Golang forward.New函数代码示例

func (s *STSuite) TestRequestLimitReached(c *C) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		w.Write([]byte("hello"))
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd, err := forward.New()
	c.Assert(err, IsNil)

	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	st, err := New(rdr, Logger(utils.NewFileLogger(os.Stdout, utils.INFO)), MaxRequestBodyBytes(4))
	c.Assert(err, IsNil)

	proxy := httptest.NewServer(st)
	defer proxy.Close()

	re, _, err := testutils.Get(proxy.URL, testutils.Body("this request is too long"))
	c.Assert(err, IsNil)
	c.Assert(re.StatusCode, Equals, http.StatusRequestEntityTooLarge)
}

func (s *STSuite) TestNoBody(c *C) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		w.WriteHeader(http.StatusOK)
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd, err := forward.New()
	c.Assert(err, IsNil)

	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	st, err := New(rdr, Logger(utils.NewFileLogger(os.Stdout, utils.INFO)))
	c.Assert(err, IsNil)

	proxy := httptest.NewServer(st)
	defer proxy.Close()

	re, _, err := testutils.Get(proxy.URL)
	c.Assert(err, IsNil)
	c.Assert(re.StatusCode, Equals, http.StatusOK)
}

func (s *STSuite) TestCustomErrorHandler(c *C) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		w.Write([]byte("hello, this response is too large"))
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd, err := forward.New()
	c.Assert(err, IsNil)

	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	errHandler := utils.ErrorHandlerFunc(func(w http.ResponseWriter, req *http.Request, err error) {
		w.WriteHeader(http.StatusTeapot)
		w.Write([]byte(http.StatusText(http.StatusTeapot)))
	})
	st, err := New(rdr, Logger(utils.NewFileLogger(os.Stdout, utils.INFO)), MaxResponseBodyBytes(4), ErrorHandler(errHandler))
	c.Assert(err, IsNil)

	proxy := httptest.NewServer(st)
	defer proxy.Close()

	re, _, err := testutils.Get(proxy.URL)
	c.Assert(err, IsNil)
	c.Assert(re.StatusCode, Equals, http.StatusTeapot)
}

func (s *RRSuite) TestUpsertWeight(c *C) {
	a := testutils.NewResponder("a")
	defer a.Close()

	b := testutils.NewResponder("b")
	defer b.Close()

	fwd, err := forward.New()
	c.Assert(err, IsNil)

	lb, err := New(fwd)
	c.Assert(err, IsNil)

	c.Assert(lb.UpsertServer(testutils.ParseURI(a.URL)), IsNil)
	c.Assert(lb.UpsertServer(testutils.ParseURI(b.URL)), IsNil)

	proxy := httptest.NewServer(lb)
	defer proxy.Close()

	c.Assert(seq(c, proxy.URL, 3), DeepEquals, []string{"a", "b", "a"})

	c.Assert(lb.UpsertServer(testutils.ParseURI(b.URL), Weight(3)), IsNil)

	c.Assert(seq(c, proxy.URL, 4), DeepEquals, []string{"b", "b", "a", "b"})
}

func (s *RRSuite) TestWeighted(c *C) {
	a := testutils.NewResponder("a")
	defer a.Close()

	b := testutils.NewResponder("b")
	defer b.Close()

	fwd, err := forward.New()
	c.Assert(err, IsNil)

	lb, err := New(fwd)
	c.Assert(err, IsNil)

	lb.UpsertServer(testutils.ParseURI(a.URL), Weight(3))
	lb.UpsertServer(testutils.ParseURI(b.URL), Weight(2))

	proxy := httptest.NewServer(lb)
	defer proxy.Close()

	c.Assert(seq(c, proxy.URL, 6), DeepEquals, []string{"a", "a", "b", "a", "b", "a"})

	w, ok := lb.ServerWeight(testutils.ParseURI(a.URL))
	c.Assert(w, Equals, 3)
	c.Assert(ok, Equals, true)

	w, ok = lb.ServerWeight(testutils.ParseURI(b.URL))
	c.Assert(w, Equals, 2)
	c.Assert(ok, Equals, true)

	w, ok = lb.ServerWeight(testutils.ParseURI("http://caramba:4000"))
	c.Assert(w, Equals, -1)
	c.Assert(ok, Equals, false)
}

func (s *RBSuite) TestRebalancerRemoveServer(c *C) {
	a, b := testutils.NewResponder("a"), testutils.NewResponder("b")
	defer a.Close()
	defer b.Close()

	fwd, err := forward.New()
	c.Assert(err, IsNil)

	lb, err := New(fwd)
	c.Assert(err, IsNil)

	rb, err := NewRebalancer(lb)
	c.Assert(err, IsNil)

	rb.UpsertServer(testutils.ParseURI(a.URL))
	rb.UpsertServer(testutils.ParseURI(b.URL))

	proxy := httptest.NewServer(rb)
	defer proxy.Close()

	c.Assert(seq(c, proxy.URL, 3), DeepEquals, []string{"a", "b", "a"})

	c.Assert(rb.RemoveServer(testutils.ParseURI(a.URL)), IsNil)
	c.Assert(seq(c, proxy.URL, 3), DeepEquals, []string{"b", "b", "b"})
}

// Make sure that stream handler preserves TLS settings
func (s *STSuite) TestPreservesTLS(c *C) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		w.WriteHeader(http.StatusOK)
		w.Write([]byte("ok"))
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd, err := forward.New()
	c.Assert(err, IsNil)

	var t *tls.ConnectionState
	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		t = req.TLS
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	st, err := New(rdr, Logger(utils.NewFileLogger(os.Stdout, utils.INFO)))
	c.Assert(err, IsNil)

	proxy := httptest.NewUnstartedServer(st)
	proxy.StartTLS()
	defer proxy.Close()

	re, _, err := testutils.Get(proxy.URL)
	c.Assert(err, IsNil)
	c.Assert(re.StatusCode, Equals, http.StatusOK)

	c.Assert(t, NotNil)
}

func (s *STSuite) TestChunkedEncodingLimitReached(c *C) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		w.Write([]byte("hello"))
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd, err := forward.New()
	c.Assert(err, IsNil)

	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	st, err := New(rdr, Logger(utils.NewFileLogger(os.Stdout, utils.INFO)), MemRequestBodyBytes(4), MaxRequestBodyBytes(8))
	c.Assert(err, IsNil)

	proxy := httptest.NewServer(st)
	defer proxy.Close()

	conn, err := net.Dial("tcp", testutils.ParseURI(proxy.URL).Host)
	c.Assert(err, IsNil)
	fmt.Fprintf(conn, "POST / HTTP/1.0\r\nTransfer-Encoding: chunked\r\n\r\n4\r\ntest\r\n5\r\ntest1\r\n5\r\ntest2\r\n0\r\n\r\n")
	status, err := bufio.NewReader(conn).ReadString('\n')

	c.Assert(status, Equals, "HTTP/1.0 413 Request Entity Too Large\r\n")
}

func (s *RBSuite) TestRebalancerLive(c *C) {
	a, b := testutils.NewResponder("a"), testutils.NewResponder("b")
	defer a.Close()
	defer b.Close()

	fwd, err := forward.New()
	c.Assert(err, IsNil)

	lb, err := New(fwd)
	c.Assert(err, IsNil)

	rb, err := NewRebalancer(lb, RebalancerBackoff(time.Millisecond), RebalancerClock(s.clock))
	c.Assert(err, IsNil)

	rb.UpsertServer(testutils.ParseURI(a.URL))
	rb.UpsertServer(testutils.ParseURI(b.URL))
	rb.UpsertServer(testutils.ParseURI("http://localhost:62345"))

	proxy := httptest.NewServer(rb)
	defer proxy.Close()

	for i := 0; i < 1000; i += 1 {
		testutils.Get(proxy.URL)
		if i%10 == 0 {
			s.clock.CurrentTime = s.clock.CurrentTime.Add(rb.backoffDuration + time.Second)
		}
	}

	// load balancer changed weights
	c.Assert(rb.servers[0].curWeight, Equals, FSMMaxWeight)
	c.Assert(rb.servers[1].curWeight, Equals, FSMMaxWeight)
	c.Assert(rb.servers[2].curWeight, Equals, 1)
}

func (s *STSuite) TestFileStreamingResponse(c *C) {
	srv := testutils.NewHandler(func(w http.ResponseWriter, req *http.Request) {
		w.Write([]byte("hello, this response is too large to fit in memory"))
	})
	defer srv.Close()

	// forwarder will proxy the request to whatever destination
	fwd, err := forward.New()
	c.Assert(err, IsNil)

	// this is our redirect to server
	rdr := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
		req.URL = testutils.ParseURI(srv.URL)
		fwd.ServeHTTP(w, req)
	})

	// stream handler will forward requests to redirect
	st, err := New(rdr, Logger(utils.NewFileLogger(os.Stdout, utils.INFO)), MemResponseBodyBytes(4))
	c.Assert(err, IsNil)

	proxy := httptest.NewServer(st)
	defer proxy.Close()

	re, body, err := testutils.Get(proxy.URL)
	c.Assert(err, IsNil)
	c.Assert(re.StatusCode, Equals, http.StatusOK)
	c.Assert(string(body), Equals, "hello, this response is too large to fit in memory")
}

// Test scenario when increaing the weight on good endpoints made it worse
func (s *RBSuite) TestRebalancerCascading(c *C) {
	a, b, d := testutils.NewResponder("a"), testutils.NewResponder("b"), testutils.NewResponder("d")
	defer a.Close()
	defer b.Close()
	defer d.Close()

	fwd, err := forward.New()
	c.Assert(err, IsNil)

	lb, err := New(fwd)
	c.Assert(err, IsNil)

	newMeter := func() (Meter, error) {
		return &testMeter{}, nil
	}
	rb, err := NewRebalancer(lb, RebalancerMeter(newMeter), RebalancerClock(s.clock), RebalancerLogger(s.log))
	c.Assert(err, IsNil)

	rb.UpsertServer(testutils.ParseURI(a.URL))
	rb.UpsertServer(testutils.ParseURI(b.URL))
	rb.UpsertServer(testutils.ParseURI(d.URL))
	rb.servers[0].meter.(*testMeter).rating = 0.3

	proxy := httptest.NewServer(rb)
	defer proxy.Close()

	for i := 0; i < 6; i += 1 {
		testutils.Get(proxy.URL)
		testutils.Get(proxy.URL)
		s.clock.CurrentTime = s.clock.CurrentTime.Add(rb.backoffDuration + time.Second)
	}

	// We have increased the load, and the situation became worse as the other servers started failing
	c.Assert(rb.servers[0].curWeight, Equals, 1)
	c.Assert(rb.servers[1].curWeight, Equals, FSMMaxWeight)
	c.Assert(rb.servers[2].curWeight, Equals, FSMMaxWeight)

	// server a is now recovering, the weights should go back to the original state
	rb.servers[0].meter.(*testMeter).rating = 0.3
	rb.servers[1].meter.(*testMeter).rating = 0.2
	rb.servers[2].meter.(*testMeter).rating = 0.2

	for i := 0; i < 6; i += 1 {
		testutils.Get(proxy.URL)
		testutils.Get(proxy.URL)
		s.clock.CurrentTime = s.clock.CurrentTime.Add(rb.backoffDuration + time.Second)
	}

	// the algo reverted it back
	c.Assert(rb.servers[0].curWeight, Equals, 1)
	c.Assert(rb.servers[1].curWeight, Equals, 1)
	c.Assert(rb.servers[2].curWeight, Equals, 1)
}

// Test scenario when one server goes down after what it recovers
func (s *RBSuite) TestRebalancerRecovery(c *C) {
	a, b := testutils.NewResponder("a"), testutils.NewResponder("b")
	defer a.Close()
	defer b.Close()

	fwd, err := forward.New()
	c.Assert(err, IsNil)

	lb, err := New(fwd)
	c.Assert(err, IsNil)

	newMeter := func() (Meter, error) {
		return &testMeter{}, nil
	}
	rb, err := NewRebalancer(lb, RebalancerMeter(newMeter), RebalancerClock(s.clock), RebalancerLogger(s.log))
	c.Assert(err, IsNil)

	rb.UpsertServer(testutils.ParseURI(a.URL))
	rb.UpsertServer(testutils.ParseURI(b.URL))
	rb.servers[0].meter.(*testMeter).rating = 0.3

	proxy := httptest.NewServer(rb)
	defer proxy.Close()

	for i := 0; i < 6; i += 1 {
		testutils.Get(proxy.URL)
		testutils.Get(proxy.URL)
		s.clock.CurrentTime = s.clock.CurrentTime.Add(rb.backoffDuration + time.Second)
	}

	c.Assert(rb.servers[0].curWeight, Equals, 1)
	c.Assert(rb.servers[1].curWeight, Equals, FSMMaxWeight)

	c.Assert(lb.servers[0].weight, Equals, 1)
	c.Assert(lb.servers[1].weight, Equals, FSMMaxWeight)

	// server a is now recovering, the weights should go back to the original state
	rb.servers[0].meter.(*testMeter).rating = 0

	for i := 0; i < 6; i += 1 {
		testutils.Get(proxy.URL)
		testutils.Get(proxy.URL)
		s.clock.CurrentTime = s.clock.CurrentTime.Add(rb.backoffDuration + time.Second)
	}

	c.Assert(rb.servers[0].curWeight, Equals, 1)
	c.Assert(rb.servers[1].curWeight, Equals, 1)

	// Make sure we have applied the weights to the inner load balancer
	c.Assert(lb.servers[0].weight, Equals, 1)
	c.Assert(lb.servers[1].weight, Equals, 1)
}

func (s *RRSuite) TestNoServers(c *C) {
	fwd, err := forward.New()
	c.Assert(err, IsNil)

	lb, err := New(fwd)
	c.Assert(err, IsNil)

	proxy := httptest.NewServer(lb)
	defer proxy.Close()

	re, _, err := testutils.Get(proxy.URL)
	c.Assert(err, IsNil)
	c.Assert(re.StatusCode, Equals, http.StatusInternalServerError)
}

func new(c *C, p string) (*roundrobin.RoundRobin, *Streamer) {
	logger := utils.NewFileLogger(os.Stdout, utils.INFO)
	// forwarder will proxy the request to whatever destination
	fwd, err := forward.New(forward.Logger(logger))
	c.Assert(err, IsNil)

	// load balancer will round robin request
	lb, err := roundrobin.New(fwd)
	c.Assert(err, IsNil)

	// stream handler will forward requests to redirect, make sure it uses files
	st, err := New(lb, Logger(logger), Retry(p), MemRequestBodyBytes(1))
	c.Assert(err, IsNil)

	return lb, st
}

// Removing the server resets the state
func (s *RBSuite) TestRebalancerReset(c *C) {
	a, b, d := testutils.NewResponder("a"), testutils.NewResponder("b"), testutils.NewResponder("d")
	defer a.Close()
	defer b.Close()
	defer d.Close()

	fwd, err := forward.New()
	c.Assert(err, IsNil)

	lb, err := New(fwd)
	c.Assert(err, IsNil)

	newMeter := func() (Meter, error) {
		return &testMeter{}, nil
	}
	rb, err := NewRebalancer(lb, RebalancerMeter(newMeter), RebalancerClock(s.clock), RebalancerLogger(s.log))
	c.Assert(err, IsNil)

	rb.UpsertServer(testutils.ParseURI(a.URL))
	rb.UpsertServer(testutils.ParseURI(b.URL))
	rb.UpsertServer(testutils.ParseURI(d.URL))
	rb.servers[0].meter.(*testMeter).rating = 0.3
	rb.servers[1].meter.(*testMeter).rating = 0
	rb.servers[2].meter.(*testMeter).rating = 0

	proxy := httptest.NewServer(rb)
	defer proxy.Close()

	for i := 0; i < 6; i += 1 {
		testutils.Get(proxy.URL)
		testutils.Get(proxy.URL)
		s.clock.CurrentTime = s.clock.CurrentTime.Add(rb.backoffDuration + time.Second)
	}

	// load balancer changed weights
	c.Assert(rb.servers[0].curWeight, Equals, 1)
	c.Assert(rb.servers[1].curWeight, Equals, FSMMaxWeight)
	c.Assert(rb.servers[2].curWeight, Equals, FSMMaxWeight)

	// Removing servers has reset the state
	rb.RemoveServer(testutils.ParseURI(d.URL))

	c.Assert(rb.servers[0].curWeight, Equals, 1)
	c.Assert(rb.servers[1].curWeight, Equals, 1)
}