1 files changed, 33 insertions, 11 deletions
diff --git a/pkg/instance/instance.go b/pkg/instance/instance.go
index f4c0089..78b5d81 100644
--- a/pkg/instance/instance.go
+++ b/pkg/instance/instance.go
@@ -35,22 +35,44 @@ type Instance struct {
 	Signer   crypto.Signer      // provides access to Ed25519 private key
 	Stateman state.StateManager // coordinates access to (co)signed tree heads
 	DNS      dns.Verifier       // checks if domain name knows a public key
+	Role     Role
+	Peer     ServiceEndpoint
+}
+
+type Role int64
+const (
+	Primary Role = iota
+	Secondary
+)
+
+type ServiceEndpoint struct {
+	URL string
+	Pubkey types.PublicKey
 }
 
-// Handlers returns a list of sigsum handlers
 func (i *Instance) Handlers() []Handler {
-	return []Handler{
-		Handler{Instance: i, Handler: addLeaf, Endpoint: types.EndpointAddLeaf, Method: http.MethodPost},
-		Handler{Instance: i, Handler: addCosignature, Endpoint: types.EndpointAddCosignature, Method: http.MethodPost},
-		Handler{Instance: i, Handler: getTreeHeadToCosign, Endpoint: types.EndpointGetTreeHeadToCosign, Method: http.MethodGet},
-		Handler{Instance: i, Handler: getTreeHeadCosigned, Endpoint: types.EndpointGetTreeHeadCosigned, Method: http.MethodGet},
-		Handler{Instance: i, Handler: getCheckpoint, Endpoint: types.Endpoint("get-checkpoint"), Method: http.MethodGet},
-		Handler{Instance: i, Handler: getConsistencyProof, Endpoint: types.EndpointGetConsistencyProof, Method: http.MethodGet},
-		Handler{Instance: i, Handler: getInclusionProof, Endpoint: types.EndpointGetInclusionProof, Method: http.MethodGet},
-		Handler{Instance: i, Handler: getLeaves, Endpoint: types.EndpointGetLeaves, Method: http.MethodGet},
+	switch i.Role {
+	case Primary:
+		return []Handler{
+			Handler{Instance: i, Handler: addLeaf, Endpoint: types.EndpointAddLeaf, Method: http.MethodPost},
+			Handler{Instance: i, Handler: addCosignature, Endpoint: types.EndpointAddCosignature, Method: http.MethodPost},
+			Handler{Instance: i, Handler: getTreeHeadToCosign, Endpoint: types.EndpointGetTreeHeadToCosign, Method: http.MethodGet}, // ToSign -> ToCoSign
+			Handler{Instance: i, Handler: getTreeHeadCosigned, Endpoint: types.EndpointGetTreeHeadCosigned, Method: http.MethodGet},
+			Handler{Instance: i, Handler: getCheckpoint, Endpoint: types.Endpoint("get-checkpoint"), Method: http.MethodGet},
+			Handler{Instance: i, Handler: getConsistencyProof, Endpoint: types.EndpointGetConsistencyProof, Method: http.MethodGet},
+			Handler{Instance: i, Handler: getInclusionProof, Endpoint: types.EndpointGetInclusionProof, Method: http.MethodGet},
+			Handler{Instance: i, Handler: getLeaves, Endpoint: types.EndpointGetLeaves, Method: http.MethodGet},
+		}
+	case Secondary:
+		return []Handler{
+			Handler{Instance: i, Handler: getTreeHeadToCosign, Endpoint: types.EndpointGetSecondaryTreeHead, Method: http.MethodGet},
+		}
+	default:
+		return []Handler{}
 	}
 }
 
+
 // checkHTTPMethod checks if an HTTP method is supported
 func (i *Instance) checkHTTPMethod(m string) bool {
 	return m == http.MethodGet || m == http.MethodPost
@@ -95,7 +117,7 @@ func (i *Instance) cosignatureRequestFromHTTP(r *http.Request) (*requests.Cosign
 func (i *Instance) consistencyProofRequestFromHTTP(r *http.Request) (*requests.ConsistencyProof, error) {
 	var req requests.ConsistencyProof
 	if err := req.FromURL(r.URL.Path); err != nil {
-		return nil, fmt.Errorf("FromASCII: %v", err)
+		return nil, fmt.Errorf("FromURL: %v", err)
 	}
 	if req.OldSize < 1 {
 		return nil, fmt.Errorf("OldSize(%d) must be larger than zero", req.OldSize)