fix: the last chunk containing only newlines will cause a delay in event handling (api7#156)

Author: nic-6443

lib/resty/etcd/v3.lua

@@ -709,7 +709,7 @@ local function request_chunk(self, method, path, opts, timeout)
                 body = body .. chunk
             end
 
-            if not utils.is_empty_str(chunk) and str_byte(chunk, -1) == str_byte("\n") then
+            if #chunk > 0 and str_byte(chunk, -1) == str_byte("\n") then
                 break
             end
 

t/v3/key.t

@@ -660,3 +660,76 @@ qr/1:.*"created":true.*
 2:.*"value":"bcd4".*"value":"bcd4a".*
 timeout/
 --- timeout: 5
+
+
+
+=== TEST 15: An event is divided into multiple http chunks and the last chunk contains only the separator (newline)
+--- http_config eval: $::HttpConfig
+--- config
+    location /version {
+        content_by_lua_block {
+            ngx.say('{"etcdserver":"3.4.0","etcdcluster":"3.4.0"}')
+        }
+    }
+
+    location /v3/watch {
+        content_by_lua_block {
+            -- payload get from tcpdump while running TEST 3 and split the event response into two chunks
+
+            ngx.say('{"result":{"header":{"cluster_id":"14841639068965178418","member_id":"10276657743932975437","revision":"271","raft_term":"7"},"created":true}}')
+            ngx.flush()
+            ngx.sleep(0.1)
+
+            -- send event without trailing new line
+            ngx.print('{"result":{"header":{"cluster_id":"14841639068965178418","member_id":"10276657743932975437","revision":"272","raft_term":"7"},"events":[{"kv":{"key":"L3Rlc3Q=","create_revision":"156","mod_revision":"272","version":"44","value":"ImJjZDMi"}}]}}')
+            ngx.flush()
+            -- send trailing new line
+            ngx.print('\n')
+            ngx.flush()
+
+            -- ensure client timeout
+            ngx.sleep(1)
+        }
+    }
+
+    location /t {
+        content_by_lua_block {
+            local etcd, err = require("resty.etcd").new({
+              protocol = "v3",
+              http_host = {
+                "http://127.0.0.1:" .. ngx.var.server_port,
+              },
+            })
+            check_res(etcd, err)
+
+            local cur_time = ngx.now()
+            local body_chunk_fun, err = etcd:watch("/test", {timeout = 0.5})
+            if not body_chunk_fun then
+                ngx.say("failed to watch: ", err)
+            end
+
+            local idx = 0
+            while true do
+                local chunk, err = body_chunk_fun()
+
+                if not chunk then
+                    if err then
+                        ngx.say(err)
+                    end
+                    break
+                end
+
+                idx = idx + 1
+                ngx.say(idx, ": ", require("cjson").encode(chunk.result))
+            end
+        }
+    }
+--- request
+GET /t
+--- no_error_log
+[error]
+--- response_body_like eval
+qr/1:.*"created":true.*
+2:.*"value":"bcd3".*
+timeout/
+--- timeout: 5