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app/service/main/bns/conf/conf.go

@@ -0,0 +1,229 @@
+package conf
+
+import (
+	"errors"
+	"net/url"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+
+	"github.com/BurntSushi/toml"
+
+	"go-common/library/conf"
+	"go-common/library/log"
+	xtime "go-common/library/time"
+)
+
+// ENV Key
+const (
+	BNSDNSAddr  = "BNS_DNS_HOST"
+	BNSDNSPort  = "BNS_DNS_PORT"
+	BNSHTTPAddr = "BNS_HTTP_ADDR"
+	BNSHTTPPort = "BNS_HTTP_PORT"
+)
+
+// default value
+const (
+	defaultBNSDNSAddr  = "0.0.0.0"
+	defaultBNSDNSPort  = 15353
+	defaultBNSHTTPAddr = "0.0.0.0"
+	defaultBNSHTTPPort = 15380
+)
+
+var defaultConfig Config
+
+func init() {
+	// default dns config
+	defaultDNSConfig := DNSConfig{
+		TTL:             0,
+		AllowStale:      true,
+		UDPAnswerLimit:  3,
+		MaxStale:        xtime.Duration(time.Second * 87600),
+		Domain:          "bili.",
+		RecursorTimeout: xtime.Duration(time.Second),
+	}
+	defaultDNSServer := &DNSServer{
+		Addr:   defaultBNSDNSAddr,
+		Port:   defaultBNSDNSPort,
+		Config: &defaultDNSConfig,
+	}
+
+	// default http config
+	defaultHTTPServer := &HTTPServer{
+		Addr: defaultBNSHTTPAddr,
+		Port: defaultBNSHTTPPort,
+	}
+
+	defaultBackend := &Backend{
+		Backend: "discovery",
+		Config: map[string]interface{}{
+			"url": "http://api.bilibili.co",
+		},
+	}
+
+	defaultConfig = Config{
+		Backend: defaultBackend,
+		HTTP:    defaultHTTPServer,
+		DNS:     defaultDNSServer,
+	}
+}
+
+// LoadConfig from source
+func LoadConfig(source string) (*Config, error) {
+	cfg := defaultConfig
+	var err error
+	if strings.HasPrefix(source, "remote://") {
+		var u *url.URL
+		if u, err = url.Parse(source); err != nil {
+			return nil, err
+		}
+		err = loadRemoteConfig(u.Path, &cfg)
+	} else if source != "" {
+		err = loadLocalConfig(source, &cfg)
+	}
+	if err != nil {
+		return nil, err
+	}
+	overwriteByEnv(&cfg)
+	return &cfg, nil
+}
+
+func loadRemoteConfig(key string, pcfg *Config) error {
+	client, err := conf.New()
+	if err != nil {
+		return err
+	}
+
+	data, ok := client.Value(key)
+	if !ok {
+		return errors.New("load config center error")
+	}
+
+	if _, err = toml.Decode(data, pcfg); err != nil {
+		return errors.New("could not decode config")
+	}
+
+	go func() {
+		for range client.Event() {
+			log.Warn("ignore config reload")
+		}
+	}()
+	return nil
+}
+
+func loadLocalConfig(fpath string, pcfg *Config) error {
+	_, err := toml.DecodeFile(fpath, pcfg)
+	return err
+}
+
+// Config config struct
+type Config struct {
+	Log     *log.Config
+	Backend *Backend
+	HTTP    *HTTPServer
+	DNS     *DNSServer
+}
+
+// overwrite config from env
+func overwriteByEnv(pcfg *Config) {
+	if addr := os.Getenv(BNSDNSAddr); addr != "" {
+		pcfg.DNS.Addr = addr
+	}
+	if portStr := os.Getenv(BNSDNSPort); portStr != "" {
+		if port, err := strconv.Atoi(portStr); err != nil {
+			log.Warn("parse port from env error: %s", err)
+		} else {
+			pcfg.DNS.Port = port
+		}
+	}
+
+	if addr := os.Getenv(BNSHTTPAddr); addr != "" {
+		pcfg.HTTP.Addr = addr
+	}
+	if portStr := os.Getenv(BNSHTTPPort); portStr != "" {
+		if port, err := strconv.Atoi(portStr); err != nil {
+			log.Warn("parse port from env error: %s", err)
+		} else {
+			pcfg.HTTP.Port = port
+		}
+	}
+}
+
+// Backend Config
+type Backend struct {
+	Backend string
+	Config  map[string]interface{}
+}
+
+// HTTPServer http server config
+type HTTPServer struct {
+	Addr string
+	Port int
+}
+
+// DNSServer dns server config
+type DNSServer struct {
+	Addr   string
+	Port   int
+	Config *DNSConfig
+}
+
+// DNSConfig dns config
+type DNSConfig struct {
+	// TTL provides the TTL value for a easyns path query for given path.
+	// The "*" wildcard can be used to set a default to a highlevel path, such as project level path.
+	TTL xtime.Duration `toml:"ttl"`
+
+	// AllowStale is used to enable lookups with stale
+	// data. This gives horizontal read scalability since
+	// any easyns server can service the query instead of
+	// only the leader.
+	AllowStale bool
+
+	// EnableTruncate is used to enable setting the truncate
+	// flag for UDP DNS queries.  This allows unmodified
+	// clients to re-query the easyns server using TCP
+	// when the total number of records exceeds the number
+	// returned by default for UDP.
+	EnableTruncate bool
+
+	// UDPAnswerLimit is used to limit the maximum number of DNS Resource
+	// Records returned in the ANSWER section of a DNS response. This is
+	// not normally useful and will be limited based on the querying
+	// protocol, however systems that implemented §6 Rule 9 in RFC3484
+	// may want to set this to `1` in order to subvert §6 Rule 9 and
+	// re-obtain the effect of randomized resource records (i.e. each
+	// answer contains only one IP, but the IP changes every request).
+	// RFC3484 sorts answers in a deterministic order, which defeats the
+	// purpose of randomized DNS responses.  This RFC has been obsoleted
+	// by RFC6724 and restores the desired behavior of randomized
+	// responses, however a large number of Linux hosts using glibc(3)
+	// implemented §6 Rule 9 and may need this option (e.g. CentOS 5-6,
+	// Debian Squeeze, etc).
+	UDPAnswerLimit int `toml:"udpAnswerLimit"`
+
+	// MaxStale is used to bound how stale of a result is
+	// accepted for a DNS lookup. This can be used with
+	// AllowStale to limit how old of a value is served up.
+	// If the stale result exceeds this, another non-stale
+	// stale read is performed.
+	MaxStale xtime.Duration
+
+	// DisableCompression is used to control whether DNS responses are
+	// compressed. This was turned on by default and this
+	// config was added as an opt-out.
+	DisableCompression bool
+
+	// RecursorTimeout specifies the timeout in seconds
+	// for Easyns agent's internal dns client used for recursion.
+	// This value is used for the connection, read and write timeout.
+	// Default: 2s
+	RecursorTimeout xtime.Duration
+
+	// Managed domain suffix
+	Domain string
+
+	// Upstream recursor dns servers
+	Recursors []string
+}