Move symlinks setup to shared helper

This refactors how windowscross and mariner2 interact with symlinks and
adds actual symlinking to a shared helper so other targets can use it.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>

frontend/mariner2/handle_container.go

@@ -1,7 +1,6 @@
 package mariner2
 
 import (
- "bytes"
  "context"
  "fmt"
  "path/filepath"
@@ -143,51 +142,11 @@ rm -rf ` + rpmdbDir + `
  // The return value is the state representing the contents of the mounted directory after the commands are run
  rootfs := worker.AddMount(workPath, baseImg)
 
- if post := getImagePostInstall(spec, target); post != nil && len(post.Symlinks) > 0 {
+ if post := spec.GetImagePost(target); post != nil && len(post.Symlinks) > 0 {
  rootfs = worker.
- Run(dalec.WithConstraints(opts...), addImagePost(post, workPath)).
+ Run(dalec.WithConstraints(opts...), dalec.InstallPostSymlinks(post, workPath)).
  AddMount(workPath, rootfs)
  }
 
  return rootfs, nil
 }
-
-func getImagePostInstall(spec *dalec.Spec, targetKey string) *dalec.PostInstall {
- tgt, ok := spec.Targets[targetKey]
- if ok && tgt.Image != nil && tgt.Image.Post != nil {
- return tgt.Image.Post
- }
-
- if spec.Image == nil {
- return nil
- }
- return spec.Image.Post
-}
-
-func addImagePost(post *dalec.PostInstall, rootfsPath string) llb.RunOption {
- return runOptionFunc(func(ei *llb.ExecInfo) {
- if post == nil {
- return
- }
-
- if len(post.Symlinks) == 0 {
- return
- }
-
- buf := bytes.NewBuffer(nil)
- buf.WriteString("set -ex\n")
- fmt.Fprintf(buf, "cd %q\n", rootfsPath)
-
- for src, tgt := range post.Symlinks {
- fmt.Fprintf(buf, "ln -s %q %q\n", src, filepath.Join(rootfsPath, tgt.Path))
- }
- shArgs(buf.String()).SetRunOption(ei)
- dalec.ProgressGroup("Add post-install symlinks").SetRunOption(ei)
- })
-}
-
-type runOptionFunc func(*llb.ExecInfo)
-
-func (f runOptionFunc) SetRunOption(ei *llb.ExecInfo) {
- f(ei)
-}

frontend/windows/handle_container.go

@@ -68,7 +68,7 @@ func handleContainer(ctx context.Context, client gwclient.Client) (*gwclient.Res
 
  out := baseImage.
  File(llb.Copy(bin, "/", windowsSystemDir)).
- With(copySymlinks(spec.GetSymlinks(targetKey)))
+ With(copySymlinks(spec.GetImagePost(targetKey)))
 
  def, err := out.Marshal(ctx)
  if err != nil {
@@ -95,8 +95,13 @@ func handleContainer(ctx context.Context, client gwclient.Client) (*gwclient.Res
  })
 }
 
-func copySymlinks(lm map[string]dalec.SymlinkTarget) llb.StateOption {
+func copySymlinks(post *dalec.PostInstall) llb.StateOption {
  return func(s llb.State) llb.State {
+ if post == nil {
+ return s
+ }
+
+ lm := post.Symlinks
  if len(lm) == 0 {
  return s
  }

helpers.go

@@ -1,8 +1,11 @@
 package dalec
 
 import (
+ "bytes"
  "encoding/json"
+ "fmt"
  "path"
+ "path/filepath"
  "sort"
  "sync/atomic"
 
@@ -304,28 +307,53 @@ func (s *Spec) GetBuildDeps(targetKey string) []string {
 
 }
 
-func (s *Spec) GetSymlinks(target string) map[string]SymlinkTarget {
- lm := make(map[string]SymlinkTarget)
-
- if s.Image != nil && s.Image.Post != nil && s.Image.Post.Symlinks != nil {
- for k, v := range s.Image.Post.Symlinks {
- lm[k] = v
+func (s *Spec) GetImagePost(target string) *PostInstall {
+ img := s.Targets[target].Image
+ if img != nil {
+ if img.Post != nil {
+ return img.Post
  }
  }
 
- tgt, ok := s.Targets[target]
- if !ok {
- return lm
+ if s.Image != nil {
+ return s.Image.Post
  }
 
- if tgt.Image != nil && tgt.Image.Post != nil && tgt.Image.Post.Symlinks != nil {
- for k, v := range tgt.Image.Post.Symlinks {
- // target-specific values replace the ones in the spec toplevel
- lm[k] = v
+ return nil
+}
+
+// ShArgs returns a RunOption that runs the given command in a shell.
+func ShArgs(args string) llb.RunOption {
+ return llb.Args(append([]string{"sh", "-c"}, args))
+}
+
+// InstallPostSymlinks returns a RunOption that adds symlinks defined in the [PostInstall] underneath the provided rootfs path.
+func InstallPostSymlinks(post *PostInstall, rootfsPath string) llb.RunOption {
+ return runOptionFunc(func(ei *llb.ExecInfo) {
+ if post == nil {
+ return
  }
- }
 
- return lm
+ if len(post.Symlinks) == 0 {
+ return
+ }
+
+ llb.Dir(rootfsPath).SetRunOption(ei)
+
+ buf := bytes.NewBuffer(nil)
+ buf.WriteString("set -ex\n")
+
+ for src, tgt := range post.Symlinks {
+ fmt.Fprintf(buf, "ln -s %q %q\n", src, filepath.Join(rootfsPath, tgt.Path))
+ }
+
+ const name = "tmp.dalec.symlink.sh"
+ script := llb.Scratch().File(llb.Mkfile(name, 0o400, buf.Bytes()))
+
+ llb.AddMount(name, script, llb.SourcePath(name)).SetRunOption(ei)
+ llb.Args([]string{"/bin/sh", name}).SetRunOption(ei)
+ ProgressGroup("Add post-install symlinks").SetRunOption(ei)
+ })
 }
 
 func (s *Spec) GetSigner(targetKey string) (*Frontend, bool) {

test/windows_test.go

@@ -221,7 +221,8 @@ echo "$BAR" > bar.txt
  return nil, err
  }
 
- for srcPath, l := range spec.GetSymlinks("windowscross") {
+ post := spec.GetImagePost("windowscross")
+ for srcPath, l := range post.Symlinks {
  b1, err := ref.ReadFile(ctx, gwclient.ReadRequest{
  Filename: srcPath,
  })