caddyfile.go

package httpcache

import (
	"encoding/json"
	"fmt"
	"strconv"
	"strings"
	"time"

	"github.com/caddyserver/caddy/v2"
	"github.com/caddyserver/caddy/v2/caddyconfig"
	"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
	"github.com/caddyserver/caddy/v2/caddyconfig/httpcaddyfile"
	"github.com/caddyserver/caddy/v2/modules/caddyhttp"
)

// CacheType is the type of cache which means the backend for storing
// cache content.
type CacheType string

const (
	file     CacheType = "file"
	redis    CacheType = "redis"
	inMemory CacheType = "in_memory"
)

// BYTE represents the num of byte
// 1MB = 2^10 BYTE
// 1GB = 2^10 MB
const (
	BYTE = 1 << (iota * 10)
	KB
	MB
	GB
)

var (
	defaultStatusHeader           = "X-Cache-Status"
	defaultLockTimeout            = time.Duration(5) * time.Minute
	defaultMaxAge                 = time.Duration(5) * time.Minute
	defaultPath                   = "/tmp/caddy_cache"
	defaultMatchMethods           = []string{"GET", "HEAD"}
	defaultCacheType              = file
	defaultcacheBucketsNum        = 256
	defaultCacheMaxMemorySize     = GB // default is 1 GB
	defaultRedisConnectionSetting = "localhost:6379 0"
	defaultStaleMaxAge            = time.Duration(0)
	defaultCacheKeyTemplate       = "{http.request.method} {http.request.host}{http.request.uri.path}?{http.request.uri.query}"
	// Note: prevent character space in the key
	// the key is refereced from github.com/caddyserver/caddy/v2/modules/caddyhttp.addHTTPVarsToReplacer
)

const (
	keyStatusHeader           = "status_header"
	keyLockTimeout            = "lock_timeout"
	keyDefaultMaxAge          = "default_max_age"
	keyPath                   = "path"
	keyMatchHeader            = "match_header"
	keyMatchPath              = "match_path"
	keyMatchMethod            = "match_methods"
	keyCacheKey               = "cache_key"
	keyCacheBucketsNum        = "cache_bucket_num"
	keyCacheMaxMemorySize     = "cache_max_memory_size"
	keyCacheType              = "cache_type"
	keyRedisConnectionSetting = "redis_connection_setting"
	// format: addr db password or addr db or addr
	// ex.
	// localhost:6789 0 => connect without password. only index and host:port provided
	// the following are keys for extensions
	keyDistributed = "distributed"
	keyInfluxLog   = "influxlog"
	keyStaleMaxAge = "stale_max_age"
)

func init() {
	httpcaddyfile.RegisterHandlerDirective("http_cache", parseCaddyfile)
}

// Config is the configuration for cache process
type Config struct {
	Type                   CacheType                `json:"type,omitempty"`
	StatusHeader           string                   `json:"status_header,omitempty"`
	DefaultMaxAge          time.Duration            `json:"default_max_age,omitempty"`
	LockTimeout            time.Duration            `json:"lock_timeout,omitempty"`
	RuleMatchersRaws       []RuleMatcherRawWithType `json:"rule_matcher_raws,omitempty"`
	RuleMatchers           []RuleMatcher            `json:"-"`
	MatchMethods           []string                 `json:"match_methods,omitempty"`
	CacheBucketsNum        int                      `json:"cache_buckets_num,omitempty"`
	CacheMaxMemorySize     int                      `json:"cache_max_memory_size,omitempty"`
	Path                   string                   `json:"path,omitempty"`
	CacheKeyTemplate       string                   `json:"cache_key_template,omitempty"`
	RedisConnectionSetting string                   `json:"redis_connection_setting,omitempty"`
	StaleMaxAge            time.Duration            `json:"stale_max_age,omitempty"`
}

func getDefaultConfig() *Config {
	return &Config{
		StatusHeader:           defaultStatusHeader,
		DefaultMaxAge:          defaultMaxAge,
		LockTimeout:            defaultLockTimeout,
		RuleMatchersRaws:       []RuleMatcherRawWithType{},
		RuleMatchers:           []RuleMatcher{},
		MatchMethods:           defaultMatchMethods,
		CacheBucketsNum:        defaultcacheBucketsNum,
		CacheMaxMemorySize:     defaultCacheMaxMemorySize,
		Path:                   defaultPath,
		Type:                   defaultCacheType,
		CacheKeyTemplate:       defaultCacheKeyTemplate,
		RedisConnectionSetting: defaultRedisConnectionSetting,
		StaleMaxAge:            defaultStaleMaxAge,
	}
}

func parseCaddyfile(h httpcaddyfile.Helper) (caddyhttp.MiddlewareHandler, error) {
	// call Handler UnmarshalCaddyfile
	hr := new(Handler)
	err := hr.UnmarshalCaddyfile(h.Dispenser)
	if err != nil {
		return nil, err
	}

	return hr, nil
}

// UnmarshalCaddyfile sets up the handler from Caddyfile
//
//	:4000 {
//	    reverse_proxy yourserver:5000
//	    http_cache {
//	        match_path /assets
//	        match_header Content-Type image/jpg image/png
//	        status_header X-Cache-Status
//	        default_max_age 15m
//	        path /tmp/caddy-cache
//
//	        distributed consul {
//	            service_name
//	            addr
//	        }
//	    }
//	}
func (h *Handler) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
	config := getDefaultConfig()

	for d.Next() {

		for d.NextBlock(0) {
			parameter := d.Val()
			args := d.RemainingArgs()

			switch parameter {
			case keyStatusHeader:
				if len(args) != 1 {
					return d.Err("Invalid usage of status_header in cache config.")
				}
				config.StatusHeader = args[0]

			case keyRedisConnectionSetting:
				if len(args) > 3 {
					return d.Err("Invalid usage of redis_connection_setting in cache config.")
				}
				config.RedisConnectionSetting = strings.Join(args, " ")

			case keyCacheType:
				if len(args) != 1 {
					return d.Err("Invalid usage of cache_type in cache config.")
				}
				config.Type = CacheType(args[0])

			case keyLockTimeout:
				if len(args) != 1 {
					return d.Err("Invalid usage of lock_timeout in cache config")
				}
				duration, err := time.ParseDuration(args[0])
				if err != nil {
					return d.Err(fmt.Sprintf("%s:%s , %s", keyLockTimeout, "invalid duration", parameter))
				}
				config.LockTimeout = duration

			case keyDefaultMaxAge:
				if len(args) != 1 {
					return d.Err("Invalid usage of default_max_age in cache config.")
				}

				duration, err := time.ParseDuration(args[0])
				if err != nil {
					return d.Err(fmt.Sprintf("%s:%s, %s", keyDefaultMaxAge, "Invalid duration ", parameter))
				}
				config.DefaultMaxAge = duration

			case keyPath:
				if len(args) != 1 {
					return d.Err("Invalid usage of path in cache config.")
				}
				config.Path = args[0]

			case keyMatchHeader:
				if len(args) < 2 {
					return d.Err("Invalid usage of match_header in cache config.")
				}

				cacheRule := &HeaderRuleMatcher{Header: args[0], Value: args[1:]}
				data, _ := json.Marshal(cacheRule)

				config.RuleMatchersRaws = append(config.RuleMatchersRaws, RuleMatcherRawWithType{
					Type: MatcherTypeHeader,
					Data: data,
				})

			case keyMatchPath:
				if len(args) != 1 {
					return d.Err("Invalid usage of match_path in cache config.")
				}
				cacheRule := &PathRuleMatcher{Path: args[0]}
				data, _ := json.Marshal(cacheRule)

				config.RuleMatchersRaws = append(config.RuleMatchersRaws, RuleMatcherRawWithType{
					Type: MatcherTypePath,
					Data: data,
				})

			case keyMatchMethod:
				if len(args) < 2 {
					return d.Err("Invalid usage of match_method in cache config.")
				}
				config.MatchMethods = append(config.MatchMethods, args...)

			case keyCacheKey:
				if len(args) != 1 {
					return d.Err(fmt.Sprintf("Invalid usage of %s in cache config.", keyCacheKey))
				}
				config.CacheKeyTemplate = args[0]

			case keyCacheBucketsNum:
				if len(args) != 1 {
					return d.Err(fmt.Sprintf("Invalid usage of %s in cache config.", keyCacheBucketsNum))
				}
				num, err := strconv.Atoi(args[0])
				if err != nil {
					return d.Err(fmt.Sprintf("Invalid usage of %s, %s", keyCacheBucketsNum, err.Error()))
				}
				config.CacheBucketsNum = num
			case keyCacheMaxMemorySize:
				if len(args) != 1 {
					return d.Err(fmt.Sprintf("Invalid usage of %s in cache config.", keyCacheMaxMemorySize))
				}
				num, err := strconv.Atoi(args[0])
				if err != nil {
					return d.Err(fmt.Sprintf("Invalid usage of %s, %s", keyCacheMaxMemorySize, err.Error()))
				}
				config.CacheMaxMemorySize = num
			case keyDistributed:
				if len(args) != 1 {
					return d.Err(fmt.Sprintf("Invalid usage of %s in cache config.", keyDistributed))
				}
				solution := args[0]

				mod, err := caddy.GetModule("distributed." + solution)
				if err != nil {
					return d.Errf("getting distributed module '%s': '%v'", mod, err)
				}

				unm, ok := mod.New().(caddyfile.Unmarshaler)
				if !ok {
					return d.Errf("distributed module '%s' is not a Caddyfile unmarshaler", mod)
				}

				err = unm.UnmarshalCaddyfile(d.NewFromNextSegment())
				if err != nil {
					return err
				}

				h.DistributedRaw = caddyconfig.JSONModuleObject(unm, "distributed", "consul", nil)

			case keyStaleMaxAge:
				if len(args) != 1 {
					return d.Err("Invalid usage of stale_max_age in cache config.")
				}

				duration, err := time.ParseDuration(args[0])
				if err != nil {
					return d.Err(fmt.Sprintf("%s:%s, %s", keyStaleMaxAge, "Invalid duration ", parameter))
				}
				config.StaleMaxAge = duration

			default:
				return d.Err("Unknown cache parameter: " + parameter)
			}
		}
	}

	h.Config = config

	return nil
}

// Interface guards
var (
	_ caddyfile.Unmarshaler = (*Handler)(nil)
)