Add package initialization subcommand and package

pkg/codegen/pkg.go

@@ -0,0 +1,51 @@
+package codegen
+
+import (
+	"embed"
+	"fmt"
+	"os"
+	"os/exec"
+
+	. "git.offline-twitter.com/offline-labs/gas-stack/pkg/flowutils"
+)
+
+//go:embed "tpl"
+var tpl embed.FS
+
+type PkgOpts struct {
+	ModuleName string
+	DBFilename string
+	BinaryName string
+}
+
+func InitPkg(opts PkgOpts) {
+	// Run `go mod init`
+	fmt.Printf("Running...  `go mod init %s`\n", opts.ModuleName)
+	PanicIf(exec.Command("go", "mod", "init", opts.ModuleName).Run())
+
+	// Run `git init`, if required
+	if exec.Command("git", "status").Run() != nil {
+		// Not in a git repo yet; init one
+		fmt.Println("Running...  `git init`")
+		PanicIf(exec.Command("git", "init").Run())
+	}
+
+	// Create package structure
+	PanicIf(os.MkdirAll("pkg/db", 0o755))
+	PanicIf(os.MkdirAll("cmd", 0o755))
+	PanicIf(os.MkdirAll("doc", 0o755))
+	PanicIf(os.MkdirAll("sample_data", 0o755))
+
+	PanicIf(os.WriteFile("pkg/db/schema.sql", Must(tpl.ReadFile("tpl/schema.sql")), 0o664))
+
+	PanicIf(os.WriteFile("sample_data/mount.sh", Must(tpl.ReadFile("tpl/mount.sh")), 0o775))
+	PanicIf(os.WriteFile("sample_data/reset.sh", Must(tpl.ReadFile("tpl/reset.sh")), 0o775))
+	PanicIf(os.WriteFile("pkg/db/schema.sql", Must(tpl.ReadFile("tpl/schema.sql")), 0o664))
+
+	// TODO:
+	// - create `pkg/db/errors.go`
+	// - create `sample_data/seed.sql`
+	// - create `sample_data/data/`
+	// - create `.gitignore`
+	// - do something with `db_setup.go` (should go in Gas Stack `pkg/db`)
+}