fix application bug

vendor/github.com/mholt/caddy/caddyhttp/proxy/policy.go

@@ -16,6 +16,7 @@ package proxy
 
 import (
 	"hash/fnv"
+	"log"
 	"math"
 	"math/rand"
 	"net"
@@ -139,7 +140,9 @@ func hostByHashing(pool HostPool, s string) *UpstreamHost {
 // hash calculates a hash based on string s
 func hash(s string) uint32 {
 	h := fnv.New32a()
-	h.Write([]byte(s))
+	if _, err := h.Write([]byte(s)); err != nil {
+		log.Println("[ERROR] failed to write bytes: ", err)
+	}
 	return h.Sum32()
 }
 

vendor/github.com/mholt/caddy/caddyhttp/proxy/proxy.go

@@ -92,8 +92,10 @@ type UpstreamHost struct {
 	// This is an int32 so that we can use atomic operations to do concurrent
 	// reads & writes to this value.  The default value of 0 indicates that it
 	// is healthy and any non-zero value indicates unhealthy.
-	Unhealthy         int32
-	HealthCheckResult atomic.Value
+	Unhealthy                    int32
+	HealthCheckResult            atomic.Value
+	UpstreamHeaderReplacements   headerReplacements
+	DownstreamHeaderReplacements headerReplacements
 }
 
 // Down checks whether the upstream host is down or not.
@@ -220,7 +222,7 @@ func (p Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
 		// set headers for request going upstream
 		if host.UpstreamHeaders != nil {
 			// modify headers for request that will be sent to the upstream host
-			mutateHeadersByRules(outreq.Header, host.UpstreamHeaders, replacer)
+			mutateHeadersByRules(outreq.Header, host.UpstreamHeaders, replacer, host.UpstreamHeaderReplacements)
 			if hostHeaders, ok := outreq.Header["Host"]; ok && len(hostHeaders) > 0 {
 				outreq.Host = hostHeaders[len(hostHeaders)-1]
 			}
@@ -230,7 +232,7 @@ func (p Proxy) ServeHTTP(w http.ResponseWriter, r *http.Request) (int, error) {
 		// headers coming back downstream
 		var downHeaderUpdateFn respUpdateFn
 		if host.DownstreamHeaders != nil {
-			downHeaderUpdateFn = createRespHeaderUpdateFn(host.DownstreamHeaders, replacer)
+			downHeaderUpdateFn = createRespHeaderUpdateFn(host.DownstreamHeaders, replacer, host.DownstreamHeaderReplacements)
 		}
 
 		// Before we retry the request we have to make sure
@@ -376,13 +378,13 @@ func createUpstreamRequest(rw http.ResponseWriter, r *http.Request) (*http.Reque
 	return outreq, cancel
 }
 
-func createRespHeaderUpdateFn(rules http.Header, replacer httpserver.Replacer) respUpdateFn {
+func createRespHeaderUpdateFn(rules http.Header, replacer httpserver.Replacer, replacements headerReplacements) respUpdateFn {
 	return func(resp *http.Response) {
-		mutateHeadersByRules(resp.Header, rules, replacer)
+		mutateHeadersByRules(resp.Header, rules, replacer, replacements)
 	}
 }
 
-func mutateHeadersByRules(headers, rules http.Header, repl httpserver.Replacer) {
+func mutateHeadersByRules(headers, rules http.Header, repl httpserver.Replacer, replacements headerReplacements) {
 	for ruleField, ruleValues := range rules {
 		if strings.HasPrefix(ruleField, "+") {
 			for _, ruleValue := range ruleValues {
@@ -400,6 +402,19 @@ func mutateHeadersByRules(headers, rules http.Header, repl httpserver.Replacer)
 			}
 		}
 	}
+
+	for ruleField, ruleValues := range replacements {
+		for _, ruleValue := range ruleValues {
+			// Replace variables in replacement string
+			replacement := repl.Replace(ruleValue.to)
+			original := headers.Get(ruleField)
+			if len(replacement) > 0 && len(original) > 0 {
+				// Replace matches in original string with replacement string
+				replaced := ruleValue.regexp.ReplaceAllString(original, replacement)
+				headers.Set(ruleField, replaced)
+			}
+		}
+	}
 }
 
 const CustomStatusContextCancelled = 499

vendor/github.com/mholt/caddy/caddyhttp/proxy/reverseproxy.go

@@ -31,6 +31,7 @@ import (
 	"crypto/x509"
 	"fmt"
 	"io"
+	"log"
 	"net"
 	"net/http"
 	"net/url"
@@ -69,7 +70,9 @@ func pooledIoCopy(dst io.Writer, src io.Reader) {
 	// Due to that we extend buf's length to its capacity here and
 	// ensure it's always non-zero.
 	bufCap := cap(buf)
-	io.CopyBuffer(dst, src, buf[0:bufCap:bufCap])
+	if _, err := io.CopyBuffer(dst, src, buf[0:bufCap:bufCap]); err != nil {
+		log.Println("[ERROR] failed to copy buffer: ", err)
+	}
 }
 
 // onExitFlushLoop is a callback set by tests to detect the state of the
@@ -132,12 +135,12 @@ func (rp *ReverseProxy) srvDialerFunc(locator string, timeout time.Duration) fun
 }
 
 func singleJoiningSlash(a, b string) string {
-	aslash := strings.HasSuffix(a, "/")
-	bslash := strings.HasPrefix(b, "/")
+	aSlash := strings.HasSuffix(a, "/")
+	bSlash := strings.HasPrefix(b, "/")
 	switch {
-	case aslash && bslash:
+	case aSlash && bSlash:
 		return a + b[1:]
-	case !aslash && !bslash && b != "":
+	case !aSlash && !bSlash && b != "":
 		return a + "/" + b
 	}
 	return a + b
@@ -275,7 +278,9 @@ func NewSingleHostReverseProxy(target *url.URL, without string, keepalive int, t
 			transport.MaxIdleConnsPerHost = keepalive
 		}
 		if httpserver.HTTP2 {
-			http2.ConfigureTransport(transport)
+			if err := http2.ConfigureTransport(transport); err != nil {
+				log.Println("[ERROR] failed to configure transport to use HTTP/2: ", err)
+			}
 		}
 		rp.Transport = transport
 	} else {
@@ -284,7 +289,9 @@ func NewSingleHostReverseProxy(target *url.URL, without string, keepalive int, t
 			Dial:  rp.dialer.Dial,
 		}
 		if httpserver.HTTP2 {
-			http2.ConfigureTransport(transport)
+			if err := http2.ConfigureTransport(transport); err != nil {
+				log.Println("[ERROR] failed to configure transport to use HTTP/2: ", err)
+			}
 		}
 		rp.Transport = transport
 	}
@@ -394,7 +401,9 @@ func (rp *ReverseProxy) ServeHTTP(rw http.ResponseWriter, outreq *http.Request,
 			if err != nil {
 				return err
 			}
-			outreq.Write(backendConn)
+			if err := outreq.Write(backendConn); err != nil {
+				log.Println("[ERROR] failed to write: ", err)
+			}
 		}
 		defer backendConn.Close()
 
@@ -416,7 +425,9 @@ func (rp *ReverseProxy) ServeHTTP(rw http.ResponseWriter, outreq *http.Request,
 				if err != nil {
 					return err
 				}
-				backendConn.Write(rbuf)
+				if _, err := backendConn.Write(rbuf); err != nil {
+					log.Println("[ERROR] failed to write data to connection: ", err)
+				}
 			}
 		}
 		go func() {
@@ -434,7 +445,7 @@ func (rp *ReverseProxy) ServeHTTP(rw http.ResponseWriter, outreq *http.Request,
 		bodyOpen := true
 		closeBody := func() {
 			if bodyOpen {
-				res.Body.Close()
+				_ = res.Body.Close()
 				bodyOpen = false
 			}
 		}
@@ -681,7 +692,7 @@ func getTransportDialTLS(t *http.Transport) func(network, addr string) (net.Conn
 			errc <- err
 		}()
 		if err := <-errc; err != nil {
-			plainConn.Close()
+			_ = plainConn.Close()
 			return nil, err
 		}
 		if !tlsClientConfig.InsecureSkipVerify {
@@ -690,7 +701,7 @@ func getTransportDialTLS(t *http.Transport) func(network, addr string) (net.Conn
 				hostname = stripPort(addr)
 			}
 			if err := tlsConn.VerifyHostname(hostname); err != nil {
-				plainConn.Close()
+				_ = plainConn.Close()
 				return nil, err
 			}
 		}

vendor/github.com/mholt/caddy/caddyhttp/proxy/upstream.go

@@ -21,10 +21,13 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
+	"log"
 	"net"
 	"net/http"
+	"net/textproto"
 	"net/url"
 	"path"
+	"regexp"
 	"strconv"
 	"strings"
 	"sync"
@@ -65,18 +68,39 @@ type staticUpstream struct {
 		Port          string
 		ContentString string
 	}
-	WithoutPathPrefix  string
-	IgnoredSubPaths    []string
-	insecureSkipVerify bool
-	MaxFails           int32
-	resolver           srvResolver
-	CaCertPool         *x509.CertPool
+	WithoutPathPrefix            string
+	IgnoredSubPaths              []string
+	insecureSkipVerify           bool
+	MaxFails                     int32
+	resolver                     srvResolver
+	CaCertPool                   *x509.CertPool
+	upstreamHeaderReplacements   headerReplacements
+	downstreamHeaderReplacements headerReplacements
 }
 
 type srvResolver interface {
 	LookupSRV(context.Context, string, string, string) (string, []*net.SRV, error)
 }
 
+// headerReplacement stores a compiled regex matcher and a string replacer, for replacement rules
+type headerReplacement struct {
+	regexp *regexp.Regexp
+	to     string
+}
+
+// headerReplacements stores a mapping of canonical MIME header to headerReplacement
+// Implements a subset of http.Header functions, to allow convenient addition and deletion of rules
+type headerReplacements map[string][]headerReplacement
+
+func (h headerReplacements) Add(key string, value headerReplacement) {
+	key = textproto.CanonicalMIMEHeaderKey(key)
+	h[key] = append(h[key], value)
+}
+
+func (h headerReplacements) Del(key string) {
+	delete(h, textproto.CanonicalMIMEHeaderKey(key))
+}
+
 // NewStaticUpstreams parses the configuration input and sets up
 // static upstreams for the proxy middleware. The host string parameter,
 // if not empty, is used for setting the upstream Host header for the
@@ -86,18 +110,20 @@ func NewStaticUpstreams(c caddyfile.Dispenser, host string) ([]Upstream, error)
 	for c.Next() {
 
 		upstream := &staticUpstream{
-			from:              "",
-			stop:              make(chan struct{}),
-			upstreamHeaders:   make(http.Header),
-			downstreamHeaders: make(http.Header),
-			Hosts:             nil,
-			Policy:            &Random{},
-			MaxFails:          1,
-			TryInterval:       250 * time.Millisecond,
-			MaxConns:          0,
-			KeepAlive:         http.DefaultMaxIdleConnsPerHost,
-			Timeout:           30 * time.Second,
-			resolver:          net.DefaultResolver,
+			from:                         "",
+			stop:                         make(chan struct{}),
+			upstreamHeaders:              make(http.Header),
+			downstreamHeaders:            make(http.Header),
+			Hosts:                        nil,
+			Policy:                       &Random{},
+			MaxFails:                     1,
+			TryInterval:                  250 * time.Millisecond,
+			MaxConns:                     0,
+			KeepAlive:                    http.DefaultMaxIdleConnsPerHost,
+			Timeout:                      30 * time.Second,
+			resolver:                     net.DefaultResolver,
+			upstreamHeaderReplacements:   make(headerReplacements),
+			downstreamHeaderReplacements: make(headerReplacements),
 		}
 
 		if !c.Args(&upstream.from) {
@@ -220,9 +246,11 @@ func (u *staticUpstream) NewHost(host string) (*UpstreamHost, error) {
 				return false
 			}
 		}(u),
-		WithoutPathPrefix: u.WithoutPathPrefix,
-		MaxConns:          u.MaxConns,
-		HealthCheckResult: atomic.Value{},
+		WithoutPathPrefix:            u.WithoutPathPrefix,
+		MaxConns:                     u.MaxConns,
+		HealthCheckResult:            atomic.Value{},
+		UpstreamHeaderReplacements:   u.upstreamHeaderReplacements,
+		DownstreamHeaderReplacements: u.downstreamHeaderReplacements,
 	}
 
 	baseURL, err := url.Parse(uh.Name)
@@ -302,6 +330,8 @@ func parseUpstream(u string) ([]string, error) {
 }
 
 func parseBlock(c *caddyfile.Dispenser, u *staticUpstream, hasSrv bool) error {
+	var isUpstream bool
+
 	switch c.Val() {
 	case "policy":
 		if !c.NextArg() {
@@ -431,23 +461,37 @@ func parseBlock(c *caddyfile.Dispenser, u *staticUpstream, hasSrv bool) error {
 		}
 		u.HealthCheck.ContentString = c.Val()
 	case "header_upstream":
-		var header, value string
-		if !c.Args(&header, &value) {
-			// When removing a header, the value can be optional.
-			if !strings.HasPrefix(header, "-") {
-				return c.ArgErr()
-			}
-		}
-		u.upstreamHeaders.Add(header, value)
+		isUpstream = true
+		fallthrough
 	case "header_downstream":
-		var header, value string
-		if !c.Args(&header, &value) {
-			// When removing a header, the value can be optional.
-			if !strings.HasPrefix(header, "-") {
+		var header, value, replaced string
+		if c.Args(&header, &value, &replaced) {
+			// Don't allow - or + in replacements
+			if strings.HasPrefix(header, "-") || strings.HasPrefix(header, "+") {
 				return c.ArgErr()
 			}
+			r, err := regexp.Compile(value)
+			if err != nil {
+				return err
+			}
+			if isUpstream {
+				u.upstreamHeaderReplacements.Add(header, headerReplacement{r, replaced})
+			} else {
+				u.downstreamHeaderReplacements.Add(header, headerReplacement{r, replaced})
+			}
+		} else {
+			if len(value) == 0 {
+				// When removing a header, the value can be optional.
+				if !strings.HasPrefix(header, "-") {
+					return c.ArgErr()
+				}
+			}
+			if isUpstream {
+				u.upstreamHeaders.Add(header, value)
+			} else {
+				u.downstreamHeaders.Add(header, value)
+			}
 		}
-		u.downstreamHeaders.Add(header, value)
 	case "transparent":
 		// Note: X-Forwarded-For header is always being appended for proxy connections
 		// See implementation of createUpstreamRequest in proxy.go
@@ -589,8 +633,10 @@ func (u *staticUpstream) healthCheck() {
 					return true
 				}
 				defer func() {
-					io.Copy(ioutil.Discard, r.Body)
-					r.Body.Close()
+					if _, err := io.Copy(ioutil.Discard, r.Body); err != nil {
+						log.Println("[ERROR] failed to copy: ", err)
+					}
+					_ = r.Body.Close()
 				}()
 				if r.StatusCode < 200 || r.StatusCode >= 400 {
 					return true