feat(core) make service on routes optional (transparent proxying)

kong/db/schema/entities/routes.lua

@@ -104,7 +104,7 @@ return {
                        },
                      }, },
     { tags             = typedefs.tags },
-    { service = { type = "foreign", reference = "services", required = true }, },
+    { service = { type = "foreign", reference = "services" }, },
   },
 
   entity_checks = {

kong/router.lua

@@ -7,13 +7,13 @@ local bit           = require "bit"
 local hostname_type = utils.hostname_type
 local re_match      = ngx.re.match
 local re_find       = ngx.re.find
-local null          = ngx.null
 local insert        = table.insert
 local sort          = table.sort
 local upper         = string.upper
 local lower         = string.lower
 local find          = string.find
 local sub           = string.sub
+local tonumber      = tonumber
 local ipairs        = ipairs
 local pairs         = pairs
 local error         = error
@@ -68,6 +68,9 @@ local MATCH_RULES = {
 }
 
 
+local EMPTY_T = {}
+
+
 local match_route
 local reduce
 
@@ -89,18 +92,22 @@ local protocol_subsystem = {
 }
 
 local function marshall_route(r)
-  local route    = r.route          or null
-  local service  = r.service        or null
-  local headers  = r.headers        or null
-  local paths    = route.paths      or null
-  local methods  = route.methods    or null
-  local protocol = service.protocol or null
-  local sources  = route.sources  or null
-  local destinations = route.destinations or null
-  local snis     = route.snis or null
-
-  if not (headers ~= null or methods ~= null or paths ~= null or
-          sources ~= null or destinations ~= null or snis ~= null) then
+  local route        = r.route
+  local service      = r.service
+  local headers      = r.headers
+  local paths        = route.paths
+  local methods      = route.methods
+  local snis         = route.snis
+  local sources      = route.sources
+  local destinations = route.destinations
+
+
+  local protocol
+  if service then
+    protocol = service.protocol
+  end
+
+  if not (headers or methods or paths or snis or sources or destinations) then
     return nil, "could not categorize route"
   end
 
@@ -125,7 +132,7 @@ local function marshall_route(r)
   -- headers
 
 
-  if headers ~= null then
+  if headers then
     if type(headers) ~= "table" then
       return nil, "headers field must be a table"
     end
@@ -174,7 +181,7 @@ local function marshall_route(r)
   -- paths
 
 
-  if paths ~= null then
+  if paths then
     if type(paths) ~= "table" then
       return nil, "paths field must be a table"
     end
@@ -219,7 +226,7 @@ local function marshall_route(r)
   -- methods
 
 
-  if methods ~= null then
+  if methods then
     if type(methods) ~= "table" then
       return nil, "methods field must be a table"
     end
@@ -238,7 +245,7 @@ local function marshall_route(r)
   -- sources
 
 
-  if sources ~= null then
+  if sources then
     if type(sources) ~= "table" then
       return nil, "sources field must be a table"
     end
@@ -271,7 +278,7 @@ local function marshall_route(r)
   -- destinations
 
 
-  if destinations ~= null then
+  if destinations then
     if type(destinations) ~= "table" then
       return nil, "destinations field must be a table"
     end
@@ -304,7 +311,7 @@ local function marshall_route(r)
   -- snis
 
 
-  if snis ~= null then
+  if snis then
     if type(snis) ~= "table" then
       return nil, "snis field must be a table"
     end
@@ -323,25 +330,26 @@ local function marshall_route(r)
   end
 
 
-  if protocol ~= null then
-    route_t.upstream_url_t.scheme = protocol
-  end
+  -- upstream_url parsing
 
 
-  -- upstream_url parsing
+  if protocol then
+    route_t.upstream_url_t.scheme = protocol
+  end
 
+  local s = service or EMPTY_T
 
-  local host = service.host or null
-  if host ~= null then
+  local host = s.host
+  if host then
     route_t.upstream_url_t.host = host
     route_t.upstream_url_t.type = hostname_type(host)
 
   else
     route_t.upstream_url_t.type = hostname_type("")
   end
 
-  local port = service.port or null
-  if port ~= null then
+  local port = s.port
+  if port then
     route_t.upstream_url_t.port = port
 
   else
@@ -354,7 +362,7 @@ local function marshall_route(r)
   end
 
   if route_t.type == "http" then
-    route_t.upstream_url_t.path = service.path or "/"
+    route_t.upstream_url_t.path = s.path or "/"
   end
 
   return route_t
@@ -1127,14 +1135,13 @@ function _M.new(routes)
             local upstream_url_t = matched_route.upstream_url_t
             local matches        = ctx.matches
 
-
             -- Path construction
 
             if matched_route.type == "http" then
               -- if we do not have a path-match, then the postfix is simply the
               -- incoming path, without the initial slash
               local request_postfix = matches.uri_postfix or sub(req_uri, 2, -1)
-              local upstream_base = upstream_url_t.path
+              local upstream_base = upstream_url_t.path or "/"
 
               if matched_route.strip_uri then
                 -- we drop the matched part, replacing it with the upstream path
@@ -1227,11 +1234,24 @@ function _M.new(routes)
       -- debug HTTP request header logic
 
       if ngx.var.http_kong_debug then
-        ngx.header["Kong-Route-Id"]   = match_t.route.id
-        ngx.header["Kong-Service-Id"] = match_t.service.id
+        if match_t.route then
+          if match_t.route.id then
+            ngx.header["Kong-Route-Id"] = match_t.route.id
+          end
 
-        if match_t.service.name then
-          ngx.header["Kong-Service-Name"] = match_t.service.name
+          if match_t.route.name then
+            ngx.header["Kong-Route-Name"] = match_t.route.name
+          end
+        end
+
+        if match_t.service then
+          if match_t.service.id then
+            ngx.header["Kong-Service-Id"] = match_t.service.id
+          end
+
+          if match_t.service.name then
+            ngx.header["Kong-Service-Name"] = match_t.service.name
+          end
         end
       end