fix(grpc-gateway) map grpc-status to HTTP status code (#25)

Fix #24
Kong · Jun 17, 2021 · b99dd8c · b99dd8c
1 parent b605ada
commit b99dd8c
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Showing 3 changed files with 48 additions and 1 deletion.
diff --git a/kong/plugins/grpc-gateway/handler.lua b/kong/plugins/grpc-gateway/handler.lua
@@ -67,6 +67,28 @@ function grpc_gateway:access(conf)
 end
 
 
+-- https://github.com/googleapis/googleapis/blob/master/google/rpc/code.proto
+local grpc_status_map = {
+   [0] = 200, -- OK
+   [1] = 499, -- CANCELLED
+   [2] = 500, -- UNKNOWN
+   [3] = 400, -- INVALID_ARGUMENT
+   [4] = 504, -- DEADLINE_EXCEEDED
+   [5] = 404, -- NOT_FOUND
+   [6] = 409, -- ALREADY_EXISTS
+   [7] = 403, -- PERMISSION_DENIED
+  [16] = 401, -- UNAUTHENTICATED
+   [8] = 429, -- RESOURCE_EXHAUSTED
+   [9] = 400, -- FAILED_PRECONDITION
+  [10] = 409, -- ABORTED
+  [11] = 400, -- OUT_OF_RANGE
+  [12] = 500, -- UNIMPLEMENTED
+  [13] = 500, -- INTERNAL
+  [14] = 503, -- UNAVAILABLE
+  [15] = 500, -- DATA_LOSS
+}
+
+
 function grpc_gateway:header_filter(conf)
   if kong_request_get_method() == "OPTIONS" then
     return
@@ -76,6 +98,16 @@ function grpc_gateway:header_filter(conf)
   if dec then
     kong_response_set_header("Content-Type", "application/json")
   end
+
+  local grpc_status = tonumber(ngx.header['grpc-status'])
+  if grpc_status then
+    local http_status = grpc_status_map[grpc_status]
+    if not http_status then
+      kong.log.warn("Unable to map grpc-status ", ngx.header['grpc-status'], " to HTTP status code")
+      http_status = 500
+    end
+    ngx.status = http_status
+  end
 end
 
 

diff --git a/spec/01-proxy_spec.lua b/spec/01-proxy_spec.lua
@@ -91,9 +91,17 @@ for _, strategy in helpers.each_strategy() do
 
     test("unknown path", function()
       local res, _ = proxy_client:get("/v1/messages/john_doe/bai")
-      assert.not_equal(200, res.status)
+      assert.equal(400, res.status)
       assert.equal("Bad Request", res.reason)
     end)
 
+    test("transforms grpc-status to HTTP status code", function()
+      local res, _ = proxy_client:get("/v1/unknown/john_doe")
+      -- per ttps://github.com/googleapis/googleapis/blob/master/google/rpc/code.proto
+      -- grpc-status: 12: UNIMPLEMENTED are mapped to http code 500
+      assert.equal(500, res.status)
+      assert.equal('12', res.headers['grpc-status'])
+    end)
+
   end)
 end
diff --git a/spec/fixtures/grpc/helloworld.proto b/spec/fixtures/grpc/helloworld.proto
@@ -17,6 +17,13 @@ service HelloService {
       body: "*"
     }
   };
+
+  // define a gRPC method that's not implemented in grpcbin
+  rpc UnknownMethod(HelloRequest) returns (HelloResponse) {
+    option (google.api.http) = {
+      get: "/v1/unknown/{greeting}"
+    }
+  };
 }
 
 message HelloRequest {