feat: convert grpc-status-details-bin in header to HTTP response body…

apisix/plugins/grpc-transcode.lua

@@ -72,6 +72,18 @@ local schema = {
                 "disable_hooks",
             }
         },
+        show_status_in_body = {
+            description = "show decoded grpc-status-details-bin in response body",
+            type        = "boolean",
+            default     = false
+        },
+        -- https://github.com/googleapis/googleapis/blob/b7cb84f5d42e6dba0fdcc2d8689313f6a8c9d7b9/
+        -- google/rpc/status.proto#L46
+        status_detail_type = {
+            description = "the message type of the grpc-status-details-bin's details part, "
+                            .. "if not given, the details part will not be decoded",
+            type        = "string",
+        },
     },
     additionalProperties = true,
     required = { "proto_id", "service", "method" },
@@ -143,6 +155,7 @@ function _M.access(conf, ctx)
     end
 
     ctx.proto_obj = proto_obj
+
 end
 
 
@@ -152,24 +165,27 @@ function _M.header_filter(conf, ctx)
     end
 
     ngx.header["Content-Type"] = "application/json"
-    ngx.header["Trailer"] = {"grpc-status", "grpc-message"}
+    ngx.header.content_length = nil
 
     local headers = ngx.resp.get_headers()
+
     if headers["grpc-status"] ~= nil and headers["grpc-status"] ~= "0" then
         local http_status = status_rel[headers["grpc-status"]]
         if http_status ~= nil then
             ngx.status = http_status
         else
             ngx.status = 599
         end
-        return
+    else
+        -- The error response body does not contain grpc-status and grpc-message
+        ngx.header["Trailer"] = {"grpc-status", "grpc-message"}
     end
 
 end
 
 
 function _M.body_filter(conf, ctx)
-    if ngx.status >= 300 then
+    if ngx.status >= 300 and not conf.show_status_in_body then
         return
     end
 
@@ -178,7 +194,8 @@ function _M.body_filter(conf, ctx)
         return
     end
 
-    local err = response(ctx, proto_obj, conf.service, conf.method, conf.pb_option)
+    local err = response(ctx, proto_obj, conf.service, conf.method, conf.pb_option,
+                         conf.show_status_in_body, conf.status_detail_type)
     if err then
         core.log.error("transform response error: ", err)
         return

apisix/plugins/grpc-transcode/proto.lua

@@ -157,6 +157,97 @@ function _M.protos()
 end
 
 
+local grpc_status_proto = [[
+    syntax = "proto3";
+
+    package grpc_status;
+
+    message Any {
+      // A URL/resource name that uniquely identifies the type of the serialized
+      // protocol buffer message. This string must contain at least
+      // one "/" character. The last segment of the URL's path must represent
+      // the fully qualified name of the type (as in
+      // `path/google.protobuf.Duration`). The name should be in a canonical form
+      // (e.g., leading "." is not accepted).
+      //
+      // In practice, teams usually precompile into the binary all types that they
+      // expect it to use in the context of Any. However, for URLs which use the
+      // scheme `http`, `https`, or no scheme, one can optionally set up a type
+      // server that maps type URLs to message definitions as follows:
+      //
+      // * If no scheme is provided, `https` is assumed.
+      // * An HTTP GET on the URL must yield a [google.protobuf.Type][]
+      //   value in binary format, or produce an error.
+      // * Applications are allowed to cache lookup results based on the
+      //   URL, or have them precompiled into a binary to avoid any
+      //   lookup. Therefore, binary compatibility needs to be preserved
+      //   on changes to types. (Use versioned type names to manage
+      //   breaking changes.)
+      //
+      // Note: this functionality is not currently available in the official
+      // protobuf release, and it is not used for type URLs beginning with
+      // type.googleapis.com.
+      //
+      // Schemes other than `http`, `https` (or the empty scheme) might be
+      // used with implementation specific semantics.
+      //
+      string type_url = 1;
+
+      // Must be a valid serialized protocol buffer of the above specified type.
+      bytes value = 2;
+    }
+
+    // The `Status` type defines a logical error model that is suitable for
+    // different programming environments, including REST APIs and RPC APIs. It is
+    // used by [gRPC](https://github.com/grpc). Each `Status` message contains
+    // three pieces of data: error code, error message, and error details.
+    //
+    // You can find out more about this error model and how to work with it in the
+    // [API Design Guide](https://cloud.google.com/apis/design/errors).
+    message ErrorStatus {
+        // The status code, which should be an enum value of [google.rpc.Code][google.rpc.Code].
+        int32 code = 1;
+
+        // A developer-facing error message, which should be in English. Any
+        // user-facing error message should be localized and sent in the
+        // [google.rpc.Status.details][google.rpc.Status.details] field, or localized by the client.
+        string message = 2;
+
+        // A list of messages that carry the error details.  There is a common set of
+        // message types for APIs to use.
+        repeated Any details = 3;
+    }
+]]
+
+
+local status_pb_state
+local function init_status_pb_state()
+    if not status_pb_state then
+        -- clear current pb state
+        local old_pb_state = pb.state(nil)
+
+        -- initialize protoc compiler
+        protoc.reload()
+        local status_protoc = protoc.new()
+        -- do not use loadfile here, it can not load the proto file when using a relative address
+        -- after luarocks install apisix
+        local ok, err = status_protoc:load(grpc_status_proto, "grpc_status.proto")
+        if not ok then
+            status_protoc:reset()
+            pb.state(old_pb_state)
+            return "failed to load grpc status protocol: " .. err
+        end
+
+        status_pb_state = pb.state(old_pb_state)
+    end
+end
+
+
+function _M.fetch_status_pb_state()
+    return status_pb_state
+end
+
+
 function _M.init()
     local err
     protos, err = core.config.new("/protos", {
@@ -168,6 +259,15 @@ function _M.init()
                        err)
         return
     end
+
+    if not status_pb_state then
+        err = init_status_pb_state()
+        if err then
+            core.log.error("failed to init grpc status proto: ",
+                            err)
+            return
+        end
+    end
 end
 
 

apisix/plugins/grpc-transcode/response.lua

@@ -14,18 +14,94 @@
 -- See the License for the specific language governing permissions and
 -- limitations under the License.
 --
-local util   = require("apisix.plugins.grpc-transcode.util")
+local util        = require("apisix.plugins.grpc-transcode.util")
+local grpc_proto  = require("apisix.plugins.grpc-transcode.proto")
 local core   = require("apisix.core")
 local pb     = require("pb")
 local ngx    = ngx
 local string = string
+local ngx_decode_base64 = ngx.decode_base64
+local ipairs = ipairs
+local pcall  = pcall
 
-return function(ctx, proto, service, method, pb_option)
+
+local function handle_error_response(status_detail_type)
+    local err_msg
+
+    local grpc_status = ngx.header["grpc-status-details-bin"]
+    if grpc_status then
+        grpc_status = ngx_decode_base64(grpc_status)
+        if grpc_status == nil then
+            err_msg = "grpc-status-details-bin is not base64 format"
+            ngx.arg[1] = err_msg
+            return err_msg
+        end
+
+        local status_pb_state = grpc_proto.fetch_status_pb_state()
+        local old_pb_state = pb.state(status_pb_state)
+
+        local ok, decoded_grpc_status = pcall(pb.decode, "grpc_status.ErrorStatus", grpc_status)
+        pb.state(old_pb_state)
+        if not ok then
+            err_msg = "failed to call pb.decode to decode grpc-status-details-bin"
+            ngx.arg[1] = err_msg
+            return err_msg .. ", err: " .. decoded_grpc_status
+        end
+
+        if not decoded_grpc_status then
+            err_msg = "failed to decode grpc-status-details-bin"
+            ngx.arg[1] = err_msg
+            return err_msg
+        end
+
+        local details = decoded_grpc_status.details
+        if status_detail_type and details then
+            local decoded_details = {}
+            for _, detail in ipairs(details) do
+                local ok, err_or_value = pcall(pb.decode, status_detail_type, detail.value)
+                if not ok then
+                    err_msg = "failed to call pb.decode to decode details in "
+                           .. "grpc-status-details-bin"
+                    ngx.arg[1] = err_msg
+                    return err_msg .. ", err: " .. err_or_value
+                end
+
+                if not err_or_value then
+                    err_msg = "failed to decode details in grpc-status-details-bin"
+                    ngx.arg[1] = err_msg
+                    return err_msg
+                end
+
+                core.table.insert(decoded_details, err_or_value)
+            end
+
+            decoded_grpc_status.details = decoded_details
+        end
+
+        local resp_body = {error = decoded_grpc_status}
+        local response, err = core.json.encode(resp_body)
+        if not response then
+            err_msg = "failed to json_encode response body"
+            ngx.arg[1] = err_msg
+            return err_msg .. ", error: " .. err
+        end
+
+        ngx.arg[1] = response
+    end
+end
+
+
+return function(ctx, proto, service, method, pb_option, show_status_in_body, status_detail_type)
     local buffer = core.response.hold_body_chunk(ctx)
     if not buffer then
         return nil
     end
 
+    -- handle error response after the last response chunk
+    if ngx.status >= 300 and show_status_in_body then
+        return handle_error_response(status_detail_type)
+    end
+
     -- when body has already been read by other plugin
     -- the buffer is an empty string
     if buffer == "" and ctx.resp_body then
@@ -44,17 +120,19 @@ return function(ctx, proto, service, method, pb_option)
 
     util.set_options(proto, pb_option)
 
+    local err_msg
     local decoded = pb.decode(m.output_type, buffer)
     if not decoded then
-        ngx.arg[1] = "failed to decode response data by protobuf"
-        return "failed to decode response data by protobuf"
+        err_msg = "failed to decode response data by protobuf"
+        ngx.arg[1] = err_msg
+        return err_msg
     end
 
     local response, err = core.json.encode(decoded)
     if not response then
-        core.log.error("failed to call json_encode data: ", err)
-        response = "failed to json_encode response body"
-        return response
+        err_msg = "failed to json_encode response body"
+        ngx.arg[1] = err_msg
+        return err_msg .. ", err: " .. err
     end
 
     ngx.arg[1] = response