add shell directive

bob/bobfile/bobfile.go

@@ -65,8 +65,14 @@ type Bobfile struct {
 	// RTasks run tasks
 	RTasks bobrun.RunMap `yaml:"run"`
 
+	// Dependencies are nix packages used on a global scope.
+	// Mutually exclusive with Shell. ??Overwrites task based dependencies.??
 	Dependencies []string `yaml:"dependencies"`
 
+	// Shell specifies a shell.nix file as usually used by nix-shell.
+	// This is mutualy exclusive with Dependencies.
+	Shell string `yaml:"shell"`
+
 	// Nixpkgs specifies an optional nixpkgs source.
 	Nixpkgs string `yaml:"nixpkgs"`
 

bob/build.go

@@ -48,7 +48,7 @@ func (b *B) Build(ctx context.Context, taskName string) (err error) {
 }
 
 // AggregateWithNixDeps does aggregation together with evaluating nix dependecies.
-// Nic dependencies are altering a tasks input hash.
+// Nix dependencies are altering a tasks input hash.
 // Use this function for building `bob inspect` cmds.
 func (b *B) AggregateWithNixDeps(taskName string) (aggregate *bobfile.Bobfile, err error) {
 	defer errz.Recover(&err)

bob/nix-builder/nix_builder.go

@@ -2,8 +2,11 @@ package nixbuilder
 
 import (
 	"fmt"
+	"os"
 
+	"github.com/benchkram/bob/pkg/boblog"
 	"github.com/benchkram/bob/pkg/envutil"
+	"github.com/benchkram/bob/pkg/file"
 	"github.com/benchkram/errz"
 
 	"github.com/benchkram/bob/bob/bobfile"
@@ -88,6 +91,28 @@ func (n *NB) BuildNixDependencies(ag *bobfile.Bobfile, buildTasksInPipeline, run
 		return usererror.Wrap(fmt.Errorf("nix is not installed on your system. Get it from %s", nix.DownloadURl()))
 	}
 
+	if ag.Shell != "" {
+		boblog.Log.Info(fmt.Sprintf("using shell file %s, ignoring dependencies", ag.Shell))
+		// hash shell file
+		if !file.Exists(ag.Shell) {
+			return usererror.Wrap(fmt.Errorf("shell file %s does not exist", ag.Shell))
+		}
+
+		nixShellEnv, err := nix.NixShell(ag.Shell)
+		errz.Fatal(err)
+
+		f, err := os.ReadFile(ag.Shell)
+		errz.Fatal(err)
+		hash := envutil.Hash(string(f))
+		n.envStore[envutil.Hash(hash)] = nixShellEnv
+		for _, name := range buildTasksInPipeline {
+			t := ag.BTasks[name]
+			t.SetEnvID(envutil.Hash(hash))
+			ag.BTasks[name] = t
+		}
+		return nil
+	}
+
 	// Resolve nix storePaths from dependencies
 	// and rewrite the affected tasks.
 	for _, name := range buildTasksInPipeline {
@@ -153,7 +178,6 @@ func (n *NB) BuildEnvironment(deps []nix.Dependency, nixpkgs string) (_ []string
 	return nix.BuildEnvironment(deps, nixpkgs, n.cache, n.shellCache)
 }
 
-// Clean removes all cached nix dependencies
 func (n *NB) Clean() (err error) {
 	return n.cache.Clean()
 }

pkg/nix/nix.go

@@ -336,3 +336,43 @@ func HashDependencies(deps []Dependency) (_ string, err error) {
 	}
 	return string(h.Sum()), nil
 }
+
+// NixShell returns the environment of a nix-shell command
+func NixShell(path string) ([]string, error) {
+
+	args := []string{}
+	for _, envKey := range global.EnvWhitelist {
+		if _, exists := os.LookupEnv(envKey); exists {
+			args = append(args, []string{"--keep", envKey}...)
+		}
+	}
+	args = append(args, []string{"--pure", "--command", "env"}...)
+	args = append(args, path)
+	cmd := exec.Command("nix-shell", args...)
+
+	var out bytes.Buffer
+	var errBuf bytes.Buffer
+	cmd.Stdout = &out
+	cmd.Stderr = &errBuf
+
+	env := strings.Split(out.String(), "\n")
+	err := cmd.Run()
+	if err != nil {
+		return nil, prepareRunError(err, cmd.String(), errBuf)
+	}
+
+	// if NIX_SSL_CERT_FILE && SSL_CERT_FILE are set to /no-cert-file.crt unset them
+	var clearedEnv []string
+	for _, e := range env {
+		pair := strings.SplitN(e, "=", 2)
+		if pair[0] == "NIX_SSL_CERT_FILE" && pair[1] == "/no-cert-file.crt" {
+			continue
+		}
+		if pair[0] == "SSL_CERT_FILE" && pair[1] == "/no-cert-file.crt" {
+			continue
+		}
+		clearedEnv = append(clearedEnv, e)
+	}
+
+	return clearedEnv, nil
+}