Render a nix shell plus direnv config

internal/core/config.go

@@ -208,6 +208,10 @@ type Metadata struct {
 	URL string `yaml:"url"`
 }
 
+type NixConfig struct {
+	ExtraPackages []string `yaml:"extraPackages"`
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 // Helper functions
 

internal/nix/nix-shell.go

@@ -0,0 +1,69 @@
+package nix
+
+import (
+	"fmt"
+	"os"
+	"slices"
+	"strings"
+
+	"github.com/sapcc/go-bits/must"
+	"github.com/sapcc/go-makefile-maker/internal/core"
+	"github.com/sapcc/go-makefile-maker/internal/golang"
+)
+
+func RenderShell(cfg core.Configuration, sr golang.ScanResult, renderGoreleaserConfig bool) {
+	nixShellTemplate := `{ pkgs ? import <nixpkgs> { } }:
+
+with pkgs;
+
+mkShell {
+  nativeBuildInputs = [
+%s
+    # keep this line if you use bash
+    bashInteractive
+  ];
+}
+`
+
+	goVersionSlice := strings.Split(core.DefaultGoVersion, ".")
+	goPackage := fmt.Sprintf("go_%s_%s", goVersionSlice[0], goVersionSlice[1])
+	packages := []string{
+		goPackage,
+		"go-licence-detector",
+		"gotools # goimports",
+	}
+	if cfg.GolangciLint.CreateConfig {
+		packages = append(packages, "golangci-lint")
+	}
+	if renderGoreleaserConfig {
+		packages = append(packages, "goreleaser")
+	}
+	if sr.KubernetesController {
+		packages = append(packages, "kubernetes-controller-tools # controller-gen")
+		packages = append(packages, "setup-envtest")
+	}
+	if sr.UseGinkgo {
+		packages = append(packages, "ginkgo")
+	}
+	if sr.UsesPostgres {
+		packages = append(packages, "postgresql_"+core.DefaultPostgresVersion)
+	}
+	packages = append(packages, cfg.Nix.ExtraPackages...)
+
+	slices.Sort(packages)
+	packageList := ""
+	for _, pkg := range packages {
+		packageList += fmt.Sprintf("    %s\n", pkg)
+	}
+
+	nixShellFile := fmt.Sprintf(nixShellTemplate, packageList)
+	must.Succeed(os.WriteFile("shell.nix", []byte(nixShellFile), 0666))
+
+	must.Succeed(os.WriteFile(".envrc", []byte(`#!/usr/bin/env bash
+if type -P lorri &>/dev/null; then
+  eval "$(lorri direnv)"
+else
+  use nix
+fi
+`), 0666))
+}

main.go

@@ -34,6 +34,7 @@ import (
 	"github.com/sapcc/go-makefile-maker/internal/golangcilint"
 	"github.com/sapcc/go-makefile-maker/internal/goreleaser"
 	"github.com/sapcc/go-makefile-maker/internal/makefile"
+	"github.com/sapcc/go-makefile-maker/internal/nix"
 	"github.com/sapcc/go-makefile-maker/internal/renovate"
 )
 
@@ -62,6 +63,10 @@ func main() {
 	// Scan go.mod file for additional context information.
 	sr := golang.Scan()
 
+	renderGoreleaserConfig := (cfg.GoReleaser.CreateConfig == nil && cfg.GitHubWorkflow.Release.Enabled) || (cfg.GoReleaser.CreateConfig != nil && *cfg.GoReleaser.CreateConfig)
+
+	nix.RenderShell(cfg, sr, renderGoreleaserConfig)
+
 	// Render Makefile
 	if cfg.Makefile.Enabled == nil || *cfg.Makefile.Enabled {
 		for _, bin := range cfg.Binaries {
@@ -83,7 +88,7 @@ func main() {
 	}
 
 	// Render Goreleaser config file
-	if (cfg.GoReleaser.CreateConfig == nil && cfg.GitHubWorkflow.Release.Enabled) || (cfg.GoReleaser.CreateConfig != nil && *cfg.GoReleaser.CreateConfig) {
+	if renderGoreleaserConfig {
 		goreleaser.RenderConfig(cfg)
 	}