Add a test for writing failure

pkg/geoipupdate/geoip_updater_test.go

@@ -1,19 +1,26 @@
 package geoipupdate
 
 import (
+	"archive/tar"
 	"bytes"
+	"compress/gzip"
 	"context"
 	"encoding/json"
 	"errors"
 	"log"
+	"net/http"
+	"net/http/httptest"
+	"os"
 	"path/filepath"
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"golang.org/x/net/http2"
 
 	"github.com/maxmind/geoipupdate/v6/pkg/geoipupdate/database"
+	"github.com/maxmind/geoipupdate/v6/pkg/geoipupdate/internal"
 )
 
 // TestClientOutput makes sure that the client outputs the result of it's
@@ -96,6 +103,125 @@ func TestClientOutput(t *testing.T) {
 	require.ErrorIs(t, err, streamErr)
 }
 
+func TestRetryWhenWriting(t *testing.T) {
+	tempDir := t.TempDir()
+
+	databaseDir := filepath.Join(tempDir, "databases")
+
+	// Create a databases folder
+	err := os.MkdirAll(databaseDir, 0o750)
+	require.NoError(t, err)
+
+	try := 0
+	sv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		// Mocking the metadata endpoint.
+		if r.URL.Path == "/geoip/updates/metadata" {
+			w.Header().Set("Content-Type", "application/json")
+
+			// The md5 here bleongs to the tar.gz sent below.
+			metadata := []byte(
+				`{"databases":[{"edition_id":"foo-db-name",` +
+					`"md5":"83e01ba43c2a66e30cb3007c1a300c78","date":"2023-04-27"}]}`)
+			_, err := w.Write(metadata)
+			require.NoError(t, err)
+
+			return
+		}
+
+		w.Header().Set("Last-Modified", "Wed, 27 Apr 2023 12:04:48 GMT")
+
+		gzWriter := gzip.NewWriter(w)
+		defer gzWriter.Close()
+		tarWriter := tar.NewWriter(gzWriter)
+		defer tarWriter.Close()
+
+		info := mockFileInfo{
+			name: "foo-db-name.mmdb",
+			size: 1000,
+		}
+		header, err := tar.FileInfoHeader(info, info.Name())
+		require.NoError(t, err)
+		header.Name = "foo-db-name.mmdb"
+
+		// Create a tar Header from the FileInfo data
+		err = tarWriter.WriteHeader(header)
+		require.NoError(t, err)
+
+		bytesToWrite := 1000
+		if try == 0 {
+			// In the first try, we create a bad tar.gz file.
+			// That has less than the size defined in the header.
+			bytesToWrite = 100
+		}
+
+		for i := 0; i < bytesToWrite; i++ {
+			_, err = tarWriter.Write([]byte("t"))
+			require.NoError(t, err)
+		}
+		try++
+	}))
+	defer sv.Close()
+
+	config := &Config{
+		URL:               sv.URL,
+		EditionIDs:        []string{"foo-db-name"},
+		LockFile:          filepath.Join(tempDir, ".geoipupdate.lock"),
+		Output:            true,
+		Parallelism:       1,
+		RetryFor:          5 * time.Minute,
+		DatabaseDirectory: databaseDir,
+	}
+
+	logOutput := &bytes.Buffer{}
+
+	c := &Client{
+		config: config,
+		getReader: func() (database.Reader, error) {
+			return database.NewHTTPReader(
+				config.Proxy,
+				config.URL,
+				config.AccountID,
+				config.LicenseKey,
+				config.Verbose,
+			), nil
+		},
+		getWriter: func() (database.Writer, error) {
+			return database.NewLocalFileWriter(
+				config.DatabaseDirectory,
+				config.PreserveFileTimes,
+				config.Verbose,
+			)
+		},
+		output: log.New(logOutput, "", 0),
+	}
+
+	ctx := context.Background()
+
+	reader, err := c.getReader()
+	require.NoError(t, err)
+
+	writer, err := c.getWriter()
+	require.NoError(t, err)
+
+	jobProcessor := internal.NewJobProcessor(ctx, 1)
+	processFunc := func(ctx context.Context) error {
+		_, err = c.downloadEdition(
+			ctx,
+			"foo-db-name",
+			reader,
+			writer,
+		)
+
+		return err
+	}
+	jobProcessor.Add(processFunc)
+
+	err = jobProcessor.Run(ctx)
+	require.NoError(t, err)
+
+	assert.Empty(t, logOutput.String())
+}
+
 type mockReader struct {
 	i      int
 	result []database.ReadResult
@@ -126,3 +252,32 @@ func (w mockWriter) GetHash(_ string) (string, error) { return "", nil }
 func afterOrEqual(t1, t2 time.Time) bool {
 	return t1.After(t2) || t1.Equal(t2)
 }
+
+type mockFileInfo struct {
+	name string
+	size int64
+}
+
+func (info mockFileInfo) Name() string {
+	return info.name
+}
+
+func (info mockFileInfo) Size() int64 {
+	return info.size
+}
+
+func (info mockFileInfo) IsDir() bool {
+	return false
+}
+
+func (info mockFileInfo) Mode() os.FileMode {
+	return 0
+}
+
+func (info mockFileInfo) ModTime() time.Time {
+	return time.Now()
+}
+
+func (info mockFileInfo) Sys() any {
+	return nil
+}