feat: use custom extip server

CHANGELOG.md

@@ -1,3 +1,9 @@
+<a name="v0.2.0"></a>
+## [v0.2.0] - 2023-03-03
+### Features
+- now has the option to use a custom [extip server](https://github.com/hrbrmstr/extip-svr)
+
+
 <a name="v0.1.0"></a>
 ## [v0.1.0] - 2023-02-28
 ### Features

README.md

@@ -2,7 +2,9 @@
 
 Small Golang package/cli that uses special DNS resolvers to return your external IP address.
 
-Presently it uses Google, OpenDNS, and Akamai. If there is a conflict between the resolver answers a message will be delivered on stderr with the conflicting values.
+By default it uses Google, OpenDNS, and Akamai. If there is a conflict between the resolver answers a message will be delivered on stderr with the conflicting values.
+
+Alternatively, you can specify an [extip server](https://github.com/hrbrmstr/extip-svr) to use. See below for how to do that.
 
 ## References
 
@@ -21,7 +23,40 @@ just build # requires https://github.com/casey/just
 go install -ldflags "-s -w" github.com/hrbrmstr/extip@latest
 ```
 
-## TODO
+## Options
+
+```
+Lookup external IP address via DNS.
+
+Defaults to using Akamai, OpenDNS, and Google services.
+You can specify an extip server via the following command line options.
+NOTE: Both server and domain should be specified to override default behavior.
+More info about running an extip server can be found at <https://github.com/hrbrmstr/extip-svr>.
+
+extip 0.2.0
+Usage: extip [--server EXTIP_SERVER] [--domain DOMAIN] [--record-type RECORD_TYPE] [--port PORT]
+
+Options:
+  --server EXTIP_SERVER, -s EXTIP_SERVER
+                         extip-svr IP/FQDN. e.g., ip.rudis.net [env: EXTIP_SERVER]
+  --domain DOMAIN, -d DOMAIN
+                         Domain to use for IP Lookup. e.g., myip.is [env: EXTIP_DOMAIN]
+  --record-type RECORD_TYPE, -r RECORD_TYPE
+                         DNS record type to lookup. One of TXT or A. [default: TXT, env: EXTIP_RECORD_TYPE]
+  --port PORT, -p PORT   Port extip resolver is listening on. [default: 53, env: EXTIP_PORT]
+  --help, -h             display this help and exit
+```
+
+## Usage
+
+Default:
 
-- [ ] Spruce up the CLI to allow folks to choose from the existing list vs use all of them
-- [ ] Allow folks to specify an endpoint and record type so it can be used with the companion server <https://github.com/hrbrmstr/extip-svr>
+```
+extipsvr
+```
+
+Use an extip server:
+
+```
+extip -s ip.rudis.net -d ip.is
+```

go.mod

@@ -3,4 +3,6 @@ module github.com/hrbrmstr/extip
 go 1.19
 
 require (
+	github.com/alexflint/go-arg v1.4.3 // indirect
+	github.com/alexflint/go-scalar v1.1.0 // indirect
 )

go.sum

@@ -0,0 +1,12 @@
+github.com/alexflint/go-arg v1.4.3 h1:9rwwEBpMXfKQKceuZfYcwuc/7YY7tWJbFsgG5cAU/uo=
+github.com/alexflint/go-arg v1.4.3/go.mod h1:3PZ/wp/8HuqRZMUUgu7I+e1qcpUbvmS258mRXkFH4IA=
+github.com/alexflint/go-scalar v1.1.0 h1:aaAouLLzI9TChcPXotr6gUhq+Scr8rl0P9P4PnltbhM=
+github.com/alexflint/go-scalar v1.1.0/go.mod h1:LoFvNMqS1CPrMVltza4LvnGKhaSpc3oyLEBUZVhhS2o=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

justfile

@@ -11,7 +11,7 @@ set shell := ["zsh", "-cu"]
   go build -ldflags "-s -w" -o bin/extip
 
 @run: build
-	./extip
+	./bin/extip
 
 # Be a good citizen
 @fmt:
@@ -25,12 +25,9 @@ set shell := ["zsh", "-cu"]
   GOOS=darwin GOARCH=amd64 go build -ldflags "-s -w" -o bin/extip-darwin-amd64 main.go && cd bin && gzip extip-darwin-amd64
   GOOS=darwin GOARCH=arm64 go build -ldflags "-s -w" -o bin/extip-darwin-arm64 main.go && cd bin && gzip extip-darwin-arm64
 
-# release binaries
-@release:
-  gh workflow run release-binaries.yml   
-
 # Check results against dig. Requires dig.
 @test: build
   [ "$(dig myip.opendns.com @resolver1.opendns.com +short)" = "$(./bin/extip)" ] && echo "Passed OpenDNS test"
   [ "$(dig o-o.myaddr.1.google.com @ns1.google.com TXT +short | tr -d '"')" = "$(./bin/extip)" ] && echo "Passed Google test"
-  [ "$(dig +short TXT whoami.ds.akahelp.net @$(dig +short +answer NS akamai.com | head -1) | grep ns | sed -e 's/[^0-9\.\:]//g')" = "$(./bin/extip)" ] && echo "Passed Akamai test"
+  [ "$(dig +short TXT whoami.ds.akahelp.net @$(dig +short +answer NS akamai.com | head -1) | grep ns | sed -e 's/[^0-9\.\:]//g')" = "$(./bin/extip)" ] && echo "Passed Akamai test"
+  [ "$(dig +short TXT myip.is @ip.rudis.net | tr -d '"')" = "$(./bin/extip)" ] && echo "Passed custom extip server test"

main.go

@@ -7,13 +7,17 @@ import (
 	"net"
 	"os"
 	"regexp"
+	"strconv"
 	"strings"
 	"time"
+
+	"github.com/alexflint/go-arg"
 )
 
 const(
+	version = "0.2.0"
   resolverTimeout = 10000
-  defaultPort = "53"
+  defaultPort = 53
 
   googleResolver = "ns1.google.com"
   openDNSResolver = "resolver1.opendns.com"
@@ -44,13 +48,13 @@ func TrimSuffix(s, suffix string) string {
 }
 
 // Setup a specific resovler to use for DNS lookups
-func UseResolver(resolver string) *net.Resolver {
+func UseResolver(resolver string, port int) *net.Resolver {
 
 	return &net.Resolver{
 		PreferGo: true,
 		Dial: func(ctx context.Context, network, address string) (net.Conn, error) {
 			d := net.Dialer{Timeout: time.Millisecond * time.Duration(resolverTimeout)}
-			return d.DialContext(ctx, network, resolver + ":" + defaultPort)
+			return d.DialContext(ctx, network, resolver + ":" + strconv.Itoa(port))
 		},
 	}
 
@@ -82,7 +86,7 @@ func AkamaiExtIP() ([]string, error) {
 		return []string{""}, err
 	}
 
-	r := UseResolver(akamaiResolver)
+	r := UseResolver(akamaiResolver, defaultPort)
 	txts, err := r.LookupTXT(context.Background(), akamaiHost)
 
 	if (err != nil) {
@@ -98,7 +102,7 @@ func AkamaiExtIP() ([]string, error) {
 // Get our local, external IP via Google's hack
 func GoogleExtIP() ([]string, error) {
 
-	r := UseResolver(googleResolver)
+	r := UseResolver(googleResolver, defaultPort)
 	txts, err := r.LookupTXT(context.Background(), googleHost)
 
 	if (err != nil) {
@@ -112,7 +116,7 @@ func GoogleExtIP() ([]string, error) {
 // Get our local, external IP via OpenDNS's hack
 func OpenDNSExtIP() ([]string, error) {
 
-	r := UseResolver(openDNSResolver)
+	r := UseResolver(openDNSResolver, defaultPort)
 	ips, err := r.LookupHost(context.Background(), openDNSHost)
 
 	if (err != nil) {
@@ -123,10 +127,63 @@ func OpenDNSExtIP() ([]string, error) {
 
 }
 
+// Get our local, external IP via custom extip resolver
+func CustomExtIP(resolver string, host string, rectype string, port int) ([]string, error) {
+
+	r := UseResolver(resolver, port)
+
+	var res [](string)
+	var err error
+
+	if (rectype == "A") {
+	  res, err = r.LookupHost(context.Background(), host)
+	} else {
+		res, err = r.LookupTXT(context.Background(), host)
+	}
+
+	if (err != nil) {
+		res = []string{""}
+	}
+
+	return res, err
+
+}
+
+type args struct {
+	Server string `arg:"-s,--server,env:EXTIP_SERVER" help:"extip-svr IP/FQDN. e.g., ip.rudis.net" placeholder:"EXTIP_SERVER"`
+	Domain string `arg:"-d,--domain,env:EXTIP_DOMAIN" help:"Domain to use for IP Lookup. e.g., myip.is" placeholder:"DOMAIN"`
+	RecordType string `arg:"-r,--record-type,env:EXTIP_RECORD_TYPE" help:"DNS record type to lookup. One of TXT or A." placeholder:"RECORD_TYPE" default:"TXT"`
+	Port int    `arg:"-p,--port,env:EXTIP_PORT" help:"Port extip resolver is listening on." placeholder:"PORT" default:"53"`
+}
+
+func (args) Description() string {
+  return "Lookup external IP address via DNS.\n\nDefaults to using Akamai, OpenDNS, and Google services.\nYou can specify an extip server via the following command line options.\nNOTE: Both server and domain should be specified to override default behavior.\nMore info about running an extip server can be found at <https://github.com/hrbrmstr/extip-svr>.\n"
+}
+
+func (args) Version() string {
+	return "extip " + version
+}
+
 // TODO: Make this a proper CLI with cmdline options since we have 3 services
 func main() {
-	
+
 	l := log.New(os.Stderr, "", 1)
+
+	var args args
+
+  arg.MustParse(&args)
+
+  if args.Server != "" && args.Domain != "" {
+	  custom, cerr := CustomExtIP(args.Server, args.Domain, args.RecordType, args.Port)
+  	if (cerr != nil) {
+	  	l.Println("No DNS resolutions worked.")
+		  os.Exit(3)
+	  } else {
+			fmt.Println(custom[0])
+			os.Exit(0)
+		}
+
+	}
 
 	opendns, oerr := OpenDNSExtIP()
 	google, gerr := GoogleExtIP()