package nix2 import ( "bytes" "encoding/json" "fmt" "os" "os/exec" "path/filepath" "github.com/hashicorp/nomad/helper/pluginutils/hclutils" ) const ( closureNix = ` { path }: let nixpkgs = builtins.getFlake "%s"; inherit (nixpkgs.legacyPackages.x86_64-linux) buildPackages; in buildPackages.closureInfo { rootPaths = builtins.storePath path; } ` ) func prepareNixPackages(taskDir string, packages []string, nixpkgs string) (hclutils.MapStrStr, error) { mounts := make(hclutils.MapStrStr) profileLink := filepath.Join(taskDir, "current-profile") profile, err := nixBuildProfile(packages, profileLink) if err != nil { return nil, fmt.Errorf("Build of the flakes failed: %v", err) } closureLink := filepath.Join(taskDir, "current-closure") closure, err := nixBuildClosure(profileLink, closureLink, nixpkgs) if err != nil { return nil, fmt.Errorf("Build of the flakes failed: %v", err) } mounts[profile] = profile if entries, err := os.ReadDir(profile); err != nil { return nil, fmt.Errorf("Couldn't read profile directory: %w", err) } else { for _, entry := range entries { if name := entry.Name(); name != "etc" { mounts[filepath.Join(profile, name)] = "/" + name continue } etcEntries, err := os.ReadDir(filepath.Join(profile, "etc")) if err != nil { return nil, fmt.Errorf("Couldn't read profile's /etc directory: %w", err) } for _, etcEntry := range etcEntries { etcName := etcEntry.Name() mounts[filepath.Join(profile, "etc", etcName)] = "/etc/" + etcName } } } requisites, err := nixRequisites(closure) if err != nil { return nil, fmt.Errorf("Couldn't determine flake requisites: %v", err) } for _, requisite := range requisites { mounts[requisite] = requisite } return mounts, nil } func nixBuildProfile(flakes []string, link string) (string, error) { cmd := exec.Command("nix", append( []string{ "--extra-experimental-features", "nix-command", "--extra-experimental-features", "flakes", "profile", "install", "--no-write-lock-file", "--profile", link}, flakes...)...) stderr := &bytes.Buffer{} cmd.Stderr = stderr if err := cmd.Run(); err != nil { return "", fmt.Errorf("%v failed: %s. Err: %v", cmd.Args, stderr.String(), err) } if target, err := os.Readlink(link); err == nil { return os.Readlink(filepath.Join(filepath.Dir(link), target)) } else { return "", err } } func nixBuildClosure(profile string, link string, nixpkgs string) (string, error) { cmd := exec.Command( "nix", "--extra-experimental-features", "nix-command", "--extra-experimental-features", "flakes", "build", "--out-link", link, "--expr", fmt.Sprintf(closureNix, nixpkgs), "--impure", "--no-write-lock-file", "--argstr", "path", profile) stderr := &bytes.Buffer{} cmd.Stderr = stderr if err := cmd.Run(); err != nil { return "", fmt.Errorf("%v failed: %s. Err: %v", cmd.Args, stderr.String(), err) } return os.Readlink(link) } type nixPathInfo struct { Path string `json:"path"` NarHash string `json:"narHash"` NarSize uint64 `json:"narSize"` References []string `json:"references"` Deriver string `json:"deriver"` RegistrationTime uint64 `json:"registrationTime"` Signatures []string `json:"signatures"` } func nixRequisites(path string) ([]string, error) { cmd := exec.Command( "nix", "--extra-experimental-features", "nix-command", "--extra-experimental-features", "flakes", "path-info", "--json", "--recursive", path) stdout := &bytes.Buffer{} cmd.Stdout = stdout stderr := &bytes.Buffer{} cmd.Stderr = stderr if err := cmd.Run(); err != nil { return nil, fmt.Errorf("%v failed: %s. Err: %v", cmd.Args, stderr.String(), err) } result := []*nixPathInfo{} if err := json.Unmarshal(stdout.Bytes(), &result); err != nil { return nil, err } requisites := []string{} for _, result := range result { requisites = append(requisites, result.Path) } return requisites, nil }