Merge pull request #107 from EmmEff/impl-build-context

Build context files support

Author: EmmEff

client/build_context.go

@@ -34,14 +34,18 @@ func writeArchive(w io.Writer, fsys fs.FS, paths []string) error {
 
 	for _, path := range paths {
 		if err := ar.WriteFiles(path); err != nil {
-			return fmt.Errorf("failed to write to archive: %w", err)
+			return err
 		}
 	}
 
 	return nil
 }
 
+var errContextAlreadyPresent = errors.New("build context already present")
+
 // getBuildContextUploadLocation obtains an upload location for a build context.
+//
+// If errContextAlreadyPresent is returned, (re)upload of build context is not required.
 func (c *Client) getBuildContextUploadLocation(ctx context.Context, size int64, digest string) (*url.URL, error) {
 	ref := &url.URL{
 		Path: "v1/build-context",
@@ -76,6 +80,11 @@ func (c *Client) getBuildContextUploadLocation(ctx context.Context, size int64,
 		return nil, fmt.Errorf("%w", errorFromResponse(res))
 	}
 
+	if res.Header.Get("Location") == "" {
+		// "Location" header is not present; build context does not need to be uploaded
+		return nil, errContextAlreadyPresent
+	}
+
 	return url.Parse(res.Header.Get("Location"))
 }
 
@@ -127,6 +136,9 @@ func (c *Client) uploadBuildContext(ctx context.Context, rw io.ReadWriteSeeker,
 	// Get the build context upload location.
 	loc, err := c.getBuildContextUploadLocation(ctx, size, digest)
 	if err != nil {
+		if errors.Is(err, errContextAlreadyPresent) {
+			return digest, nil
+		}
 		return "", fmt.Errorf("failed to get build context upload location: %w", err)
 	}
 

cmd/scs-build/build.go

@@ -113,19 +113,5 @@ func executeBuildCmd(cmd *cobra.Command, args []string) error {
 		cancel()
 	}()
 
-	archsToBuild := v.GetStringSlice(keyArch)
-
-	if len(archsToBuild) > 1 {
-		fmt.Printf("Performing build for following architectures: %v\n", strings.Join(archsToBuild, " "))
-	}
-
-	for _, arch := range v.GetStringSlice(keyArch) {
-		fmt.Printf("Building for %v...\n", arch)
-
-		if err := app.Run(ctx, arch); err != nil {
-			return fmt.Errorf("failed to build %v: %w", arch, err)
-		}
-	}
-
-	return nil
+	return app.Run(ctx, v.GetStringSlice(keyArch))
 }

internal/app/buildclient/build.go

@@ -11,17 +11,19 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"strings"
 
 	build "github.com/sylabs/scs-build-client/client"
 )
 
-// buildArtifact sends a build request for the specified def and arch, optionally publishing it to
+// buildArtifact sends a build request for the specified arch, optionally publishing it to
 // libraryRef. Output is streamed to standard output. If the build cannot be submitted, or does not
 // succeed, an error is returned.
-func (app *App) buildArtifact(ctx context.Context, def []byte, arch string, libraryRef string) (*build.BuildInfo, error) {
-	bi, err := app.buildClient.Submit(ctx, bytes.NewReader(def),
+func (app *App) buildArtifact(ctx context.Context, arch, libraryRef, digest string, rawDef []byte) (*build.BuildInfo, error) {
+	bi, err := app.buildClient.Submit(ctx, bytes.NewReader(rawDef),
 		build.OptBuildLibraryRef(libraryRef),
 		build.OptBuildArchitecture(arch),
+		build.OptBuildContext(digest),
 	)
 	if err != nil {
 		return nil, fmt.Errorf("error submitting remote build: %w", err)
@@ -36,8 +38,46 @@ func (app *App) buildArtifact(ctx context.Context, def []byte, arch string, libr
 	// The returned info doesn't indicate an exit code, but a zero-sized image tells us something
 	// went wrong.
 	if bi.ImageSize() <= 0 {
-		return bi, errors.New("failed to build image")
+		return nil, errors.New("failed to build image")
+	}
+
+	if digest != "" {
+		_ = app.buildClient.DeleteBuildContext(ctx, digest)
 	}
 
 	return bi, nil
 }
+
+// definitionFromURI attempts to parse a URI from raw. If raw contains a URI, a definition file
+// representing it is returned, and ok is set to true. Otherwise, ok is set to false.
+func definitionFromURI(raw string) (def []byte, ok bool) {
+	var u []string
+	if strings.Contains(raw, "://") {
+		u = strings.SplitN(raw, "://", 2)
+	} else if strings.Contains(raw, ":") {
+		u = strings.SplitN(raw, ":", 2)
+	} else {
+		return nil, false
+	}
+
+	var b bytes.Buffer
+
+	fmt.Fprintln(&b, "bootstrap:", u[0])
+	fmt.Fprintln(&b, "from:", u[1])
+
+	return b.Bytes(), true
+}
+
+func (app *App) getBuildDef() ([]byte, error) {
+	// Build spec could be a URI, or the path to a definition file.
+	if b, ok := definitionFromURI(app.buildSpec); ok {
+		return b, nil
+	}
+
+	// Attempt to read app.buildSpec as a file
+	b, err := os.ReadFile(app.buildSpec)
+	if err != nil {
+		return nil, fmt.Errorf("error reading def file %v: %w", app.buildSpec, err)
+	}
+	return b, nil
+}

internal/app/buildclient/build_test.go

@@ -0,0 +1,50 @@
+// Copyright (c) 2022, Sylabs Inc. All rights reserved.
+// This software is licensed under a 3-clause BSD license. Please consult the
+// LICENSE.md file distributed with the sources of this project regarding your
+// rights to use or distribute this software.
+
+package buildclient
+
+import "testing"
+
+func Test_definitionFromURI(t *testing.T) {
+	tests := []struct {
+		name    string
+		raw     string
+		wantDef string
+		wantOK  bool
+	}{
+		{
+			name:   "NonURI",
+			raw:    "file.txt",
+			wantOK: false,
+		},
+		{
+			name:    "Docker",
+			raw:     "docker://alpine",
+			wantDef: "bootstrap: docker\nfrom: alpine\n",
+			wantOK:  true,
+		},
+		{
+			name:    "Library",
+			raw:     "library://alpine",
+			wantDef: "bootstrap: library\nfrom: alpine\n",
+			wantOK:  true,
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+
+		t.Run(tt.name, func(t *testing.T) {
+			def, ok := definitionFromURI(tt.raw)
+
+			if got, want := string(def), tt.wantDef; got != want {
+				t.Errorf("got def %#v, want %#v", got, want)
+			}
+
+			if got, want := ok, tt.wantOK; got != want {
+				t.Errorf("got OK %v, want %v", got, want)
+			}
+		})
+	}
+}