buildkit2303.go

package main

import (
	"context"
	"fmt"
	mrand "math/rand"
	"os"
	"path/filepath"
	"time"

	"github.com/moby/buildkit/client"
	_ "github.com/moby/buildkit/client/connhelper/dockercontainer"
	"github.com/moby/buildkit/frontend/dockerfile/builder"
	gwclient "github.com/moby/buildkit/frontend/gateway/client"
	"github.com/moby/buildkit/util/progress/progresswriter"
	"github.com/pkg/errors"
	"golang.org/x/sync/errgroup"
)

func main() {
	ctx := context.Background()
	eg, ctx := errgroup.WithContext(ctx)
	for i := 0; i < 10; i++ {
		eg.Go(func() error {
			for {
				if err := build(ctx); err != nil {
					return err
				}
			}
		})
	}
	err := eg.Wait()
	if err != nil {
		fmt.Fprintf(os.Stderr, "ERROR: % +v", err)
	}
}

func build(ctx context.Context) error {
	ctx, cancel := context.WithTimeout(ctx, 2*time.Minute)
	defer cancel()
	c, err := client.New(ctx, os.Getenv("BUILDKIT_HOST"))
	if err != nil {
		return err
	}
	defer c.Close()

	pw, err := progresswriter.NewPrinter(context.Background(), os.Stdout, "plain")
	if err != nil {
		return err
	}
	defer func() {
		<-pw.Done()
	}()

	dir, err := os.MkdirTemp("", "context")
	if err != nil {
		return err
	}
	defer os.RemoveAll(dir)

	if err := os.WriteFile(filepath.Join(dir, "Dockerfile"), []byte(`
FROM busybox:latest
RUN touch /foobar
COPY . /stuff
`), 0o644); err != nil {
		return err
	}
	// prevent /moby.buildkit.v1.frontend.LLBBridge/ReadFile errors when
	// dockerignore files don't exist
	if err := os.WriteFile(filepath.Join(dir, "Dockerfile.dockerignore"), []byte(``), 0o644); err != nil {
		return err
	}
	if err := os.WriteFile(filepath.Join(dir, ".dockerignore"), []byte(``), 0o644); err != nil {
		return err
	}

	localDirs := map[string]string{
		"context":    dir,
		"dockerfile": dir,
	}
	frontendAttrs := map[string]string{
		"context":  "context",
		"filename": "Dockerfile",
	}
	if mrand.Intn(2) == 1 {
		frontendAttrs["no-cache"] = ""
	}
	solveOpt := client.SolveOpt{
		LocalDirs:     localDirs,
		FrontendAttrs: frontendAttrs,
	}

	_, err = c.Build(ctx, solveOpt, "buildkit-test", func(ctx context.Context, gw gwclient.Client) (*gwclient.Result, error) {
		buildRes, err := builder.Build(ctx, gw)
		if err != nil {
			return nil, errors.WithStack(err)
		}
		ref, err := buildRes.SingleRef()
		if err != nil {
			return nil, errors.WithStack(err)
		}
		res := gwclient.NewResult()
		res.SetRef(ref)
		return res, nil
	}, pw.Status())
	return err
}