refactor(thumbnails): thread context.Context through the preprocessor Convert interface

The Tika preview extractor does a network call; it was using context.Background().
Pass the request context from the gRPC handler through Convert so the unpack call
respects cancellation and deadlines. Non-I/O decoders ignore the context.

services/thumbnails/pkg/preprocessor/preprocessor.go

@@ -4,6 +4,7 @@ import (
 	"archive/zip"
 	"bufio"
 	"bytes"
+	"context"
 	"encoding/base64"
 	"encoding/json"
 	"image"
@@ -26,14 +27,14 @@ import (
 
 // FileConverter is the interface for the file converter
 type FileConverter interface {
-	Convert(r io.Reader) (any, error)
+	Convert(ctx context.Context, r io.Reader) (any, error)
 }
 
 // GifDecoder is a converter for the gif file
 type GifDecoder struct{}
 
 // Convert reads the gif file and returns the thumbnail image
-func (i GifDecoder) Convert(r io.Reader) (any, error) {
+func (i GifDecoder) Convert(_ context.Context, r io.Reader) (any, error) {
 	img, err := gif.DecodeAll(r)
 	if err != nil {
 		return nil, errors.Wrap(err, `could not decode the image`)
@@ -45,7 +46,7 @@ func (i GifDecoder) Convert(r io.Reader) (any, error) {
 type GgsDecoder struct{ thumbnailpath string }
 
 // Convert reads the ggs file and returns the thumbnail image
-func (g GgsDecoder) Convert(r io.Reader) (any, error) {
+func (g GgsDecoder) Convert(ctx context.Context, r io.Reader) (any, error) {
 	var buf bytes.Buffer
 	_, err := io.Copy(&buf, r)
 	if err != nil {
@@ -65,7 +66,7 @@ func (g GgsDecoder) Convert(r io.Reader) (any, error) {
 			if converter == nil {
 				return nil, thumbnailerErrors.ErrNoConverterForExtractedImageFromGgsFile
 			}
-			img, err := converter.Convert(thumbnail)
+			img, err := converter.Convert(ctx, thumbnail)
 			if err != nil {
 				return nil, errors.Wrap(err, `could not decode the image`)
 			}
@@ -79,7 +80,7 @@ func (g GgsDecoder) Convert(r io.Reader) (any, error) {
 type AudioDecoder struct{}
 
 // Convert reads the audio file and extracts the thumbnail image from the id3 tag
-func (i AudioDecoder) Convert(r io.Reader) (any, error) {
+func (i AudioDecoder) Convert(ctx context.Context, r io.Reader) (any, error) {
 	b, err := io.ReadAll(r)
 	if err != nil {
 		return nil, err
@@ -99,7 +100,7 @@ func (i AudioDecoder) Convert(r io.Reader) (any, error) {
 		return nil, thumbnailerErrors.ErrNoConverterForExtractedImageFromAudioFile
 	}
 
-	return converter.Convert(bytes.NewReader(picture.Data))
+	return converter.Convert(ctx, bytes.NewReader(picture.Data))
 }
 
 // TxtToImageConverter is a converter for the text file
@@ -108,7 +109,7 @@ type TxtToImageConverter struct {
 }
 
 // Convert reads the text file and renders it into a thumbnail image
-func (t TxtToImageConverter) Convert(r io.Reader) (any, error) {
+func (t TxtToImageConverter) Convert(_ context.Context, r io.Reader) (any, error) {
 	img := image.NewRGBA(image.Rect(0, 0, 640, 480))
 
 	imgBounds := img.Bounds()
@@ -203,7 +204,7 @@ type GGPStruct struct {
 type GgpDecoder struct{}
 
 // Convert reads the ggp file and returns the first thumbnail image
-func (j GgpDecoder) Convert(r io.Reader) (any, error) {
+func (j GgpDecoder) Convert(_ context.Context, r io.Reader) (any, error) {
 	ggp := &GGPStruct{}
 	err := json.NewDecoder(r).Decode(ggp)
 	if err != nil {

services/thumbnails/pkg/preprocessor/preprocessor_imaging.go

@@ -3,6 +3,7 @@
 package preprocessor
 
 import (
+	"context"
 	"io"
 
 	"github.com/kovidgoyal/imaging"
@@ -13,7 +14,7 @@ import (
 type ImageDecoder struct{}
 
 // Convert reads the image file and returns the thumbnail image
-func (i ImageDecoder) Convert(r io.Reader) (any, error) {
+func (i ImageDecoder) Convert(_ context.Context, r io.Reader) (any, error) {
 	img, err := imaging.Decode(r, imaging.AutoOrientation(true))
 	if err != nil {
 		return nil, errors.Wrap(err, `could not decode the image`)

services/thumbnails/pkg/preprocessor/preprocessor_test.go

@@ -2,6 +2,7 @@ package preprocessor
 
 import (
 	"bytes"
+	"context"
 	"io"
 	"os"
 	"testing"
@@ -32,14 +33,14 @@ var _ = Describe("ImageDecoder", func() {
 
 		It("should decode an image", func() {
 			decoder := ImageDecoder{}
-			img, err := decoder.Convert(fileReader)
+			img, err := decoder.Convert(context.TODO(), fileReader)
 			Expect(err).ToNot(HaveOccurred())
 			Expect(img).ToNot(BeNil())
 		})
 
 		It("should return an error if the image is invalid", func() {
 			decoder := ImageDecoder{}
-			img, err := decoder.Convert(bytes.NewReader([]byte("not an image")))
+			img, err := decoder.Convert(context.TODO(), bytes.NewReader([]byte("not an image")))
 			Expect(err).To(HaveOccurred())
 			Expect(img).To(BeNil())
 		})
@@ -57,14 +58,14 @@ var _ = Describe("ImageDecoder", func() {
 
 		It("should decode a gif", func() {
 			decoder := GifDecoder{}
-			img, err := decoder.Convert(fileReader)
+			img, err := decoder.Convert(context.TODO(), fileReader)
 			Expect(err).ToNot(HaveOccurred())
 			Expect(img).ToNot(BeNil())
 		})
 
 		It("should return an error if the gif is invalid", func() {
 			decoder := GifDecoder{}
-			img, err := decoder.Convert(bytes.NewReader([]byte("not a gif")))
+			img, err := decoder.Convert(context.TODO(), bytes.NewReader([]byte("not a gif")))
 			Expect(err).To(HaveOccurred())
 			Expect(img).To(BeNil())
 		})
@@ -82,14 +83,14 @@ var _ = Describe("ImageDecoder", func() {
 
 		It("should decode a ggs", func() {
 			decoder := GgsDecoder{"_slide0/geogebra_thumbnail.png"}
-			img, err := decoder.Convert(fileReader)
+			img, err := decoder.Convert(context.TODO(), fileReader)
 			Expect(err).ToNot(HaveOccurred())
 			Expect(img).ToNot(BeNil())
 		})
 
 		It("should return an error if the ggs is invalid", func() {
 			decoder := GgsDecoder{"_slide0/geogebra_thumbnail.png"}
-			img, err := decoder.Convert(bytes.NewReader([]byte("not a ggs")))
+			img, err := decoder.Convert(context.TODO(), bytes.NewReader([]byte("not a ggs")))
 			Expect(err).To(HaveOccurred())
 			Expect(img).To(BeNil())
 		})
@@ -104,7 +105,7 @@ var _ = Describe("ImageDecoder", func() {
 			}
 			fileReader = bytes.NewReader(fileContent)
 			decoder := AudioDecoder{}
-			img, err := decoder.Convert(fileReader)
+			img, err := decoder.Convert(context.TODO(), fileReader)
 			Expect(err).ToNot(HaveOccurred())
 			Expect(img).ToNot(BeNil())
 		})
@@ -115,13 +116,13 @@ var _ = Describe("ImageDecoder", func() {
 			}
 			fileReader = bytes.NewReader(fileContent)
 			decoder := AudioDecoder{}
-			img, err := decoder.Convert(fileReader)
+			img, err := decoder.Convert(context.TODO(), fileReader)
 			Expect(err).To(HaveOccurred())
 			Expect(img).To(BeNil())
 		})
 		It("should return an error if the audio is invalid", func() {
 			decoder := AudioDecoder{}
-			img, err := decoder.Convert(bytes.NewReader([]byte("not an audio")))
+			img, err := decoder.Convert(context.TODO(), bytes.NewReader([]byte("not an audio")))
 			Expect(err).To(HaveOccurred())
 			Expect(img).To(BeNil())
 		})
@@ -145,7 +146,7 @@ var _ = Describe("ImageDecoder", func() {
 			}
 		})
 		It("should decode a text", func() {
-			img, err := decoder.Convert(bytes.NewReader([]byte("This is a test text")))
+			img, err := decoder.Convert(context.TODO(), bytes.NewReader([]byte("This is a test text")))
 			Expect(err).ToNot(HaveOccurred())
 			Expect(img).ToNot(BeNil())
 		})
@@ -156,7 +157,7 @@ var _ = Describe("ImageDecoder", func() {
 					DefaultFont: "/some/unknown/font.otf",
 				},
 			}
-			img, err := decoder.Convert(bytes.NewReader([]byte("This is a test text")))
+			img, err := decoder.Convert(context.TODO(), bytes.NewReader([]byte("This is a test text")))
 			Expect(err).To(HaveOccurred())
 			Expect(img).To(BeNil())
 		})

services/thumbnails/pkg/preprocessor/preprocessor_vips.go

@@ -3,6 +3,7 @@
 package preprocessor
 
 import (
+	"context"
 	"io"
 
 	"github.com/davidbyttow/govips/v2/vips"
@@ -14,7 +15,7 @@ func init() {
 
 type ImageDecoder struct{}
 
-func (v ImageDecoder) Convert(r io.Reader) (interface{}, error) {
+func (v ImageDecoder) Convert(_ context.Context, r io.Reader) (interface{}, error) {
 	img, err := vips.NewImageFromReader(r)
 	return img, err
 }

services/thumbnails/pkg/preprocessor/tika.go

@@ -27,16 +27,16 @@ type TikaDecoder struct {
 	filename string
 }
 
-func (d TikaDecoder) Convert(r io.Reader) (any, error) {
+func (d TikaDecoder) Convert(ctx context.Context, r io.Reader) (any, error) {
 	data, err := io.ReadAll(r)
 	if err != nil {
 		return nil, err
 	}
-	preview, err := tikaExtractPreview(context.Background(), d.tikaURL, d.filename, data)
+	preview, err := tikaExtractPreview(ctx, d.tikaURL, d.filename, data)
 	if err != nil {
 		return nil, err
 	}
-	return ForType("image/jpeg", nil).Convert(bytes.NewReader(preview))
+	return ForType("image/jpeg", nil).Convert(ctx, bytes.NewReader(preview))
 }
 
 var tikaHTTPClient = &http.Client{Timeout: 30 * time.Second}

services/thumbnails/pkg/preprocessor/tika_test.go

@@ -3,6 +3,7 @@ package preprocessor
 import (
 	"archive/zip"
 	"bytes"
+	"context"
 	"image"
 	"image/jpeg"
 	"io"
@@ -62,7 +63,7 @@ var _ = Describe("TikaDecoder", func() {
 		}))
 		defer srv.Close()
 
-		img, err := TikaDecoder{tikaURL: srv.URL}.Convert(bytes.NewReader([]byte("raw")))
+		img, err := TikaDecoder{tikaURL: srv.URL}.Convert(context.TODO(), bytes.NewReader([]byte("raw")))
 		Expect(err).ToNot(HaveOccurred())
 		// default (imaging) build decodes to an image.Image
 		bounds := img.(image.Image).Bounds()
@@ -76,7 +77,7 @@ var _ = Describe("TikaDecoder", func() {
 		}))
 		defer srv.Close()
 
-		_, err := TikaDecoder{tikaURL: srv.URL}.Convert(bytes.NewReader([]byte("raw")))
+		_, err := TikaDecoder{tikaURL: srv.URL}.Convert(context.TODO(), bytes.NewReader([]byte("raw")))
 		Expect(err).To(MatchError(thumbnailerErrors.ErrNoImageFromRawFile))
 	})
 
@@ -86,7 +87,7 @@ var _ = Describe("TikaDecoder", func() {
 		}))
 		defer srv.Close()
 
-		_, err := TikaDecoder{tikaURL: srv.URL}.Convert(bytes.NewReader([]byte("raw")))
+		_, err := TikaDecoder{tikaURL: srv.URL}.Convert(context.TODO(), bytes.NewReader([]byte("raw")))
 		Expect(err).To(HaveOccurred())
 	})
 
@@ -98,7 +99,7 @@ var _ = Describe("TikaDecoder", func() {
 		}))
 		defer srv.Close()
 
-		_, err := TikaDecoder{tikaURL: srv.URL, filename: "my photo.nef"}.Convert(bytes.NewReader([]byte("raw")))
+		_, err := TikaDecoder{tikaURL: srv.URL, filename: "my photo.nef"}.Convert(context.TODO(), bytes.NewReader([]byte("raw")))
 		Expect(err).ToNot(HaveOccurred())
 		Expect(gotCD).To(Equal(`attachment; filename="my photo.nef"`))
 	})
@@ -112,7 +113,7 @@ var _ = Describe("TikaDecoder", func() {
 		}))
 		defer srv.Close()
 
-		img, err := TikaDecoder{tikaURL: srv.URL}.Convert(bytes.NewReader([]byte("raw")))
+		img, err := TikaDecoder{tikaURL: srv.URL}.Convert(context.TODO(), bytes.NewReader([]byte("raw")))
 		Expect(err).ToNot(HaveOccurred())
 		Expect(img.(image.Image).Bounds().Dx()).To(Equal(16))
 	})
@@ -123,7 +124,7 @@ var _ = Describe("TikaDecoder", func() {
 		}))
 		defer srv.Close()
 
-		_, err := TikaDecoder{tikaURL: srv.URL}.Convert(bytes.NewReader([]byte("raw")))
+		_, err := TikaDecoder{tikaURL: srv.URL}.Convert(context.TODO(), bytes.NewReader([]byte("raw")))
 		Expect(err).To(MatchError(thumbnailerErrors.ErrNoImageFromRawFile))
 	})
 
@@ -133,7 +134,7 @@ var _ = Describe("TikaDecoder", func() {
 		}))
 		defer srv.Close()
 
-		_, err := TikaDecoder{tikaURL: srv.URL}.Convert(bytes.NewReader([]byte("raw")))
+		_, err := TikaDecoder{tikaURL: srv.URL}.Convert(context.TODO(), bytes.NewReader([]byte("raw")))
 		Expect(err).To(HaveOccurred())
 		Expect(err).ToNot(MatchError(thumbnailerErrors.ErrNoImageFromRawFile))
 	})

services/thumbnails/pkg/service/grpc/v0/service.go

@@ -173,7 +173,7 @@ func (g Thumbnail) handleCS3Source(ctx context.Context, req *thumbnailssvc.GetTh
 		"filename":    sRes.GetInfo().GetName(),
 	}
 	pp := preprocessor.ForType(sRes.GetInfo().GetMimeType(), ppOpts)
-	img, err := pp.Convert(r)
+	img, err := pp.Convert(ctx, r)
 	switch {
 	case errors.Is(err, terrors.ErrNoImageFromRawFile):
 		// a raw file without an embedded preview is expected, not an error
@@ -275,7 +275,7 @@ func (g Thumbnail) handleWebdavSource(ctx context.Context, req *thumbnailssvc.Ge
 		"filename":    sRes.GetInfo().GetName(),
 	}
 	pp := preprocessor.ForType(sRes.GetInfo().GetMimeType(), ppOpts)
-	img, err := pp.Convert(r)
+	img, err := pp.Convert(ctx, r)
 	if img == nil || err != nil {
 		return "", merrors.NotFound(g.serviceID, "could not get image")
 	}

services/thumbnails/pkg/thumbnail/thumbnail_test.go

@@ -1,6 +1,7 @@
 package thumbnail
 
 import (
+	"context"
 	"image"
 	"os"
 	"path"
@@ -176,7 +177,7 @@ func TestPreviewGenerationTooBigImage(t *testing.T) {
 			defer f.Close()
 
 			preproc := preprocessor.ForType(tt.mimeType, nil)
-			convert, err := preproc.Convert(f)
+			convert, err := preproc.Convert(context.TODO(), f)
 			if err != nil {
 				return
 			}