cmd/resolver: implement command to fetch and print server environment

The "env" command fetch the current server environment and print as
ini format to stdout.

6 files changed, 146 insertions, 14 deletions

diff --git a/_doc/resolver.1.gz b/_doc/resolver.1.gz
index 599ce1d..db15a61 100644
--- a/_doc/resolver.1.gz
+++ b/_doc/resolver.1.gz
diff --git a/_doc/resolver.adoc b/_doc/resolver.adoc
index 9c475d9..46fbc15 100644
--- a/_doc/resolver.adoc
+++ b/_doc/resolver.adoc
@@ -3,7 +3,7 @@
 = RESOLVER(1)
 :doctype: manpage
 :man source: resolver
-:man version: 2018.08.26
+:man version: 2022.04.15
 :man manual: resolver
 
 
@@ -115,6 +115,12 @@ Remove the domain name from rescached caches.
 If the parameter is "all", it will remove all caches.
 --
 
+env::
++
+--
+Fetch the current server environment and print it as JSON format to stdout.
+--
+
 
 == EXIT STATUS
 
@@ -152,7 +158,19 @@ Inspect the rescached's caches on server at http://127.0.0.1:5380,
 
 Search caches that contains "bit" on the domain name,
 
-	$ resolver -server=http://127.0.0.1:5380 caches search bit
+	$ resolver caches search bit
+
+Remove caches that contains domain name "kilabit.info",
+
+	$ resolver caches remove kilabit.info
+
+Remove all caches in the server,
+
+	$ resolver caches remove all
+
+Fetch and print current server environment,
+
+	$ resolver env
 
 
 == AUTHOR
diff --git a/client.go b/client.go
index 289f031..bafb16b 100644
--- a/client.go
+++ b/client.go
@@ -114,10 +114,33 @@ func (cl *Client) CachesSearch(q string) (listMsg []*dns.Message, err error) {
 	if err != nil {
 		return nil, fmt.Errorf("%s: %w", logp, err)
 	}
-
 	if res.Code != http.StatusOK {
 		return nil, fmt.Errorf("%s: %d %s", logp, res.Code, res.Message)
 	}
 
 	return listMsg, nil
 }
+
+// Env get the server environment.
+func (cl *Client) Env() (env *Environment, err error) {
+	var (
+		logp = "Env"
+		res  = libhttp.EndpointResponse{
+			Data: &env,
+		}
+		resb []byte
+	)
+
+	_, resb, err = cl.Get(apiEnvironment, nil, nil)
+	if err != nil {
+		return nil, fmt.Errorf("%s: %w", logp, err)
+	}
+	err = json.Unmarshal(resb, &res)
+	if err != nil {
+		return nil, fmt.Errorf("%s: %w", logp, err)
+	}
+	if res.Code != http.StatusOK {
+		return nil, fmt.Errorf("%s: %d %s", logp, res.Code, res.Message)
+	}
+	return env, nil
+}
diff --git a/cmd/resolver/main.go b/cmd/resolver/main.go
index 90a1686..90fcc68 100644
--- a/cmd/resolver/main.go
+++ b/cmd/resolver/main.go
@@ -16,6 +16,7 @@ import (
 // List of valid commands.
 const (
 	cmdCaches = "caches"
+	cmdEnv    = "env"
 	cmdQuery  = "query"
 
 	subCmdSearch = "search"
@@ -83,6 +84,9 @@ func main() {
 			os.Exit(2)
 		}
 
+	case cmdEnv:
+		rsol.doCmdEnv()
+
 	case cmdQuery:
 		args = args[1:]
 		if len(args) == 0 {
@@ -165,6 +169,11 @@ caches remove <string>
 	Remove the domain name from rescached caches.
 	If the parameter is "all", it will remove all caches.
 
+env
+
+	Fetch the current server environment and print it as JSON format to
+	stdout.
+
 
 ==  Examples
 
@@ -197,5 +206,17 @@ Inspect the rescached's caches on server at http://127.0.0.1:5380,
 
 Search caches that contains "bit" on the domain name,
 
-	$ resolver -server=http://127.0.0.1:5380 caches search bit`)
+	$ resolver caches search bit
+
+Remove caches that contains domain name "kilabit.info",
+
+	$ resolver caches remove kilabit.info
+
+Remove all caches in the server,
+
+	$ resolver caches remove all
+
+Fetch and print current server environment,
+
+	$ resolver env`)
 }
diff --git a/cmd/resolver/resolver.go b/cmd/resolver/resolver.go
index 1985981..b7129cc 100644
--- a/cmd/resolver/resolver.go
+++ b/cmd/resolver/resolver.go
@@ -4,6 +4,7 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
 	"log"
 	"math/rand"
@@ -103,6 +104,30 @@ func (rsol *resolver) doCmdCachesSearch(q string) {
 	printMessages(listMsg)
 }
 
+func (rsol *resolver) doCmdEnv() {
+	var (
+		resc = rsol.newRescachedClient()
+
+		env     *rescached.Environment
+		envJson []byte
+		err     error
+	)
+
+	env, err = resc.Env()
+	if err != nil {
+		log.Printf("resolver: %s: %s", rsol.cmd, err)
+		return
+	}
+
+	envJson, err = json.MarshalIndent(env, "", "  ")
+	if err != nil {
+		log.Printf("resolver: %s: %s", rsol.cmd, err)
+		return
+	}
+
+	fmt.Printf("%s\n", envJson)
+}
+
 func (rsol *resolver) doCmdQuery(args []string) {
 	var (
 		maxAttempts = defAttempts
diff --git a/environment.go b/environment.go
index 43ce214..b8f2729 100644
--- a/environment.go
+++ b/environment.go
@@ -5,6 +5,7 @@ package rescached
 
 import (
 	"fmt"
+	"io"
 	"strconv"
 	"strings"
 
@@ -214,13 +215,21 @@ func (env *Environment) loadResolvConf() (ok bool, err error) {
 	return true, nil
 }
 
-//
-// write the options values back to file.
-//
-func (env *Environment) write(file string) (err error) {
-	in, err := ini.Open(file)
-	if err != nil {
-		return fmt.Errorf("write: %w", err)
+func (env *Environment) save(file string) (in *ini.Ini, err error) {
+	var (
+		logp = "save"
+
+		hb *hostsBlock
+		ns string
+	)
+
+	if len(file) == 0 {
+		in = &ini.Ini{}
+	} else {
+		in, err = ini.Open(file)
+		if err != nil {
+			return nil, fmt.Errorf("%s: %w", logp, err)
+		}
 	}
 
 	in.Set(sectionNameRescached, "", keyFileResolvConf, env.FileResolvConf)
@@ -229,14 +238,14 @@ func (env *Environment) write(file string) (err error) {
 
 	in.UnsetAll(sectionNameRescached, "", keyHostsBlock)
 
-	for _, hb := range env.HostsBlocks {
+	for _, hb = range env.HostsBlocks {
 		if hb.IsEnabled {
 			in.Add(sectionNameRescached, "", keyHostsBlock, hb.URL)
 		}
 	}
 
 	in.UnsetAll(sectionNameDNS, subNameServer, keyParent)
-	for _, ns := range env.NameServers {
+	for _, ns = range env.NameServers {
 		in.Add(sectionNameDNS, subNameServer, keyParent, ns)
 	}
 
@@ -262,5 +271,41 @@ func (env *Environment) write(file string) (err error) {
 	in.Set(sectionNameDNS, subNameServer, keyCachePruneThreshold,
 		fmt.Sprintf("%s", env.ServerOptions.PruneThreshold))
 
-	return in.Save(file)
+	return in, nil
+}
+
+// Write the configuration as ini format to Writer w.
+func (env *Environment) Write(w io.Writer) (err error) {
+	if w == nil {
+		return nil
+	}
+
+	var (
+		logp = "Environment.Write"
+		in   *ini.Ini
+	)
+
+	in, err = env.save(env.fileConfig)
+	if err != nil {
+		return fmt.Errorf("%s: %w", logp, err)
+	}
+
+	return in.Write(w)
+}
+
+//
+// write the options values back to file.
+//
+func (env *Environment) write(file string) (err error) {
+	var (
+		in *ini.Ini
+	)
+	in, err = env.save(file)
+	if err != nil {
+		return err
+	}
+	if len(file) > 0 {
+		return in.Save(file)
+	}
+	return nil
 }