feat: API Handlers

Makefile

@@ -23,7 +23,7 @@ run-cli: build-cli ## Build and Execute the CLI binary after the build step.
 
 .PHONY: run-api
 run-api: build-api ## Build and Execute the API binary after the build step.
-	${API_BIN}
+	${API_BIN} --config config-api-sample.toml
 
 .PHONY: clean
 clean:

cmd/doggo/api/api.go

@@ -1,82 +1,51 @@
 package main
 
 import (
-	"encoding/json"
 	"net/http"
+	"time"
+
+	"github.com/mr-karan/doggo/internal/app"
+	"github.com/mr-karan/doggo/pkg/utils"
+	"github.com/sirupsen/logrus"
 
 	"github.com/go-chi/chi"
-	"github.com/go-chi/chi/middleware"
 	"github.com/knadh/koanf"
-	"github.com/mr-karan/doggo/pkg/utils"
 )
 
 var (
 	logger = utils.InitLogger()
-	k      = koanf.New(".")
+	ko     = koanf.New(".")
+	// Version and date of the build. This is injected at build-time.
+	buildVersion = "unknown"
+	buildDate    = "unknown"
 )
 
-type resp struct {
-	Status  string      `json:"status"`
-	Message string      `json:"message,omitempty"`
-	Data    interface{} `json:"data,omitempty"`
-}
-
 func main() {
+	initConfig()
 
+	// Initialize app.
+	app := app.New(logger, buildVersion)
+
+	// Register handles.
 	r := chi.NewRouter()
+	r.Get("/", wrap(app, handleIndex))
+	r.Get("/ping/", wrap(app, handleHealthCheck))
+	r.Post("/lookup/", wrap(app, handleLookup))
 
-	// Setup middlewares.
-	r.Use(middleware.RequestID)
-	r.Use(middleware.RealIP)
-	r.Use(middleware.Logger)
-	r.Use(middleware.Recoverer)
-
-	r.Get("/", func(w http.ResponseWriter, r *http.Request) {
-		sendSuccessResponse("Welcome to Doggo DNS!", w)
-		return
-	})
-
-	r.Get("/ping/", func(w http.ResponseWriter, r *http.Request) {
-		sendSuccessResponse("PONG", w)
-		return
-	})
-
-	r.Post("/lookup/", func(w http.ResponseWriter, r *http.Request) {
-		return
-	})
-
-	http.ListenAndServe(":3000", r)
-}
-
-// sendResponse sends an HTTP success response.
-func sendResponse(data interface{}, statusText string, status int, w http.ResponseWriter) {
-	w.WriteHeader(status)
-	w.Header().Set("Content-Type", "application/json; charset=utf-8")
-
-	out, err := json.Marshal(resp{Status: statusText, Data: data})
-	if err != nil {
-		sendErrorResponse("Internal Server Error", http.StatusInternalServerError, nil, w)
-		return
+	// HTTP Server.
+	srv := &http.Server{
+		Addr:         ko.String("server.address"),
+		Handler:      r,
+		ReadTimeout:  ko.Duration("server.read_timeout") * time.Millisecond,
+		WriteTimeout: ko.Duration("server.write_timeout") * time.Millisecond,
+		IdleTimeout:  ko.Duration("server.keepalive_timeout") * time.Millisecond,
 	}
 
-	_, _ = w.Write(out)
-}
-
-// sendSuccessResponse sends an HTTP success (200 OK) response.
-func sendSuccessResponse(data interface{}, w http.ResponseWriter) {
-	sendResponse(data, "success", http.StatusOK, w)
-}
-
-// sendErrorResponse sends an HTTP error response.
-func sendErrorResponse(message string, status int, data interface{}, w http.ResponseWriter) {
-	w.Header().Set("Content-Type", "application/json; charset=utf-8")
-	w.WriteHeader(status)
-
-	resp := resp{Status: "error",
-		Message: message,
-		Data:    data}
-
-	out, _ := json.Marshal(resp)
-
-	_, _ = w.Write(out)
+	logger.WithFields(logrus.Fields{
+		"address": srv.Addr,
+	}).Info("starting server")
+
+	if err := srv.ListenAndServe(); err != nil {
+		logger.Fatalf("couldn't start server: %v", err)
+	}
 }

cmd/doggo/api/config.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/knadh/koanf/parsers/toml"
+	"github.com/knadh/koanf/providers/env"
+	"github.com/knadh/koanf/providers/file"
+	"github.com/knadh/koanf/providers/posflag"
+	"github.com/sirupsen/logrus"
+	flag "github.com/spf13/pflag"
+)
+
+// Config is the config given by the user
+type Config struct {
+	HTTPAddr string `koanf:"listen_addr"`
+}
+
+func initConfig() {
+	f := flag.NewFlagSet("api", flag.ContinueOnError)
+	f.Usage = func() {
+		fmt.Println(f.FlagUsages())
+		os.Exit(0)
+	}
+
+	// Register --config flag.
+	f.StringSlice("config", []string{"config.toml"},
+		"Path to one or more TOML config files to load in order")
+
+	// Register --version flag.
+	f.Bool("version", false, "Show build version")
+	f.Parse(os.Args[1:])
+	// Display version.
+	if ok, _ := f.GetBool("version"); ok {
+		fmt.Println(buildVersion, buildDate)
+		os.Exit(0)
+	}
+
+	// Read the config files.
+	cFiles, _ := f.GetStringSlice("config")
+	for _, f := range cFiles {
+		logger.WithFields(logrus.Fields{
+			"file": f,
+		}).Info("reading config")
+		if err := ko.Load(file.Provider(f), toml.Parser()); err != nil {
+			logger.Fatalf("error reading config: %v", err)
+		}
+	}
+	// Load environment variables and merge into the loaded config.
+	if err := ko.Load(env.Provider("DOGGO_API_", ".", func(s string) string {
+		return strings.Replace(strings.ToLower(
+			strings.TrimPrefix(s, "DOGGO_API_")), "__", ".", -1)
+	}), nil); err != nil {
+		logger.Fatalf("error loading env config: %v", err)
+	}
+
+	ko.Load(posflag.Provider(f, ".", ko), nil)
+}

cmd/doggo/api/handlers.go

@@ -0,0 +1,130 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"time"
+
+	"github.com/mr-karan/doggo/internal/app"
+	"github.com/mr-karan/doggo/pkg/models"
+	"github.com/mr-karan/doggo/pkg/resolvers"
+)
+
+type httpResp struct {
+	Status  string      `json:"status"`
+	Message string      `json:"message,omitempty"`
+	Data    interface{} `json:"data,omitempty"`
+}
+
+func handleIndex(w http.ResponseWriter, r *http.Request) {
+	sendResponse(w, http.StatusOK, "Welcome to Doggo API.")
+	return
+}
+
+func handleHealthCheck(w http.ResponseWriter, r *http.Request) {
+	sendResponse(w, http.StatusOK, "PONG")
+	return
+}
+
+func handleLookup(w http.ResponseWriter, r *http.Request) {
+	var (
+		app = r.Context().Value("app").(app.App)
+	)
+
+	// Read body.
+	b, err := ioutil.ReadAll(r.Body)
+	defer r.Body.Close()
+	if err != nil {
+		app.Logger.WithError(err).Error("error reading request body")
+		sendErrorResponse(w, fmt.Sprintf("Invalid JSON payload"), http.StatusBadRequest, nil)
+		return
+	}
+	// Prepare query flags.
+	var qFlags models.QueryFlags
+	if err := json.Unmarshal(b, &qFlags); err != nil {
+		app.Logger.WithError(err).Error("error unmarshalling payload")
+		sendErrorResponse(w, fmt.Sprintf("Invalid JSON payload"), http.StatusBadRequest, nil)
+		return
+	}
+	app.QueryFlags = qFlags
+	// Load fallbacks.
+	app.LoadFallbacks()
+
+	// Load Questions.
+	app.PrepareQuestions()
+
+	// Load Nameservers.
+	err = app.LoadNameservers()
+	if err != nil {
+		app.Logger.WithError(err).Error("error loading nameservers")
+		sendErrorResponse(w, fmt.Sprintf("Error lookup up for records"), http.StatusInternalServerError, nil)
+	}
+
+	// Load Resolvers.
+	rslvrs, err := resolvers.LoadResolvers(resolvers.Options{
+		Nameservers: app.Nameservers,
+		UseIPv4:     app.QueryFlags.UseIPv4,
+		UseIPv6:     app.QueryFlags.UseIPv6,
+		SearchList:  app.ResolverOpts.SearchList,
+		Ndots:       app.ResolverOpts.Ndots,
+		Timeout:     app.QueryFlags.Timeout * time.Second,
+		Logger:      app.Logger,
+	})
+	if err != nil {
+		app.Logger.WithError(err).Error("error loading resolver")
+		sendErrorResponse(w, fmt.Sprintf("Error lookup up for records"), http.StatusInternalServerError, nil)
+
+	}
+	app.Resolvers = rslvrs
+
+	var responses []resolvers.Response
+	for _, q := range app.Questions {
+		for _, rslv := range app.Resolvers {
+			resp, err := rslv.Lookup(q)
+			if err != nil {
+				app.Logger.WithError(err).Error("error looking up DNS records")
+				app.Logger.Exit(2)
+			}
+			responses = append(responses, resp)
+		}
+	}
+	sendResponse(w, http.StatusOK, responses)
+	return
+}
+
+// wrap is a middleware that wraps HTTP handlers and injects the "app" context.
+func wrap(app app.App, next http.HandlerFunc) http.HandlerFunc {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		ctx := context.WithValue(r.Context(), "app", app)
+		next.ServeHTTP(w, r.WithContext(ctx))
+	})
+}
+
+// sendResponse sends a JSON envelope to the HTTP response.
+func sendResponse(w http.ResponseWriter, code int, data interface{}) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.WriteHeader(code)
+
+	out, err := json.Marshal(httpResp{Status: "success", Data: data})
+	if err != nil {
+		sendErrorResponse(w, "Internal Server Error", http.StatusInternalServerError, nil)
+		return
+	}
+
+	w.Write(out)
+}
+
+// sendErrorResponse sends a JSON error envelope to the HTTP response.
+func sendErrorResponse(w http.ResponseWriter, message string, code int, data interface{}) {
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	w.WriteHeader(code)
+
+	resp := httpResp{Status: "error",
+		Message: message,
+		Data:    data}
+	out, _ := json.Marshal(resp)
+	w.Write(out)
+}

cmd/doggo/cli/cli.go

@@ -17,14 +17,11 @@ var (
 	// Version and date of the build. This is injected at build-time.
 	buildVersion = "unknown"
 	buildDate    = "unknown"
+	logger       = utils.InitLogger()
+	k            = koanf.New(".")
 )
 
 func main() {
-	var (
-		logger = utils.InitLogger()
-		k      = koanf.New(".")
-	)
-
 	// Initialize app.
 	app := app.New(logger, buildVersion)
 

config-api-sample.toml

@@ -0,0 +1,9 @@
+[server]
+address = ":8080"
+name = "doggo-api"
+# WARNING If these timeouts are less than 1s,
+# the server connection breaks.
+read_timeout=7000
+write_timeout=7000
+keepalive_timeout=5000
+max_body_size=10000

pkg/models/models.go

@@ -24,12 +24,12 @@ type QueryFlags struct {
 	Nameservers      []string      `koanf:"nameservers" json:"nameservers"`
 	UseIPv4          bool          `koanf:"ipv4" json:"ipv4"`
 	UseIPv6          bool          `koanf:"ipv6" json:"ipv6"`
-	DisplayTimeTaken bool          `koanf:"time" json:"-"`
-	ShowJSON         bool          `koanf:"json" json:"-"`
-	UseSearchList    bool          `koanf:"search" json:"-"`
 	Ndots            int           `koanf:"ndots" json:"ndots"`
 	Color            bool          `koanf:"color" json:"color"`
 	Timeout          time.Duration `koanf:"timeout" json:"timeout"`
+	DisplayTimeTaken bool          `koanf:"time" json:"-"`
+	ShowJSON         bool          `koanf:"json" json:"-"`
+	UseSearchList    bool          `koanf:"search" json:"-"`
 }
 
 // Nameserver represents the type of Nameserver

www/api/api.md

@@ -0,0 +1,13 @@
+# Usage
+
+```
+curl --request POST \
+  --url http://localhost:8080/lookup/ \
+  --header 'Content-Type: application/json' \
+  --data '{
+	"query": ["mrkaran.dev"],
+	"type": ["A"],
+	"class": ["IN"],
+	"nameservers": ["9.9.9.9"]
+}'
+```