implement primary and secondary role, for replicationv0.5.0

6 files changed, 0 insertions, 1134 deletions

diff --git a/pkg/instance/experimental.go b/pkg/instance/experimental.go
deleted file mode 100644
index 24feeaf..0000000
--- a/pkg/instance/experimental.go
+++ /dev/null
@@ -1,85 +0,0 @@
-package instance
-
-import (
-	"bytes"
-	"context"
-	"crypto"
-	"crypto/ed25519"
-	"crypto/sha256"
-	"encoding/base64"
-	"encoding/binary"
-	"fmt"
-	"net/http"
-
-	"git.sigsum.org/sigsum-go/pkg/log"
-	"git.sigsum.org/sigsum-go/pkg/types"
-)
-
-// algEd25519 identifies a checkpoint signature algorithm
-const algEd25519 byte = 1
-
-// getCheckpoint is an experimental endpoint that is not part of the official
-// Sigsum API.  Documentation can be found in the transparency-dev repo.
-func getCheckpoint(ctx context.Context, i *Instance, w http.ResponseWriter, r *http.Request) (int, error) {
-	log.Debug("handling get-checkpoint request")
-	sth, err := i.Stateman.ToCosignTreeHead(ctx)
-	if err != nil {
-		return http.StatusInternalServerError, err
-	}
-	if err := i.signWriteNote(w, sth); err != nil {
-		return http.StatusInternalServerError, err
-	}
-	return http.StatusOK, nil
-}
-
-// signWriteNote signs and writes a checkpoint which uses "sigsum.org:<prefix>"
-// as origin string.  Origin string is also used as ID in the note signature.
-// This means that a sigsum log's prefix (say, "glass-frog"), must be unique.
-func (i *Instance) signWriteNote(w http.ResponseWriter, sth *types.SignedTreeHead) error {
-	origin := fmt.Sprintf("sigsum.org:%s", i.Prefix)
-	msg := fmt.Sprintf("%s\n%d\n%s\n",
-		origin,
-		sth.TreeSize,
-		base64.StdEncoding.EncodeToString(sth.RootHash[:]),
-	)
-	sig, err := noteSign(i.Signer, origin, msg)
-	if err != nil {
-		return err
-	}
-
-	fmt.Fprintf(w, "%s\n\u2014 %s %s\n", msg, origin, sig)
-	return nil
-}
-
-// noteSign returns a note signature for the provided origin and message
-func noteSign(signer crypto.Signer, origin, msg string) (string, error) {
-	sig, err := signer.Sign(nil, []byte(msg), crypto.Hash(0))
-	if err != nil {
-		return "", err
-	}
-
-	var hbuf [4]byte
-	binary.BigEndian.PutUint32(hbuf[:], noteKeyHash(origin, notePubKeyEd25519(signer)))
-	sig = append(hbuf[:], sig...)
-	return base64.StdEncoding.EncodeToString(sig), nil
-}
-
-// See:
-// https://cs.opensource.google/go/x/mod/+/refs/tags/v0.5.1:sumdb/note/note.go;l=336
-func notePubKeyEd25519(signer crypto.Signer) []byte {
-	return bytes.Join([][]byte{
-		[]byte{algEd25519},
-		signer.Public().(ed25519.PublicKey),
-	}, nil)
-}
-
-// Source:
-// https://cs.opensource.google/go/x/mod/+/refs/tags/v0.5.1:sumdb/note/note.go;l=222
-func noteKeyHash(name string, key []byte) uint32 {
-	h := sha256.New()
-	h.Write([]byte(name))
-	h.Write([]byte("\n"))
-	h.Write(key)
-	sum := h.Sum(nil)
-	return binary.BigEndian.Uint32(sum)
-}
diff --git a/pkg/instance/handler.go b/pkg/instance/handler.go
deleted file mode 100644
index fa465ee..0000000
--- a/pkg/instance/handler.go
+++ /dev/null
@@ -1,184 +0,0 @@
-package instance
-
-import (
-	"context"
-	"fmt"
-	"net/http"
-	"time"
-
-	"git.sigsum.org/sigsum-go/pkg/log"
-	"git.sigsum.org/sigsum-go/pkg/types"
-)
-
-// Handler implements the http.Handler interface, and contains a reference
-// to a sigsum server instance as well as a function that uses it.
-type Handler struct {
-	Instance *Instance
-	Endpoint types.Endpoint
-	Method   string
-	Handler  func(context.Context, *Instance, http.ResponseWriter, *http.Request) (int, error)
-}
-
-// Path returns a path that should be configured for this handler
-func (h Handler) Path() string {
-	if len(h.Instance.Prefix) == 0 {
-		return h.Endpoint.Path("", "sigsum", "v0")
-	}
-	return h.Endpoint.Path("", h.Instance.Prefix, "sigsum", "v0")
-}
-
-// ServeHTTP is part of the http.Handler interface
-func (h Handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	start := time.Now()
-	code := 0
-	defer func() {
-		end := time.Now().Sub(start).Seconds()
-		sc := fmt.Sprintf("%d", code)
-
-		rspcnt.Inc(h.Instance.LogID, string(h.Endpoint), sc)
-		latency.Observe(end, h.Instance.LogID, string(h.Endpoint), sc)
-	}()
-	reqcnt.Inc(h.Instance.LogID, string(h.Endpoint))
-
-	code = h.verifyMethod(w, r)
-	if code != 0 {
-		return
-	}
-	code = h.handle(w, r)
-}
-
-// verifyMethod checks that an appropriate HTTP method is used.  Error handling
-// is based on RFC 7231, see Sections 6.5.5 (Status 405) and 6.5.1 (Status 400).
-func (h *Handler) verifyMethod(w http.ResponseWriter, r *http.Request) int {
-	if h.Method == r.Method {
-		return 0
-	}
-
-	code := http.StatusBadRequest
-	if ok := h.Instance.checkHTTPMethod(r.Method); ok {
-		w.Header().Set("Allow", h.Method)
-		code = http.StatusMethodNotAllowed
-	}
-
-	http.Error(w, fmt.Sprintf("error=%s", http.StatusText(code)), code)
-	return code
-}
-
-// handle handles an HTTP request for which the HTTP method is already verified
-func (h Handler) handle(w http.ResponseWriter, r *http.Request) int {
-	deadline := time.Now().Add(h.Instance.Deadline)
-	ctx, cancel := context.WithDeadline(r.Context(), deadline)
-	defer cancel()
-
-	code, err := h.Handler(ctx, h.Instance, w, r)
-	if err != nil {
-		log.Debug("%s/%s: %v", h.Instance.Prefix, h.Endpoint, err)
-		http.Error(w, fmt.Sprintf("error=%s", err.Error()), code)
-	}
-	return code
-}
-
-func addLeaf(ctx context.Context, i *Instance, w http.ResponseWriter, r *http.Request) (int, error) {
-	log.Debug("handling add-leaf request")
-	req, err := i.leafRequestFromHTTP(ctx, r)
-	if err != nil {
-		return http.StatusBadRequest, err
-	}
-	if err := i.Client.AddLeaf(ctx, req); err != nil {
-		return http.StatusInternalServerError, err
-	}
-	return http.StatusOK, nil
-}
-
-func addCosignature(ctx context.Context, i *Instance, w http.ResponseWriter, r *http.Request) (int, error) {
-	log.Debug("handling add-cosignature request")
-	req, err := i.cosignatureRequestFromHTTP(r)
-	if err != nil {
-		return http.StatusBadRequest, err
-	}
-	vk := i.Witnesses[req.KeyHash]
-	if err := i.Stateman.AddCosignature(ctx, &vk, &req.Cosignature); err != nil {
-		return http.StatusBadRequest, err
-	}
-	return http.StatusOK, nil
-}
-
-func getTreeHeadToCosign(ctx context.Context, i *Instance, w http.ResponseWriter, _ *http.Request) (int, error) {
-	log.Debug("handling get-tree-head-to-cosign request")
-	sth, err := i.Stateman.ToCosignTreeHead(ctx)
-	if err != nil {
-		return http.StatusInternalServerError, err
-	}
-	if err := sth.ToASCII(w); err != nil {
-		return http.StatusInternalServerError, err
-	}
-	return http.StatusOK, nil
-}
-
-func getTreeHeadCosigned(ctx context.Context, i *Instance, w http.ResponseWriter, _ *http.Request) (int, error) {
-	log.Debug("handling get-tree-head-cosigned request")
-	cth, err := i.Stateman.CosignedTreeHead(ctx)
-	if err != nil {
-		return http.StatusInternalServerError, err
-	}
-	if err := cth.ToASCII(w); err != nil {
-		return http.StatusInternalServerError, err
-	}
-	return http.StatusOK, nil
-}
-
-func getConsistencyProof(ctx context.Context, i *Instance, w http.ResponseWriter, r *http.Request) (int, error) {
-	log.Debug("handling get-consistency-proof request")
-	req, err := i.consistencyProofRequestFromHTTP(r)
-	if err != nil {
-		return http.StatusBadRequest, err
-	}
-	// XXX: check tree size of latest thing we signed?
-
-	proof, err := i.Client.GetConsistencyProof(ctx, req)
-	if err != nil {
-		return http.StatusInternalServerError, err
-	}
-	if err := proof.ToASCII(w); err != nil {
-		return http.StatusInternalServerError, err
-	}
-	return http.StatusOK, nil
-}
-
-func getInclusionProof(ctx context.Context, i *Instance, w http.ResponseWriter, r *http.Request) (int, error) {
-	log.Debug("handling get-inclusion-proof request")
-	req, err := i.inclusionProofRequestFromHTTP(r)
-	if err != nil {
-		return http.StatusBadRequest, err
-	}
-	// XXX: check tree size of latest thing we signed?
-
-	proof, err := i.Client.GetInclusionProof(ctx, req)
-	if err != nil {
-		return http.StatusInternalServerError, err
-	}
-	if err := proof.ToASCII(w); err != nil {
-		return http.StatusInternalServerError, err
-	}
-	return http.StatusOK, nil
-}
-
-func getLeaves(ctx context.Context, i *Instance, w http.ResponseWriter, r *http.Request) (int, error) {
-	log.Debug("handling get-leaves request")
-	req, err := i.leavesRequestFromHTTP(r)
-	if err != nil {
-		return http.StatusBadRequest, err
-	}
-	// XXX: check tree size of latest thing we signed?
-
-	leaves, err := i.Client.GetLeaves(ctx, req)
-	if err != nil {
-		return http.StatusInternalServerError, err
-	}
-	for _, leaf := range *leaves {
-		if err := leaf.ToASCII(w); err != nil {
-			return http.StatusInternalServerError, err
-		}
-	}
-	return http.StatusOK, nil
-}
diff --git a/pkg/instance/handler_test.go b/pkg/instance/handler_test.go
deleted file mode 100644
index 50bd3a4..0000000
--- a/pkg/instance/handler_test.go
+++ /dev/null
@@ -1,688 +0,0 @@
-package instance
-
-import (
-	"bytes"
-	"crypto/ed25519"
-	"crypto/rand"
-	"fmt"
-	"io"
-	"net/http"
-	"net/http/httptest"
-	"reflect"
-	"testing"
-	"time"
-
-	mocksDB "git.sigsum.org/log-go/pkg/db/mocks"
-	mocksDNS "git.sigsum.org/log-go/internal/mocks/dns"
-	mocksState "git.sigsum.org/log-go/pkg/state/mocks"
-	"git.sigsum.org/sigsum-go/pkg/types"
-	"github.com/golang/mock/gomock"
-)
-
-var (
-	testWitVK  = types.PublicKey{}
-	testConfig = Config{
-		LogID:      fmt.Sprintf("%x", types.HashFn([]byte("logid"))[:]),
-		TreeID:     0,
-		Prefix:     "testonly",
-		MaxRange:   3,
-		Deadline:   10,
-		Interval:   10,
-		ShardStart: 10,
-		Witnesses: map[types.Hash]types.PublicKey{
-			*types.HashFn(testWitVK[:]): testWitVK,
-		},
-	}
-	testSTH = &types.SignedTreeHead{
-		TreeHead: types.TreeHead{
-			Timestamp: 0,
-			TreeSize:  0,
-			RootHash:  *types.HashFn([]byte("root hash")),
-		},
-		Signature: types.Signature{},
-	}
-	testCTH = &types.CosignedTreeHead{
-		SignedTreeHead: *testSTH,
-		Cosignature:    []types.Signature{types.Signature{}},
-		KeyHash:        []types.Hash{types.Hash{}},
-	}
-)
-
-// TestHandlers check that the expected handlers are configured
-func TestHandlers(t *testing.T) {
-	endpoints := map[types.Endpoint]bool{
-		types.EndpointAddLeaf:             false,
-		types.EndpointAddCosignature:      false,
-		types.EndpointGetTreeHeadToCosign: false,
-		types.EndpointGetTreeHeadCosigned: false,
-		types.EndpointGetConsistencyProof: false,
-		types.EndpointGetInclusionProof:   false,
-		types.EndpointGetLeaves:           false,
-		types.Endpoint("get-checkpoint"):  false,
-	}
-	i := &Instance{
-		Config: testConfig,
-	}
-	for _, handler := range i.Handlers() {
-		if _, ok := endpoints[handler.Endpoint]; !ok {
-			t.Errorf("got unexpected endpoint: %s", handler.Endpoint)
-		}
-		endpoints[handler.Endpoint] = true
-	}
-	for endpoint, ok := range endpoints {
-		if !ok {
-			t.Errorf("endpoint %s is not configured", endpoint)
-		}
-	}
-}
-
-func TestVerifyMethod(t *testing.T) {
-	badMethod := http.MethodHead
-	instance := Instance{Config: testConfig}
-	for _, handler := range instance.Handlers() {
-		for _, method := range []string{
-			http.MethodGet,
-			http.MethodPost,
-			badMethod,
-		} {
-			url := handler.Endpoint.Path("http://log.example.com", instance.Prefix)
-			req, err := http.NewRequest(method, url, nil)
-			if err != nil {
-				t.Fatalf("must create HTTP request: %v", err)
-			}
-
-			w := httptest.NewRecorder()
-			code := handler.verifyMethod(w, req)
-			if got, want := code == 0, handler.Method == method; got != want {
-				t.Errorf("%s %s: got %v but wanted %v: %v", method, url, got, want, err)
-				continue
-			}
-			if code == 0 {
-				continue
-			}
-
-			if method == badMethod {
-				if got, want := code, http.StatusBadRequest; got != want {
-					t.Errorf("%s %s: got status %d, wanted %d", method, url, got, want)
-				}
-				if _, ok := w.Header()["Allow"]; ok {
-					t.Errorf("%s %s: got Allow header, wanted none", method, url)
-				}
-				continue
-			}
-
-			if got, want := code, http.StatusMethodNotAllowed; got != want {
-				t.Errorf("%s %s: got status %d, wanted %d", method, url, got, want)
-			} else if methods, ok := w.Header()["Allow"]; !ok {
-				t.Errorf("%s %s: got no allow header, expected one", method, url)
-			} else if got, want := len(methods), 1; got != want {
-				t.Errorf("%s %s: got %d allowed method(s), wanted %d", method, url, got, want)
-			} else if got, want := methods[0], handler.Method; got != want {
-				t.Errorf("%s %s: got allowed method %s, wanted %s", method, url, got, want)
-			}
-		}
-	}
-}
-
-// TestPath checks that Path works for an endpoint (add-leaf)
-func TestPath(t *testing.T) {
-	for _, table := range []struct {
-		description string
-		prefix      string
-		want        string
-	}{
-		{
-			description: "no prefix",
-			want:        "/sigsum/v0/add-leaf",
-		},
-		{
-			description: "a prefix",
-			prefix:      "test-prefix",
-			want:        "/test-prefix/sigsum/v0/add-leaf",
-		},
-	} {
-		instance := &Instance{
-			Config: Config{
-				Prefix: table.prefix,
-			},
-		}
-		handler := Handler{
-			Instance: instance,
-			Handler:  addLeaf,
-			Endpoint: types.EndpointAddLeaf,
-			Method:   http.MethodPost,
-		}
-		if got, want := handler.Path(), table.want; got != want {
-			t.Errorf("got path %v but wanted %v", got, want)
-		}
-	}
-}
-
-func TestAddLeaf(t *testing.T) {
-	for _, table := range []struct {
-		description    string
-		ascii          io.Reader // buffer used to populate HTTP request
-		expectTrillian bool      // expect Trillian client code path
-		errTrillian    error     // error from Trillian client
-		expectDNS      bool      // expect DNS verifier code path
-		errDNS         error     // error from DNS verifier
-		wantCode       int       // HTTP status ok
-	}{
-		{
-			description: "invalid: bad request (parser error)",
-			ascii:       bytes.NewBufferString("key=value\n"),
-			wantCode:    http.StatusBadRequest,
-		},
-		{
-			description: "invalid: bad request (signature error)",
-			ascii:       mustLeafBuffer(t, 10, types.Hash{}, false),
-			wantCode:    http.StatusBadRequest,
-		},
-		{
-			description: "invalid: bad request (shard hint is before shard start)",
-			ascii:       mustLeafBuffer(t, 9, types.Hash{}, true),
-			wantCode:    http.StatusBadRequest,
-		},
-		{
-			description: "invalid: bad request (shard hint is after shard end)",
-			ascii:       mustLeafBuffer(t, uint64(time.Now().Unix())+1024, types.Hash{}, true),
-			wantCode:    http.StatusBadRequest,
-		},
-		{
-			description: "invalid: failed verifying domain hint",
-			ascii:       mustLeafBuffer(t, 10, types.Hash{}, true),
-			expectDNS:   true,
-			errDNS:      fmt.Errorf("something went wrong"),
-			wantCode:    http.StatusBadRequest,
-		},
-		{
-			description:    "invalid: backend failure",
-			ascii:          mustLeafBuffer(t, 10, types.Hash{}, true),
-			expectDNS:      true,
-			expectTrillian: true,
-			errTrillian:    fmt.Errorf("something went wrong"),
-			wantCode:       http.StatusInternalServerError,
-		},
-		{
-			description:    "valid",
-			ascii:          mustLeafBuffer(t, 10, types.Hash{}, true),
-			expectDNS:      true,
-			expectTrillian: true,
-			wantCode:       http.StatusOK,
-		},
-	} {
-		// Run deferred functions at the end of each iteration
-		func() {
-			ctrl := gomock.NewController(t)
-			defer ctrl.Finish()
-			dns := mocksDNS.NewMockVerifier(ctrl)
-			if table.expectDNS {
-				dns.EXPECT().Verify(gomock.Any(), gomock.Any(), gomock.Any()).Return(table.errDNS)
-			}
-			client := mocksDB.NewMockClient(ctrl)
-			if table.expectTrillian {
-				client.EXPECT().AddLeaf(gomock.Any(), gomock.Any()).Return(table.errTrillian)
-			}
-			i := Instance{
-				Config: testConfig,
-				Client: client,
-				DNS:    dns,
-			}
-
-			// Create HTTP request
-			url := types.EndpointAddLeaf.Path("http://example.com", i.Prefix)
-			req, err := http.NewRequest("POST", url, table.ascii)
-			if err != nil {
-				t.Fatalf("must create http request: %v", err)
-			}
-
-			// Run HTTP request
-			w := httptest.NewRecorder()
-			mustHandle(t, i, types.EndpointAddLeaf).ServeHTTP(w, req)
-			if got, want := w.Code, table.wantCode; got != want {
-				t.Errorf("got HTTP status code %v but wanted %v in test %q", got, want, table.description)
-			}
-		}()
-	}
-}
-
-func TestAddCosignature(t *testing.T) {
-	buf := func() io.Reader {
-		return bytes.NewBufferString(fmt.Sprintf("%s=%x\n%s=%x\n",
-			"cosignature", types.Signature{},
-			"key_hash", *types.HashFn(testWitVK[:]),
-		))
-	}
-	for _, table := range []struct {
-		description string
-		ascii       io.Reader // buffer used to populate HTTP request
-		expect      bool      // set if a mock answer is expected
-		err         error     // error from Trillian client
-		wantCode    int       // HTTP status ok
-	}{
-		{
-			description: "invalid: bad request (parser error)",
-			ascii:       bytes.NewBufferString("key=value\n"),
-			wantCode:    http.StatusBadRequest,
-		},
-		{
-			description: "invalid: bad request (unknown witness)",
-			ascii: bytes.NewBufferString(fmt.Sprintf("%s=%x\n%s=%x\n",
-				"cosignature", types.Signature{},
-				"key_hash", *types.HashFn(testWitVK[1:]),
-			)),
-			wantCode: http.StatusBadRequest,
-		},
-		{
-			description: "invalid: backend failure",
-			ascii:       buf(),
-			expect:      true,
-			err:         fmt.Errorf("something went wrong"),
-			wantCode:    http.StatusBadRequest,
-		},
-		{
-			description: "valid",
-			ascii:       buf(),
-			expect:      true,
-			wantCode:    http.StatusOK,
-		},
-	} {
-		// Run deferred functions at the end of each iteration
-		func() {
-			ctrl := gomock.NewController(t)
-			defer ctrl.Finish()
-			stateman := mocksState.NewMockStateManager(ctrl)
-			if table.expect {
-				stateman.EXPECT().AddCosignature(gomock.Any(), gomock.Any(), gomock.Any()).Return(table.err)
-			}
-			i := Instance{
-				Config:   testConfig,
-				Stateman: stateman,
-			}
-
-			// Create HTTP request
-			url := types.EndpointAddCosignature.Path("http://example.com", i.Prefix)
-			req, err := http.NewRequest("POST", url, table.ascii)
-			if err != nil {
-				t.Fatalf("must create http request: %v", err)
-			}
-
-			// Run HTTP request
-			w := httptest.NewRecorder()
-			mustHandle(t, i, types.EndpointAddCosignature).ServeHTTP(w, req)
-			if got, want := w.Code, table.wantCode; got != want {
-				t.Errorf("got HTTP status code %v but wanted %v in test %q", got, want, table.description)
-			}
-		}()
-	}
-}
-
-func TestGetTreeToSign(t *testing.T) {
-	for _, table := range []struct {
-		description string
-		expect      bool                  // set if a mock answer is expected
-		rsp         *types.SignedTreeHead // signed tree head from Trillian client
-		err         error                 // error from Trillian client
-		wantCode    int                   // HTTP status ok
-	}{
-		{
-			description: "invalid: backend failure",
-			expect:      true,
-			err:         fmt.Errorf("something went wrong"),
-			wantCode:    http.StatusInternalServerError,
-		},
-		{
-			description: "valid",
-			expect:      true,
-			rsp:         testSTH,
-			wantCode:    http.StatusOK,
-		},
-	} {
-		// Run deferred functions at the end of each iteration
-		func() {
-			ctrl := gomock.NewController(t)
-			defer ctrl.Finish()
-			stateman := mocksState.NewMockStateManager(ctrl)
-			if table.expect {
-				stateman.EXPECT().ToCosignTreeHead(gomock.Any()).Return(table.rsp, table.err)
-			}
-			i := Instance{
-				Config:   testConfig,
-				Stateman: stateman,
-			}
-
-			// Create HTTP request
-			url := types.EndpointGetTreeHeadToCosign.Path("http://example.com", i.Prefix)
-			req, err := http.NewRequest("GET", url, nil)
-			if err != nil {
-				t.Fatalf("must create http request: %v", err)
-			}
-
-			// Run HTTP request
-			w := httptest.NewRecorder()
-			mustHandle(t, i, types.EndpointGetTreeHeadToCosign).ServeHTTP(w, req)
-			if got, want := w.Code, table.wantCode; got != want {
-				t.Errorf("got HTTP status code %v but wanted %v in test %q", got, want, table.description)
-			}
-		}()
-	}
-}
-
-func TestGetTreeCosigned(t *testing.T) {
-	for _, table := range []struct {
-		description string
-		expect      bool                    // set if a mock answer is expected
-		rsp         *types.CosignedTreeHead // cosigned tree head from Trillian client
-		err         error                   // error from Trillian client
-		wantCode    int                     // HTTP status ok
-	}{
-		{
-			description: "invalid: backend failure",
-			expect:      true,
-			err:         fmt.Errorf("something went wrong"),
-			wantCode:    http.StatusInternalServerError,
-		},
-		{
-			description: "valid",
-			expect:      true,
-			rsp:         testCTH,
-			wantCode:    http.StatusOK,
-		},
-	} {
-		// Run deferred functions at the end of each iteration
-		func() {
-			ctrl := gomock.NewController(t)
-			defer ctrl.Finish()
-			stateman := mocksState.NewMockStateManager(ctrl)
-			if table.expect {
-				stateman.EXPECT().CosignedTreeHead(gomock.Any()).Return(table.rsp, table.err)
-			}
-			i := Instance{
-				Config:   testConfig,
-				Stateman: stateman,
-			}
-
-			// Create HTTP request
-			url := types.EndpointGetTreeHeadCosigned.Path("http://example.com", i.Prefix)
-			req, err := http.NewRequest("GET", url, nil)
-			if err != nil {
-				t.Fatalf("must create http request: %v", err)
-			}
-
-			// Run HTTP request
-			w := httptest.NewRecorder()
-			mustHandle(t, i, types.EndpointGetTreeHeadCosigned).ServeHTTP(w, req)
-			if got, want := w.Code, table.wantCode; got != want {
-				t.Errorf("got HTTP status code %v but wanted %v in test %q", got, want, table.description)
-			}
-		}()
-	}
-}
-
-func TestGetConsistencyProof(t *testing.T) {
-	for _, table := range []struct {
-		description string
-		params      string                  // params is the query's url params
-		expect      bool                    // set if a mock answer is expected
-		rsp         *types.ConsistencyProof // consistency proof from Trillian client
-		err         error                   // error from Trillian client
-		wantCode    int                     // HTTP status ok
-	}{
-		{
-			description: "invalid: bad request (parser error)",
-			params:      "a/1",
-			wantCode:    http.StatusBadRequest,
-		},
-		{
-			description: "invalid: bad request (OldSize is zero)",
-			params:      "0/1",
-			wantCode:    http.StatusBadRequest,
-		},
-		{
-			description: "invalid: bad request (OldSize > NewSize)",
-			params:      "2/1",
-			wantCode:    http.StatusBadRequest,
-		},
-		{
-			description: "invalid: backend failure",
-			params:      "1/2",
-			expect:      true,
-			err:         fmt.Errorf("something went wrong"),
-			wantCode:    http.StatusInternalServerError,
-		},
-		{
-			description: "valid",
-			params:      "1/2",
-			expect:      true,
-			rsp: &types.ConsistencyProof{
-				OldSize: 1,
-				NewSize: 2,
-				Path: []types.Hash{
-					*types.HashFn([]byte{}),
-				},
-			},
-			wantCode: http.StatusOK,
-		},
-	} {
-		// Run deferred functions at the end of each iteration
-		func() {
-			ctrl := gomock.NewController(t)
-			defer ctrl.Finish()
-			client := mocksDB.NewMockClient(ctrl)
-			if table.expect {
-				client.EXPECT().GetConsistencyProof(gomock.Any(), gomock.Any()).Return(table.rsp, table.err)
-			}
-			i := Instance{
-				Config: testConfig,
-				Client: client,
-			}
-
-			// Create HTTP request
-			url := types.EndpointGetConsistencyProof.Path("http://example.com", i.Prefix)
-			req, err := http.NewRequest(http.MethodGet, url+table.params, nil)
-			if err != nil {
-				t.Fatalf("must create http request: %v", err)
-			}
-
-			// Run HTTP request
-			w := httptest.NewRecorder()
-			mustHandle(t, i, types.EndpointGetConsistencyProof).ServeHTTP(w, req)
-			if got, want := w.Code, table.wantCode; got != want {
-				t.Errorf("got HTTP status code %v but wanted %v in test %q", got, want, table.description)
-			}
-		}()
-	}
-}
-
-func TestGetInclusionProof(t *testing.T) {
-	for _, table := range []struct {
-		description string
-		params      string                // params is the query's url params
-		expect      bool                  // set if a mock answer is expected
-		rsp         *types.InclusionProof // inclusion proof from Trillian client
-		err         error                 // error from Trillian client
-		wantCode    int                   // HTTP status ok
-	}{
-		{
-			description: "invalid: bad request (parser error)",
-			params:      "a/0000000000000000000000000000000000000000000000000000000000000000",
-			wantCode:    http.StatusBadRequest,
-		},
-		{
-			description: "invalid: bad request (no proof for tree size)",
-			params:      "1/0000000000000000000000000000000000000000000000000000000000000000",
-			wantCode:    http.StatusBadRequest,
-		},
-		{
-			description: "invalid: backend failure",
-			params:      "2/0000000000000000000000000000000000000000000000000000000000000000",
-			expect:      true,
-			err:         fmt.Errorf("something went wrong"),
-			wantCode:    http.StatusInternalServerError,
-		},
-		{
-			description: "valid",
-			params:      "2/0000000000000000000000000000000000000000000000000000000000000000",
-			expect:      true,
-			rsp: &types.InclusionProof{
-				TreeSize:  2,
-				LeafIndex: 0,
-				Path: []types.Hash{
-					*types.HashFn([]byte{}),
-				},
-			},
-			wantCode: http.StatusOK,
-		},
-	} {
-		// Run deferred functions at the end of each iteration
-		func() {
-			ctrl := gomock.NewController(t)
-			defer ctrl.Finish()
-			client := mocksDB.NewMockClient(ctrl)
-			if table.expect {
-				client.EXPECT().GetInclusionProof(gomock.Any(), gomock.Any()).Return(table.rsp, table.err)
-			}
-			i := Instance{
-				Config: testConfig,
-				Client: client,
-			}
-
-			// Create HTTP request
-			url := types.EndpointGetInclusionProof.Path("http://example.com", i.Prefix)
-			req, err := http.NewRequest(http.MethodGet, url+table.params, nil)
-			if err != nil {
-				t.Fatalf("must create http request: %v", err)
-			}
-
-			// Run HTTP request
-			w := httptest.NewRecorder()
-			mustHandle(t, i, types.EndpointGetInclusionProof).ServeHTTP(w, req)
-			if got, want := w.Code, table.wantCode; got != want {
-				t.Errorf("got HTTP status code %v but wanted %v in test %q", got, want, table.description)
-			}
-		}()
-	}
-}
-
-func TestGetLeaves(t *testing.T) {
-	for _, table := range []struct {
-		description string
-		params      string        // params is the query's url params
-		expect      bool          // set if a mock answer is expected
-		rsp         *types.Leaves // list of leaves from Trillian client
-		err         error         // error from Trillian client
-		wantCode    int           // HTTP status ok
-	}{
-		{
-			description: "invalid: bad request (parser error)",
-			params:      "a/1",
-			wantCode:    http.StatusBadRequest,
-		},
-		{
-			description: "invalid: bad request (StartSize > EndSize)",
-			params:      "1/0",
-			wantCode:    http.StatusBadRequest,
-		},
-		{
-			description: "invalid: backend failure",
-			params:      "0/0",
-			expect:      true,
-			err:         fmt.Errorf("something went wrong"),
-			wantCode:    http.StatusInternalServerError,
-		},
-		{
-			description: "valid: one more entry than the configured MaxRange",
-			params:      fmt.Sprintf("%d/%d", 0, testConfig.MaxRange), // query will be pruned
-			expect:      true,
-			rsp: func() *types.Leaves {
-				var list types.Leaves
-				for i := int64(0); i < testConfig.MaxRange; i++ {
-					list = append(list[:], types.Leaf{
-						Statement: types.Statement{
-							ShardHint: 0,
-							Checksum:  types.Hash{},
-						},
-						Signature: types.Signature{},
-						KeyHash:   types.Hash{},
-					})
-				}
-				return &list
-			}(),
-			wantCode: http.StatusOK,
-		},
-	} {
-		// Run deferred functions at the end of each iteration
-		func() {
-			ctrl := gomock.NewController(t)
-			defer ctrl.Finish()
-			client := mocksDB.NewMockClient(ctrl)
-			if table.expect {
-				client.EXPECT().GetLeaves(gomock.Any(), gomock.Any()).Return(table.rsp, table.err)
-			}
-			i := Instance{
-				Config: testConfig,
-				Client: client,
-			}
-
-			// Create HTTP request
-			url := types.EndpointGetLeaves.Path("http://example.com", i.Prefix)
-			req, err := http.NewRequest(http.MethodGet, url+table.params, nil)
-			if err != nil {
-				t.Fatalf("must create http request: %v", err)
-			}
-
-			// Run HTTP request
-			w := httptest.NewRecorder()
-			mustHandle(t, i, types.EndpointGetLeaves).ServeHTTP(w, req)
-			if got, want := w.Code, table.wantCode; got != want {
-				t.Errorf("got HTTP status code %v but wanted %v in test %q", got, want, table.description)
-			}
-			if w.Code != http.StatusOK {
-				return
-			}
-
-			list := types.Leaves{}
-			if err := list.FromASCII(w.Body); err != nil {
-				t.Fatalf("must unmarshal leaf list: %v", err)
-			}
-			if got, want := &list, table.rsp; !reflect.DeepEqual(got, want) {
-				t.Errorf("got leaf list\n\t%v\nbut wanted\n\t%v\nin test %q", got, want, table.description)
-			}
-		}()
-	}
-}
-
-func mustHandle(t *testing.T, i Instance, e types.Endpoint) Handler {
-	for _, handler := range i.Handlers() {
-		if handler.Endpoint == e {
-			return handler
-		}
-	}
-	t.Fatalf("must handle endpoint: %v", e)
-	return Handler{}
-}
-
-func mustLeafBuffer(t *testing.T, shardHint uint64, message types.Hash, wantSig bool) io.Reader {
-	t.Helper()
-
-	vk, sk, err := ed25519.GenerateKey(rand.Reader)
-	if err != nil {
-		t.Fatalf("must generate ed25519 keys: %v", err)
-	}
-	msg := types.Statement{
-		ShardHint: shardHint,
-		Checksum:  *types.HashFn(message[:]),
-	}
-	sig := ed25519.Sign(sk, msg.ToBinary())
-	if !wantSig {
-		sig[0] += 1
-	}
-	return bytes.NewBufferString(fmt.Sprintf(
-		"%s=%d\n"+"%s=%x\n"+"%s=%x\n"+"%s=%x\n"+"%s=%s\n",
-		"shard_hint", shardHint,
-		"message", message[:],
-		"signature", sig,
-		"public_key", vk,
-		"domain_hint", "example.com",
-	))
-}
diff --git a/pkg/instance/instance.go b/pkg/instance/instance.go
deleted file mode 100644
index f4c0089..0000000
--- a/pkg/instance/instance.go
+++ /dev/null
@@ -1,135 +0,0 @@
-package instance
-
-import (
-	"context"
-	"crypto"
-	"fmt"
-	"net/http"
-	"time"
-
-	"git.sigsum.org/log-go/pkg/db"
-	"git.sigsum.org/log-go/pkg/state"
-	"git.sigsum.org/sigsum-go/pkg/dns"
-	"git.sigsum.org/sigsum-go/pkg/requests"
-	"git.sigsum.org/sigsum-go/pkg/types"
-)
-
-// Config is a collection of log parameters
-type Config struct {
-	LogID      string        // H(public key), then hex-encoded
-	TreeID     int64         // Merkle tree identifier used by Trillian
-	Prefix     string        // The portion between base URL and st/v0 (may be "")
-	MaxRange   int64         // Maximum number of leaves per get-leaves request
-	Deadline   time.Duration // Deadline used for gRPC requests
-	Interval   time.Duration // Cosigning frequency
-	ShardStart uint64        // Shard interval start (num seconds since UNIX epoch)
-
-	// Witnesses map trusted witness identifiers to public keys
-	Witnesses map[types.Hash]types.PublicKey
-}
-
-// Instance is an instance of the log's front-end
-type Instance struct {
-	Config                      // configuration parameters
-	Client   db.Client          // provides access to the Trillian backend
-	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
-}
-
-// 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},
-	}
-}
-
-// checkHTTPMethod checks if an HTTP method is supported
-func (i *Instance) checkHTTPMethod(m string) bool {
-	return m == http.MethodGet || m == http.MethodPost
-}
-
-func (i *Instance) leafRequestFromHTTP(ctx context.Context, r *http.Request) (*requests.Leaf, error) {
-	var req requests.Leaf
-	if err := req.FromASCII(r.Body); err != nil {
-		return nil, fmt.Errorf("FromASCII: %v", err)
-	}
-	stmt := types.Statement{
-		ShardHint: req.ShardHint,
-		Checksum:  *types.HashFn(req.Message[:]),
-	}
-	if !stmt.Verify(&req.PublicKey, &req.Signature) {
-		return nil, fmt.Errorf("invalid signature")
-	}
-	shardEnd := uint64(time.Now().Unix())
-	if req.ShardHint < i.ShardStart {
-		return nil, fmt.Errorf("invalid shard hint: %d not in [%d, %d]", req.ShardHint, i.ShardStart, shardEnd)
-	}
-	if req.ShardHint > shardEnd {
-		return nil, fmt.Errorf("invalid shard hint: %d not in [%d, %d]", req.ShardHint, i.ShardStart, shardEnd)
-	}
-	if err := i.DNS.Verify(ctx, req.DomainHint, &req.PublicKey); err != nil {
-		return nil, fmt.Errorf("invalid domain hint: %v", err)
-	}
-	return &req, nil
-}
-
-func (i *Instance) cosignatureRequestFromHTTP(r *http.Request) (*requests.Cosignature, error) {
-	var req requests.Cosignature
-	if err := req.FromASCII(r.Body); err != nil {
-		return nil, fmt.Errorf("FromASCII: %v", err)
-	}
-	if _, ok := i.Witnesses[req.KeyHash]; !ok {
-		return nil, fmt.Errorf("Unknown witness: %x", req.KeyHash)
-	}
-	return &req, nil
-}
-
-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)
-	}
-	if req.OldSize < 1 {
-		return nil, fmt.Errorf("OldSize(%d) must be larger than zero", req.OldSize)
-	}
-	if req.NewSize <= req.OldSize {
-		return nil, fmt.Errorf("NewSize(%d) must be larger than OldSize(%d)", req.NewSize, req.OldSize)
-	}
-	return &req, nil
-}
-
-func (i *Instance) inclusionProofRequestFromHTTP(r *http.Request) (*requests.InclusionProof, error) {
-	var req requests.InclusionProof
-	if err := req.FromURL(r.URL.Path); err != nil {
-		return nil, fmt.Errorf("FromASCII: %v", err)
-	}
-	if req.TreeSize < 2 {
-		// TreeSize:0 => not possible to prove inclusion of anything
-		// TreeSize:1 => you don't need an inclusion proof (it is always empty)
-		return nil, fmt.Errorf("TreeSize(%d) must be larger than one", req.TreeSize)
-	}
-	return &req, nil
-}
-
-func (i *Instance) leavesRequestFromHTTP(r *http.Request) (*requests.Leaves, error) {
-	var req requests.Leaves
-	if err := req.FromURL(r.URL.Path); err != nil {
-		return nil, fmt.Errorf("FromASCII: %v", err)
-	}
-
-	if req.StartSize > req.EndSize {
-		return nil, fmt.Errorf("StartSize(%d) must be less than or equal to EndSize(%d)", req.StartSize, req.EndSize)
-	}
-	if req.EndSize-req.StartSize+1 > uint64(i.MaxRange) {
-		req.EndSize = req.StartSize + uint64(i.MaxRange) - 1
-	}
-	return &req, nil
-}
diff --git a/pkg/instance/instance_test.go b/pkg/instance/instance_test.go
deleted file mode 100644
index 00d996d..0000000
--- a/pkg/instance/instance_test.go
+++ /dev/null
@@ -1,23 +0,0 @@
-package instance
-
-import (
-	"net/http"
-	"testing"
-)
-
-func CheckHTTPMethod(t *testing.T) {
-	var instance Instance
-	for _, table := range []struct {
-		method string
-		wantOK bool
-	}{
-		{wantOK: false, method: http.MethodHead},
-		{wantOK: true, method: http.MethodPost},
-		{wantOK: true, method: http.MethodGet},
-	} {
-		ok := instance.checkHTTPMethod(table.method)
-		if got, want := ok, table.wantOK; got != want {
-			t.Errorf("%s: got %v but wanted %v", table.method, got, want)
-		}
-	}
-}
diff --git a/pkg/instance/metric.go b/pkg/instance/metric.go
deleted file mode 100644
index cbd0223..0000000
--- a/pkg/instance/metric.go
+++ /dev/null
@@ -1,19 +0,0 @@
-package instance
-
-import (
-	"github.com/google/trillian/monitoring"
-	"github.com/google/trillian/monitoring/prometheus"
-)
-
-var (
-	reqcnt  monitoring.Counter   // number of incoming http requests
-	rspcnt  monitoring.Counter   // number of valid http responses
-	latency monitoring.Histogram // request-response latency
-)
-
-func init() {
-	mf := prometheus.MetricFactory{}
-	reqcnt = mf.NewCounter("http_req", "number of http requests", "logid", "endpoint")
-	rspcnt = mf.NewCounter("http_rsp", "number of http requests", "logid", "endpoint", "status")
-	latency = mf.NewHistogram("http_latency", "http request-response latency", "logid", "endpoint", "status")
-}