Initial commit

internal/external.go

@@ -0,0 +1,93 @@
+package internal
+
+import (
+	"context"
+	"net"
+	"net/http"
+	"net/url"
+	"time"
+
+	"github.com/pkg/errors"
+	"golang.org/x/text/language"
+	"golang.org/x/text/message/catalog"
+)
+
+var ErrInvalidResponseCode = errors.New("invalid response status code")
+
+func NewExternalLoader(baseURL string, header http.Header) *ExternalLoader {
+	client := http.Client{
+		Transport: &http.Transport{
+			DialContext: (&net.Dialer{
+				Timeout: 2 * time.Second,
+			}).DialContext,
+			DisableKeepAlives:      true,
+			MaxIdleConns:           1,
+			MaxIdleConnsPerHost:    1,
+			MaxConnsPerHost:        2,
+			IdleConnTimeout:        30 * time.Second,
+			ResponseHeaderTimeout:  5 * time.Second,
+			MaxResponseHeaderBytes: 1024 * 3,
+			WriteBufferSize:        100,
+			ReadBufferSize:         1024 * 8,
+		},
+		Timeout: time.Second * 10,
+	}
+
+	return NewExternalLoaderWithClient(baseURL, header, &client)
+}
+
+func NewExternalLoaderWithClient(baseURL string, header http.Header, client *http.Client) *ExternalLoader {
+	return &ExternalLoader{baseURL: baseURL, client: client, header: header}
+}
+
+type ExternalLoader struct {
+	baseURL string
+	header  http.Header
+	client  *http.Client
+}
+
+func (e *ExternalLoader) Load(builder *catalog.Builder) error {
+	languages := builder.Languages()
+
+	for _, lang := range languages {
+		if err := e.load(lang, builder); err != nil {
+			return errors.WithMessagef(err, "load translation for %s", lang.String())
+		}
+	}
+
+	return nil
+}
+
+func (e *ExternalLoader) load(lang language.Tag, builder *catalog.Builder) error {
+	langURL, err := url.JoinPath(e.baseURL, lang.String())
+	if err != nil {
+		return errors.Wrap(err, "join url path")
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, langURL, nil)
+	if err != nil {
+		return errors.Wrap(err, "new request")
+	}
+
+	if e.header != nil {
+		req.Header = e.header
+	}
+
+	response, err := e.client.Do(req)
+	if err != nil {
+		return errors.Wrap(err, "do request")
+	}
+
+	if response.StatusCode != http.StatusOK {
+		return errors.Wrapf(ErrInvalidResponseCode, "got status %d", response.StatusCode)
+	}
+
+	if err := load(response.Body, lang, builder); err != nil {
+		return errors.WithMessage(err, "load translation")
+	}
+
+	return nil
+}