feat: external ip provider plain

pkg/externalIpProvider/plain/plain.go

@@ -0,0 +1,56 @@
+package externalIpProvider
+
+import (
+	"errors"
+	"net"
+	"net/http"
+	"net/url"
+	externalIpProvider "realdnydns/pkg/externalIpProvider"
+)
+
+type ExternalIpProviderImplPlain struct {
+	IPProviderURL string
+	HTTPClient    *http.Client
+}
+
+type PlainExternalIpProviderConfig struct {
+	Url string `yaml:"url"`
+}
+
+func New(config PlainExternalIpProviderConfig) (externalIpProvider.ExternalIpProvider, error) {
+	if config.Url == "" {
+		return nil, errors.New("url is required")
+	}
+
+	return &ExternalIpProviderImplPlain{
+		config.Url,
+		&http.Client{},
+	}, nil
+}
+
+func (p *ExternalIpProviderImplPlain) GetExternalIp() (net.IP, error) {
+	parsedUrl, err := url.Parse(p.IPProviderURL)
+	if err != nil {
+		return nil, err
+	}
+
+	res, err := p.HTTPClient.Get(parsedUrl.String())
+	if err != nil {
+		return nil, err
+	}
+
+	if res.StatusCode != 200 {
+		return nil, errors.New("unexpected status code")
+	}
+
+	responseBody := make([]byte, res.ContentLength)
+	res.Body.Read(responseBody)
+	defer res.Body.Close()
+
+	parsedIp := net.ParseIP(string(responseBody))
+	if parsedIp == nil {
+		return nil, errors.New("unable to parse ip")
+	}
+
+	return parsedIp, nil
+}

pkg/externalIpProvider/plain/plain_test.go

@@ -0,0 +1,150 @@
+package externalIpProvider
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestNew(t *testing.T) {
+	t.Run("returns external ip provider", testNew())
+	t.Run("returns error when url is empty", testNewEmptyUrl())
+}
+
+func testNew() func(t *testing.T) {
+	return func(t *testing.T) {
+		provider, err := New(PlainExternalIpProviderConfig{
+			Url: "http://localhost",
+		})
+		if err != nil {
+			t.Fatalf("NewPlain() returned unexpected error: %v", err)
+		}
+
+		if provider == nil {
+			t.Fatalf("NewPlain() returned nil provider")
+		}
+	}
+}
+
+func testNewEmptyUrl() func(t *testing.T) {
+	return func(t *testing.T) {
+		_, err := New(PlainExternalIpProviderConfig{})
+		if err == nil {
+			t.Fatalf("NewPlain() returned unexpected error: %v", err)
+		}
+	}
+}
+
+func TestGetExternal(t *testing.T) {
+	t.Run("returns external ip", testGetExternalIp())
+	t.Run("returns error when unable to parse ip", testGetExternalIpUnparsableIp())
+	t.Run("returns error when unexpected status code", testGetExternalIpUnexpectedStatusCode())
+	t.Run("returns error when unable to parse url", testGetExternalIpUnableToParseUrl())
+	t.Run("returns error when unable to get", testGetExternalIpUnableToGet())
+}
+
+func testGetExternalIp() func(t *testing.T) {
+	return func(t *testing.T) {
+		mockServer := httptest.NewServer(http.HandlerFunc(
+			func(w http.ResponseWriter, r *http.Request) {
+				w.Write([]byte("127.0.0.1"))
+			},
+		))
+		defer mockServer.Close()
+
+		provider, err := New(PlainExternalIpProviderConfig{
+			Url: mockServer.URL,
+		})
+		if err != nil {
+			t.Fatalf("NewPlain() returned unexpected error: %v", err)
+		}
+
+		ip, err := provider.GetExternalIp()
+		if err != nil {
+			t.Fatalf("GetExternalIp() returned unexpected error: %v", err)
+		}
+
+		if ip.String() != "127.0.0.1" {
+			t.Fatalf("GetExternalIp() returned unexpected ip: %v instead of 127.0.0.1", ip)
+		}
+	}
+}
+
+func testGetExternalIpUnparsableIp() func(t *testing.T) {
+	return func(t *testing.T) {
+		mockServer := httptest.NewServer(http.HandlerFunc(
+			func(w http.ResponseWriter, r *http.Request) {
+				w.Write([]byte("not an ip"))
+			},
+		))
+		defer mockServer.Close()
+
+		provider, err := New(PlainExternalIpProviderConfig{
+			Url: mockServer.URL,
+		})
+		if err != nil {
+			t.Fatalf("NewPlain() returned unexpected error: %v", err)
+		}
+
+		_, err = provider.GetExternalIp()
+		if err == nil {
+			t.Fatalf("GetExternalIp() returned unexpected error: %v", err)
+		}
+	}
+}
+
+func testGetExternalIpUnexpectedStatusCode() func(t *testing.T) {
+	return func(t *testing.T) {
+		mockServer := httptest.NewServer(http.HandlerFunc(
+			func(w http.ResponseWriter, r *http.Request) {
+				w.WriteHeader(500)
+			},
+		))
+		defer mockServer.Close()
+
+		provider, err := New(PlainExternalIpProviderConfig{
+			Url: mockServer.URL,
+		})
+		if err != nil {
+			t.Fatalf("NewPlain() returned unexpected error: %v", err)
+		}
+
+		_, err = provider.GetExternalIp()
+		if err == nil {
+			t.Fatalf("GetExternalIp() returned unexpected error: %v", err)
+		}
+	}
+}
+
+func testGetExternalIpUnableToParseUrl() func(t *testing.T) {
+	return func(t *testing.T) {
+		provider, err := New(PlainExternalIpProviderConfig{
+			Url: "not a url !'§%&",
+		})
+		if err != nil {
+			t.Fatalf("NewPlain() returned unexpected error: %v", err)
+		}
+
+		_, err = provider.GetExternalIp()
+		if err == nil {
+			t.Fatalf("GetExternalIp() returned unexpected error: %v", err)
+		}
+	}
+}
+
+func testGetExternalIpUnableToGet() func(t *testing.T) {
+	return func(t *testing.T) {
+		// force error by using a non-responding url, beware of side effects
+		provider, err := New(PlainExternalIpProviderConfig{
+			Url: "http://localhost:1234",
+		})
+		if err != nil {
+			t.Fatalf("NewPlain() returned unexpected error: %v", err)
+		}
+
+		_, err = provider.GetExternalIp()
+		if err == nil {
+			t.Fatalf("GetExternalIp() returned unexpected error: %v", err)
+		}
+	}
+}