l *Ledger) Append(typ string, body map[string]any) (*Event, error) {
-	id := newID()
-	ts := time.Now().UTC().Format(time.RFC3339Nano)
-	h, err := computeHash(id, ts, l.StreamID, typ, body, l.LastHash)
-	if err != nil {
-		return nil, err
-	}
-	ev := &Event{
-		ID:       id,
-		TS:       ts,
-		StreamID: l.StreamID,
-		Type:     typ,
-		Body:     body,
-		PrevHash: l.LastHash,
-		Hash:     h,
-	}
-	f, err := os.OpenFile(l.Path, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0o644)
-	if err != nil {
-		return nil, err
-	}
-	defer f.Close()
-
-	enc := json.NewEncoder(f)
-	if err := enc.Encode(ev); err != nil {
-		return nil, err
-	}
-	l.LastHash = &ev.Hash
-	return ev, nil
-}
-
-// Deterministic routing rules (reference):
-// - explicit @fast/@heavy
-// - keywords: one-liner, regex, jq, bash, quick => FAST
-// - multi-file/architecture/restructure/rewrite => HEAVY
-// - else DEFAULT
 func decideRoute(req string) (tier string, agent string, reason string) {
 	l := strings.ToLower(req)
 	if strings.Contains(l, "@fast") {
@@ -141,7 +40,7 @@ func decideRoute(req string) (tier string, agent string, reason string) {
 }
 
 func childWorkerStub(agent string, req string) string {
-	// Placeholder for actual specialist call. This returns deterministic output for demo.
+	// Deterministic placeholder for demo.
 	return fmt.Sprintf("[stub:%s] Received request (%d chars).", agent, len(req))
 }
 
@@ -150,11 +49,12 @@ func main() {
 	flag.Parse()
 
 	routerStream := "router-session-1"
-	ledger := &Ledger{Path: *ledgerPath, StreamID: routerStream, LastHash: nil}
+	l := ledger.New(*ledgerPath, routerStream)
+	// initialize last-hash from existing file if present
+	_ = l.LoadLastHash()
 
-	fmt.Println("CognitiveOS Supervisor (stub). Type a request, then press Enter. Ctrl-D to exit.")
+	fmt.Println("CognitiveOS Supervisor (demo). Type a request, then press Enter. Ctrl-D to exit.")
 	sc := bufio.NewScanner(os.Stdin)
-
 	for sc.Scan() {
 		req := sc.Text()
 		if strings.TrimSpace(req) == "" {
@@ -162,35 +62,32 @@ func main() {
 		}
 
 		tier, agent, reason := decideRoute(req)
-		_, _ = ledger.Append("route_decision", map[string]any{
+		_, _ = l.Append("route_decision", map[string]any{
 			"tier":         tier,
 			"target_agent": agent,
 			"reason":       reason,
 		})
 
-		// session_spawn (must-delegate proof step)
+		childSession := "child-" + fmt.Sprintf("%d", time.Now().UnixNano())
-		childSession := "child-" + newID()
 		payloadHash := sha256Hex([]byte(req))
-		_, _ = ledger.Append("session_spawn", map[string]any{
+		_, _ = l.Append("session_spawn", map[string]any{
 			"child_session": childSession,
 			"child_agent":   agent,
 			"payload_hash":  payloadHash,
 		})
 
-		// child_output_received
 		childOut := childWorkerStub(agent, req)
 		outHash := sha256Hex([]byte(childOut))
-		_, _ = ledger.Append("child_output_received", map[string]any{
+		_, _ = l.Append("child_output_received", map[string]any{
 			"child_session": childSession,
 			"output_hash":   outHash,
 			"output_len":    len(childOut),
 		})
 
-		// emit_guarded (enforced)
 		preamble := fmt.Sprintf("Delegating to %s because %s.", agent, reason)
 		final := preamble + "\n" + childOut
-		_, _ = ledger.Append("final_output_emitted", map[string]any{
+		_, _ = l.Append("final_output_emitted", map[string]any{
-			"proof_ref": "proof-" + newID(),
+			"proof_ref":   "proof-" + fmt.Sprintf("%d", time.Now().UnixNano()),
 			"output_hash": sha256Hex([]byte(final)),
 		})