Add boilerplate for key server APIs (#1196)

Also add a README which outilnes how things will work.

8 files changed, 264 insertions, 95 deletions

diff --git a/keyserver/README.md b/keyserver/README.md
new file mode 100644
index 00000000..fd9f37d2
--- /dev/null
+++ b/keyserver/README.md
@@ -0,0 +1,19 @@
+## Key Server
+
+This is an internal component which manages E2E keys from clients. It handles all the [Key Management APIs](https://matrix.org/docs/spec/client_server/r0.6.1#key-management-api) with the exception of `/keys/changes` which is handled by Sync API. This component is designed to shard by user ID.
+
+Keys are uploaded and stored in this component, and key changes are emitted to a Kafka topic for downstream components such as Sync API.
+
+### Internal APIs
+- `PerformUploadKeys` stores identity keys and one-time public keys for given user(s).
+- `PerformClaimKeys` acquires one-time public keys for given user(s). This may involve outbound federation calls.
+- `QueryKeys` returns identity keys for given user(s). This may involve outbound federation calls. This component may then cache federated identity keys to avoid repeatedly hitting remote servers.
+- A topic which emits identity keys every time there is a change (addition or deletion).
+
+### Endpoint mappings
+- Client API maps `/keys/upload` to `PerformUploadKeys`.
+- Client API maps `/keys/query` to `QueryKeys`.
+- Client API maps `/keys/claim` to `PerformClaimKeys`.
+- Federation API maps `/user/keys/query` to `QueryKeys`.
+- Federation API maps `/user/keys/claim` to `PerformClaimKeys`.
+- Sync API maps `/keys/changes` to consuming from the Kafka topic.
diff --git a/keyserver/api/api.go b/keyserver/api/api.go
new file mode 100644
index 00000000..d8b866f3
--- /dev/null
+++ b/keyserver/api/api.go
@@ -0,0 +1,49 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package api
+
+import "context"
+
+type KeyInternalAPI interface {
+	PerformUploadKeys(ctx context.Context, req *PerformUploadKeysRequest, res *PerformUploadKeysResponse)
+	PerformClaimKeys(ctx context.Context, req *PerformClaimKeysRequest, res *PerformClaimKeysResponse)
+	QueryKeys(ctx context.Context, req *QueryKeysRequest, res *QueryKeysResponse)
+}
+
+// KeyError is returned if there was a problem performing/querying the server
+type KeyError struct {
+	Error string
+}
+
+type PerformUploadKeysRequest struct {
+}
+
+type PerformUploadKeysResponse struct {
+	Error *KeyError
+}
+
+type PerformClaimKeysRequest struct {
+}
+
+type PerformClaimKeysResponse struct {
+	Error *KeyError
+}
+
+type QueryKeysRequest struct {
+}
+
+type QueryKeysResponse struct {
+	Error *KeyError
+}
diff --git a/keyserver/internal/internal.go b/keyserver/internal/internal.go
new file mode 100644
index 00000000..40883cdd
--- /dev/null
+++ b/keyserver/internal/internal.go
@@ -0,0 +1,19 @@
+package internal
+
+import (
+	"context"
+
+	"github.com/matrix-org/dendrite/keyserver/api"
+)
+
+type KeyInternalAPI struct{}
+
+func (a *KeyInternalAPI) PerformUploadKeys(ctx context.Context, req *api.PerformUploadKeysRequest, res *api.PerformUploadKeysResponse) {
+
+}
+func (a *KeyInternalAPI) PerformClaimKeys(ctx context.Context, req *api.PerformClaimKeysRequest, res *api.PerformClaimKeysResponse) {
+
+}
+func (a *KeyInternalAPI) QueryKeys(ctx context.Context, req *api.QueryKeysRequest, res *api.QueryKeysResponse) {
+
+}
diff --git a/keyserver/inthttp/client.go b/keyserver/inthttp/client.go
new file mode 100644
index 00000000..f2d00c70
--- /dev/null
+++ b/keyserver/inthttp/client.go
@@ -0,0 +1,103 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package inthttp
+
+import (
+	"context"
+	"errors"
+	"net/http"
+
+	"github.com/matrix-org/dendrite/internal/httputil"
+	"github.com/matrix-org/dendrite/keyserver/api"
+	"github.com/opentracing/opentracing-go"
+)
+
+// HTTP paths for the internal HTTP APIs
+const (
+	PerformUploadKeysPath = "/keyserver/performUploadKeys"
+	PerformClaimKeysPath  = "/keyserver/performClaimKeys"
+	QueryKeysPath         = "/keyserver/queryKeys"
+)
+
+// NewKeyServerClient creates a KeyInternalAPI implemented by talking to a HTTP POST API.
+// If httpClient is nil an error is returned
+func NewKeyServerClient(
+	apiURL string,
+	httpClient *http.Client,
+) (api.KeyInternalAPI, error) {
+	if httpClient == nil {
+		return nil, errors.New("NewKeyServerClient: httpClient is <nil>")
+	}
+	return &httpKeyInternalAPI{
+		apiURL:     apiURL,
+		httpClient: httpClient,
+	}, nil
+}
+
+type httpKeyInternalAPI struct {
+	apiURL     string
+	httpClient *http.Client
+}
+
+func (h *httpKeyInternalAPI) PerformClaimKeys(
+	ctx context.Context,
+	request *api.PerformClaimKeysRequest,
+	response *api.PerformClaimKeysResponse,
+) {
+	span, ctx := opentracing.StartSpanFromContext(ctx, "PerformClaimKeys")
+	defer span.Finish()
+
+	apiURL := h.apiURL + PerformClaimKeysPath
+	err := httputil.PostJSON(ctx, span, h.httpClient, apiURL, request, response)
+	if err != nil {
+		response.Error = &api.KeyError{
+			Error: err.Error(),
+		}
+	}
+}
+
+func (h *httpKeyInternalAPI) PerformUploadKeys(
+	ctx context.Context,
+	request *api.PerformUploadKeysRequest,
+	response *api.PerformUploadKeysResponse,
+) {
+	span, ctx := opentracing.StartSpanFromContext(ctx, "PerformUploadKeys")
+	defer span.Finish()
+
+	apiURL := h.apiURL + PerformUploadKeysPath
+	err := httputil.PostJSON(ctx, span, h.httpClient, apiURL, request, response)
+	if err != nil {
+		response.Error = &api.KeyError{
+			Error: err.Error(),
+		}
+	}
+}
+
+func (h *httpKeyInternalAPI) QueryKeys(
+	ctx context.Context,
+	request *api.QueryKeysRequest,
+	response *api.QueryKeysResponse,
+) {
+	span, ctx := opentracing.StartSpanFromContext(ctx, "QueryKeys")
+	defer span.Finish()
+
+	apiURL := h.apiURL + QueryKeysPath
+	err := httputil.PostJSON(ctx, span, h.httpClient, apiURL, request, response)
+	if err != nil {
+		response.Error = &api.KeyError{
+			Error: err.Error(),
+		}
+	}
+}
diff --git a/keyserver/inthttp/server.go b/keyserver/inthttp/server.go
new file mode 100644
index 00000000..ec78b613
--- /dev/null
+++ b/keyserver/inthttp/server.go
@@ -0,0 +1,61 @@
+// Copyright 2020 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package inthttp
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/gorilla/mux"
+	"github.com/matrix-org/dendrite/internal/httputil"
+	"github.com/matrix-org/dendrite/keyserver/api"
+	"github.com/matrix-org/util"
+)
+
+func AddRoutes(internalAPIMux *mux.Router, s api.KeyInternalAPI) {
+	internalAPIMux.Handle(PerformClaimKeysPath,
+		httputil.MakeInternalAPI("performClaimKeys", func(req *http.Request) util.JSONResponse {
+			request := api.PerformClaimKeysRequest{}
+			response := api.PerformClaimKeysResponse{}
+			if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
+				return util.MessageResponse(http.StatusBadRequest, err.Error())
+			}
+			s.PerformClaimKeys(req.Context(), &request, &response)
+			return util.JSONResponse{Code: http.StatusOK, JSON: &response}
+		}),
+	)
+	internalAPIMux.Handle(PerformUploadKeysPath,
+		httputil.MakeInternalAPI("performUploadKeys", func(req *http.Request) util.JSONResponse {
+			request := api.PerformUploadKeysRequest{}
+			response := api.PerformUploadKeysResponse{}
+			if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
+				return util.MessageResponse(http.StatusBadRequest, err.Error())
+			}
+			s.PerformUploadKeys(req.Context(), &request, &response)
+			return util.JSONResponse{Code: http.StatusOK, JSON: &response}
+		}),
+	)
+	internalAPIMux.Handle(QueryKeysPath,
+		httputil.MakeInternalAPI("queryKeys", func(req *http.Request) util.JSONResponse {
+			request := api.QueryKeysRequest{}
+			response := api.QueryKeysResponse{}
+			if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
+				return util.MessageResponse(http.StatusBadRequest, err.Error())
+			}
+			s.QueryKeys(req.Context(), &request, &response)
+			return util.JSONResponse{Code: http.StatusOK, JSON: &response}
+		}),
+	)
+}
diff --git a/keyserver/keyserver.go b/keyserver/keyserver.go
index bedc4dfb..3bb0e462 100644
--- a/keyserver/keyserver.go
+++ b/keyserver/keyserver.go
@@ -16,14 +16,19 @@ package keyserver
 
 import (
 	"github.com/gorilla/mux"
-	"github.com/matrix-org/dendrite/internal/config"
-	"github.com/matrix-org/dendrite/keyserver/routing"
-	userapi "github.com/matrix-org/dendrite/userapi/api"
+	"github.com/matrix-org/dendrite/keyserver/api"
+	"github.com/matrix-org/dendrite/keyserver/internal"
+	"github.com/matrix-org/dendrite/keyserver/inthttp"
 )
 
-// AddPublicRoutes registers HTTP handlers for CS API calls
-func AddPublicRoutes(
-	router *mux.Router, cfg *config.Dendrite, userAPI userapi.UserInternalAPI,
-) {
-	routing.Setup(router, cfg, userAPI)
+// AddInternalRoutes registers HTTP handlers for the internal API. Invokes functions
+// on the given input API.
+func AddInternalRoutes(router *mux.Router, intAPI api.KeyInternalAPI) {
+	inthttp.AddRoutes(router, intAPI)
+}
+
+// NewInternalAPI returns a concerete implementation of the internal API. Callers
+// can call functions directly on the returned API or via an HTTP interface using AddInternalRoutes.
+func NewInternalAPI() api.KeyInternalAPI {
+	return &internal.KeyInternalAPI{}
 }
diff --git a/keyserver/routing/keys.go b/keyserver/routing/keys.go
deleted file mode 100644
index a279a747..00000000
--- a/keyserver/routing/keys.go
+++ /dev/null
@@ -1,33 +0,0 @@
-// Copyright 2020 The Matrix.org Foundation C.I.C.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package routing
-
-import (
-	"net/http"
-
-	"github.com/matrix-org/util"
-)
-
-func QueryKeys(
-	req *http.Request,
-) util.JSONResponse {
-	return util.JSONResponse{
-		Code: http.StatusOK,
-		JSON: map[string]interface{}{
-			"failures":    map[string]interface{}{},
-			"device_keys": map[string]interface{}{},
-		},
-	}
-}
diff --git a/keyserver/routing/routing.go b/keyserver/routing/routing.go
deleted file mode 100644
index dba43528..00000000
--- a/keyserver/routing/routing.go
+++ /dev/null
@@ -1,54 +0,0 @@
-// Copyright 2020 The Matrix.org Foundation C.I.C.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package routing
-
-import (
-	"net/http"
-
-	"github.com/gorilla/mux"
-	"github.com/matrix-org/dendrite/internal/config"
-	"github.com/matrix-org/dendrite/internal/httputil"
-	userapi "github.com/matrix-org/dendrite/userapi/api"
-	"github.com/matrix-org/util"
-)
-
-const pathPrefixR0 = "/client/r0"
-
-// Setup registers HTTP handlers with the given ServeMux. It also supplies the given http.Client
-// to clients which need to make outbound HTTP requests.
-//
-// Due to Setup being used to call many other functions, a gocyclo nolint is
-// applied:
-// nolint: gocyclo
-func Setup(
-	publicAPIMux *mux.Router, cfg *config.Dendrite, userAPI userapi.UserInternalAPI,
-) {
-	r0mux := publicAPIMux.PathPrefix(pathPrefixR0).Subrouter()
-
-	r0mux.Handle("/keys/query",
-		httputil.MakeAuthAPI("queryKeys", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			return QueryKeys(req)
-		}),
-	).Methods(http.MethodPost, http.MethodOptions)
-
-	r0mux.Handle("/keys/upload/{keyID}",
-		httputil.MakeAuthAPI("keys_upload", userAPI, func(req *http.Request, device *userapi.Device) util.JSONResponse {
-			return util.JSONResponse{
-				Code: 200,
-				JSON: map[string]interface{}{},
-			}
-		}),
-	).Methods(http.MethodPost, http.MethodOptions)
-}