1 files changed, 108 insertions, 0 deletions
diff --git a/pkg/state/single_sec.go b/pkg/state/single_sec.go
new file mode 100644
index 0000000..9c69fa8
--- /dev/null
+++ b/pkg/state/single_sec.go
@@ -0,0 +1,108 @@
+package state
+
+import (
+	"context"
+	"crypto"
+	"crypto/ed25519"
+	"fmt"
+	"sync"
+	"time"
+
+	"git.sigsum.org/log-go/pkg/client"
+	"git.sigsum.org/log-go/pkg/db"
+	"git.sigsum.org/sigsum-go/pkg/log"
+	//"git.sigsum.org/sigsum-go/pkg/requests"
+	"git.sigsum.org/sigsum-go/pkg/types"
+)
+
+// StateManagerSingleSecondary implements a single-instance StateManager for secondary nodes
+type StateManagerSingleSecondary struct {
+	client    db.Client
+	signer    crypto.Signer
+	namespace types.Hash
+	interval  time.Duration
+	deadline  time.Duration
+	primary   *client.Client
+
+	// Lock-protected access to pointers.  A write lock is only obtained once
+	// per interval when doing pointer rotation.  All endpoints are readers.
+	sync.RWMutex
+	signedTreeHead *types.SignedTreeHead
+}
+
+func NewStateManagerSingleSecondary(dbcli db.Client, signer crypto.Signer, interval, deadline time.Duration, primurl string, primpk types.PublicKey) (*StateManagerSingleSecondary, error) {
+	sm := &StateManagerSingleSecondary{
+		client:    dbcli,
+		signer:    signer,
+		namespace: *types.HashFn(signer.Public().(ed25519.PublicKey)),
+		interval:  interval,
+		deadline:  deadline,
+		primary:   client.NewClient(primurl, primpk),
+	}
+	sth, err := sm.latestSTH(context.Background())
+	sm.setSignedTreeHead(sth)
+	return sm, err
+}
+
+func (sm *StateManagerSingleSecondary) Run(ctx context.Context) {
+	rotation := func() {
+		nextSTH, err := sm.latestSTH(ctx)
+		if err != nil {
+			log.Warning("cannot rotate without tree head: %v", err)
+			return
+		}
+		sm.rotate(nextSTH)
+	}
+
+	ticker := time.NewTicker(sm.interval)
+	defer ticker.Stop()
+
+	// TODO: fetch leaves from primary
+
+	rotation()
+	for {
+		select {
+		case <-ticker.C:
+			rotation()
+		case <-ctx.Done():
+			return
+		}
+	}
+}
+
+func (sm *StateManagerSingleSecondary) AddCosignature(ctx context.Context, pub *types.PublicKey, sig *types.Signature) error {
+	return fmt.Errorf("internal error: AddCosignature() called in secondary node")
+}
+func (sm *StateManagerSingleSecondary) CosignedTreeHead(_ context.Context) (*types.CosignedTreeHead, error) {
+	return nil, fmt.Errorf("internal error: AddCosignature() called in secondary node")
+}
+func (sm *StateManagerSingleSecondary) ToCosignTreeHead(_ context.Context) (*types.SignedTreeHead, error) {
+	return nil, fmt.Errorf("internal error: AddCosignature() called in secondary node")
+}
+
+func (sm *StateManagerSingleSecondary) setSignedTreeHead(nextSTH *types.SignedTreeHead) {
+	sm.signedTreeHead = nextSTH
+}
+
+func (sm *StateManagerSingleSecondary) latestSTH(ctx context.Context) (*types.SignedTreeHead, error) {
+	ictx, cancel := context.WithTimeout(ctx, sm.deadline)
+	defer cancel()
+
+	th, err := sm.client.GetTreeHead(ictx)
+	if err != nil {
+		return nil, fmt.Errorf("failed fetching tree head: %v", err)
+	}
+	sth, err := th.Sign(sm.signer, &sm.namespace)
+	if err != nil {
+		return nil, fmt.Errorf("failed signing tree head: %v", err)
+	}
+	return sth, nil
+}
+
+func (sm *StateManagerSingleSecondary) rotate(nextSTH *types.SignedTreeHead) {
+	sm.Lock()
+	defer sm.Unlock()
+
+	log.Debug("rotating tree heads")
+	sm.setSignedTreeHead(nextSTH)
+}