ingress-nginx-helm/controllers/nginx/nginx/template.go

/*
Copyright 2015 The Kubernetes Authors All rights reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package nginx

import (
	"bytes"
	"encoding/json"
	"fmt"
	"regexp"
	"strings"
	"text/template"

	"github.com/fatih/structs"
	"github.com/golang/glog"

	"k8s.io/contrib/ingress/controllers/nginx/nginx/config"
)

const (
	slash = "/"
)

var (
	camelRegexp = regexp.MustCompile("[0-9A-Za-z]+")
	tmplPath    = "/etc/nginx/template/nginx.tmpl"

	funcMap = template.FuncMap{
		"empty": func(input interface{}) bool {
			check, ok := input.(string)
			if ok {
				return len(check) == 0
			}

			return true
		},
		"buildLocation":       buildLocation,
		"buildProxyPass":      buildProxyPass,
		"buildRateLimitZones": buildRateLimitZones,
		"buildRateLimit":      buildRateLimit,
	}
)

func (ngx *Manager) loadTemplate() error {
	tmpl, err := template.New("nginx.tmpl").Funcs(funcMap).ParseFiles(tmplPath)
	if err != nil {
		return err
	}
	ngx.template = tmpl
	return nil
}

func (ngx *Manager) writeCfg(cfg config.Configuration, ingressCfg IngressConfig) (bool, error) {
	conf := make(map[string]interface{})
	conf["backlogSize"] = sysctlSomaxconn()
	conf["upstreams"] = ingressCfg.Upstreams
	conf["servers"] = ingressCfg.Servers
	conf["tcpUpstreams"] = ingressCfg.TCPUpstreams
	conf["udpUpstreams"] = ingressCfg.UDPUpstreams
	conf["defResolver"] = ngx.defResolver
	conf["sslDHParam"] = ngx.sslDHParam
	conf["customErrors"] = len(cfg.CustomHTTPErrors) > 0
	conf["cfg"] = fixKeyNames(structs.Map(cfg))

	if glog.V(3) {
		b, err := json.Marshal(conf)
		if err != nil {
			glog.Errorf("unexpected error:", err)
		}
		glog.Infof("NGINX configuration: %v", string(b))
	}

	buffer := new(bytes.Buffer)
	err := ngx.template.Execute(buffer, conf)
	if err != nil {
		glog.V(3).Infof("%v", string(buffer.Bytes()))
		return false, err
	}

	changed, err := ngx.needsReload(buffer)
	if err != nil {
		return false, err
	}

	return changed, nil
}

func fixKeyNames(data map[string]interface{}) map[string]interface{} {
	fixed := make(map[string]interface{})
	for k, v := range data {
		fixed[toCamelCase(k)] = v
	}

	return fixed
}

func toCamelCase(src string) string {
	byteSrc := []byte(src)
	chunks := camelRegexp.FindAll(byteSrc, -1)
	for idx, val := range chunks {
		if idx > 0 {
			chunks[idx] = bytes.Title(val)
		}
	}
	return string(bytes.Join(chunks, nil))
}

// buildLocation produces the location string, if the ingress has redirects
// (specified through the ingress.kubernetes.io/rewrite-to annotation)
func buildLocation(input interface{}) string {
	location, ok := input.(*Location)
	if !ok {
		return slash
	}

	path := location.Path
	if len(location.Redirect.Target) > 0 && location.Redirect.Target != path {
		return fmt.Sprintf("~* %s", path)
	}

	return path
}

// buildProxyPass produces the proxy pass string, if the ingress has redirects
// (specified through the ingress.kubernetes.io/rewrite-to annotation)
// If the annotation ingress.kubernetes.io/add-base-url:"true" is specified it will
// add a base tag in the head of the response from the service
func buildProxyPass(input interface{}) string {
	location, ok := input.(*Location)
	if !ok {
		return ""
	}

	path := location.Path

	proto := "http"
	if location.SecureUpstream {
		proto = "https"
	}
	// defProxyPass returns the default proxy_pass, just the name of the upstream
	defProxyPass := fmt.Sprintf("proxy_pass %s://%s;", proto, location.Upstream.Name)
	// if the path in the ingress rule is equals to the target: no special rewrite
	if path == location.Redirect.Target {
		return defProxyPass
	}

	if path != slash && !strings.HasSuffix(path, slash) {
		path = fmt.Sprintf("%s/", path)
	}

	if len(location.Redirect.Target) > 0 {
		abu := ""
		if location.Redirect.AddBaseURL {
			bPath := location.Redirect.Target
			if !strings.HasSuffix(bPath, slash) {
				bPath = fmt.Sprintf("%s/", bPath)
			}

			abu = fmt.Sprintf(`subs_filter '<head(.*)>' '<head$1><base href="$scheme://$server_name%v">' r;
	subs_filter '<HEAD(.*)>' '<HEAD$1><base href="$scheme://$server_name%v">' r;
	`, bPath, bPath)
		}

		if location.Redirect.Target == slash {
			// special case redirect to /
			// ie /something to /
			return fmt.Sprintf(`
	rewrite %s(.*) /$1 break;
	rewrite %s / break;
	proxy_pass %s://%s;
	%v`, path, location.Path, proto, location.Upstream.Name, abu)
		}

		return fmt.Sprintf(`
	rewrite %s(.*) %s/$1 break;
	proxy_pass %s://%s;
	%v`, path, location.Redirect.Target, proto, location.Upstream.Name, abu)
	}

	// default proxy_pass
	return defProxyPass
}

// buildRateLimitZones produces an array of limit_conn_zone in order to allow
// rate limiting of request. Each Ingress rule could have up to two zones, one
// for connection limit by IP address and other for limiting request per second
func buildRateLimitZones(input interface{}) []string {
	zones := []string{}

	servers, ok := input.([]*Server)
	if !ok {
		return zones
	}

	for _, server := range servers {
		for _, loc := range server.Locations {

			if loc.RateLimit.Connections.Limit > 0 {
				zone := fmt.Sprintf("limit_conn_zone $binary_remote_addr zone=%v:%vm;",
					loc.RateLimit.Connections.Name, loc.RateLimit.Connections.SharedSize)
				zones = append(zones, zone)
			}

			if loc.RateLimit.RPS.Limit > 0 {
				zone := fmt.Sprintf("limit_conn_zone $binary_remote_addr zone=%v:%vm rate=%vr/s;",
					loc.RateLimit.Connections.Name, loc.RateLimit.Connections.SharedSize, loc.RateLimit.Connections.Limit)
				zones = append(zones, zone)
			}
		}
	}

	return zones
}

// buildRateLimit produces an array of limit_req to be used inside the Path of
// Ingress rules. The order: connections by IP first and RPS next.
func buildRateLimit(input interface{}) []string {
	limits := []string{}

	loc, ok := input.(*Location)
	if !ok {
		return limits
	}

	if loc.RateLimit.Connections.Limit > 0 {
		limit := fmt.Sprintf("limit_conn %v %v;",
			loc.RateLimit.Connections.Name, loc.RateLimit.Connections.Limit)
		limits = append(limits, limit)
	}

	if loc.RateLimit.RPS.Limit > 0 {
		limit := fmt.Sprintf("limit_req zone=%v burst=%v nodelay;",
			loc.RateLimit.Connections.Name, loc.RateLimit.Connections.Burst)
		limits = append(limits, limit)
	}

	return limits
}