ngx.balancer 如何设置重试状态码

[yuqiquan]

想要使用 ngx.balancer 设置在 404 的时候进行重试，ngx.balancer 支持吗

[tzssangglass]

I think you can learn form:

lua-resty-core/t/balancer.t

Lines 179 to 230 in 99603e5

	=== TEST 5: get last peer failure status (404)
	--- skip_nginx: 4: < 1.7.5
	--- http_config
	lua_package_path "$TEST_NGINX_LUA_PACKAGE_PATH";
	proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504 http_403 http_404;
	proxy_next_upstream_tries 10;
	upstream backend {
	server 0.0.0.1;
	balancer_by_lua_block {
	local b = require "ngx.balancer"
	local state, status = b.get_last_failure()
	print("last peer failure: ", state, " ", status)
	if not ngx.ctx.tries then
	ngx.ctx.tries = 0
	end
	if ngx.ctx.tries < 2 then
	local ok, err = b.set_more_tries(1)
	if not ok then
	return error("failed to set more tries: ", err)
	elseif err then
	ngx.log(ngx.WARN, "set more tries: ", err)
	end
	end
	ngx.ctx.tries = ngx.ctx.tries + 1
	assert(b.set_current_peer("127.0.0.1", tonumber(ngx.var.server_port)))
	}
	}
	--- config
	location = /t {
	proxy_pass http://backend/back;
	}
	location = /back {
	return 404;
	}
	--- request
	GET /t
	--- response_body_like: 404 Not Found
	--- error_code: 404
	--- grep_error_log eval: qr{last peer failure: \S+ \S+}
	--- grep_error_log_out
	last peer failure: nil nil
	last peer failure: next 404
	last peer failure: next 404
	--- no_error_log
	[warn]

1. use the get_last_failure to get 404
2. use set_more_tries to set more retry

just an idea.

[yuqiquan]

ngx.balancer的重试机制好像只有在机器故障，或者是超时的时候才进行重试

如果机器是正常的，只是返回的状态码异常，是不会触发重试机制的，这个时候 local state, status = b.get_last_failure() 返回的结果是nil，nil

最关键的是如何触发这个重试机制

[tzssangglass]

最关键的是如何触发这个重试机制

proxy_next_upstream