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package file
import (
"bytes"
"fmt"
"log"
"os"
"os/user"
"strconv"
"strings"
"text/template"
"codeberg.org/snonux/gonf/internal/resource"
"codeberg.org/snonux/gonf/internal/resource/opt"
)
type File struct {
resource resource.Resource
path string
content string
source string // bare path, no "source://" prefix
user string
group string
mode os.FileMode
absent bool
}
// SetContent implements opt.Contented. Setting literal content clears any
// previously configured source, as the two are mutually exclusive.
func (f *File) SetContent(content string) {
f.content = content
f.source = ""
}
// SetSource implements opt.Sourced. Setting a source clears any previously
// configured literal content, as the two are mutually exclusive.
func (f *File) SetSource(source string) {
f.source = source
f.content = ""
}
// SetOwner implements opt.Owner.
func (f *File) SetOwner(user string) { f.user = user }
// SetGroup implements opt.Grouped.
func (f *File) SetGroup(group string) { f.group = group }
// SetMode implements opt.Moded.
func (f *File) SetMode(mode os.FileMode) { f.mode = mode }
// SetAbsent implements opt.Absentable.
func (f *File) SetAbsent() { f.absent = true }
func build(path string, opts ...opt.Option) (*File, error) {
curr, err := user.Current()
if err != nil {
return nil, fmt.Errorf("failed to get current user for default: %w", err)
}
f := &File{
path: path,
mode: 0o640,
user: curr.Username,
group: curr.Gid,
}
for _, o := range opts {
o(f)
}
return f, nil
}
// apply performs the idempotent OS work for f without registering a
// resource.
func (f *File) apply() error {
if f.absent {
return ensureAbsent(f.targetPath())
}
finalPath, content, err := f.resolve()
if err != nil {
return fmt.Errorf("failed to resolve content for %s: %w", f.path, err)
}
return f.ensureFile(finalPath, content)
}
// targetPath returns the actual on-disk path f writes to. It strips a
// trailing ".tmpl" suffix from the caller-given path whenever templating was
// triggered by a ".tmpl"-suffixed source, so a source foo.conf.tmpl never
// leaves a foo.conf.tmpl behind on disk — whether that source is written via
// a direct Have/Ensure call or delegated to from a directory source-tree
// copy, since both routes go through this same function.
func (f *File) targetPath() string {
if strings.HasSuffix(f.source, ".tmpl") {
return strings.TrimSuffix(f.path, ".tmpl")
}
return f.path
}
// shouldRenderTemplate reports whether content should be rendered through
// text/template: either the destination path or the source path ends in
// ".tmpl".
func (f *File) shouldRenderTemplate() bool {
return strings.HasSuffix(f.path, ".tmpl") || strings.HasSuffix(f.source, ".tmpl")
}
// resolve reads f's content (from source or literal content), renders it as
// a template if applicable, and returns the final on-disk path alongside the
// resulting bytes. Param is always the bare source path when source-based
// (never a "source://"-prefixed string), or the literal content when
// content-based — one definition used by both the single-file path and by
// dir's per-file delegation.
func (f *File) resolve() (string, []byte, error) {
var content []byte
param := f.content
if f.source != "" {
data, err := os.ReadFile(f.source)
if err != nil {
return "", nil, fmt.Errorf("failed to read source file %s: %w", f.source, err)
}
content = data
param = f.source
} else {
content = []byte(f.content)
}
if f.shouldRenderTemplate() {
rendered, err := f.applyTemplateToContent(content, param)
if err != nil {
return "", nil, err
}
content = rendered
}
return f.targetPath(), content, nil
}
func (f *File) applyTemplateToContent(content []byte, param string) ([]byte, error) {
data := make(map[string]string)
for _, env := range os.Environ() {
pair := strings.SplitN(env, "=", 2)
if len(pair) == 2 {
data[pair[0]] = pair[1]
}
}
data["Param"] = param
tmpl, err := template.New("resource").Parse(string(content))
if err != nil {
return nil, fmt.Errorf("template parse error: %w", err)
}
var buf bytes.Buffer
if err := tmpl.Execute(&buf, data); err != nil {
return nil, fmt.Errorf("template execute error: %w", err)
}
return buf.Bytes(), nil
}
func (f *File) applyAttributesTo(path string) error {
if err := os.Chmod(path, f.mode); err != nil {
return fmt.Errorf("failed to chmod %s to %v: %w", path, f.mode, err)
}
log.Printf("set mode %v for %s", f.mode, path)
uid, gid := -1, -1
if f.user != "" {
u, err := user.Lookup(f.user)
if err != nil {
return fmt.Errorf("failed to lookup user %s: %w", f.user, err)
}
uid, _ = strconv.Atoi(u.Uid)
}
if f.group != "" {
gidInt, err := strconv.Atoi(f.group)
if err != nil {
return fmt.Errorf("group must be numeric for now: %s", f.group)
}
gid = gidInt
}
if err := os.Chown(path, uid, gid); err != nil {
return fmt.Errorf("failed to chown %s to %s:%s: %w", path, f.user, f.group, err)
}
log.Printf("set owner %s:%s for %s", f.user, f.group, path)
return nil
}
func ensureAbsent(path string) error {
log.Printf("ensuring absent: %s", path)
if err := os.Remove(path); err != nil {
if os.IsNotExist(err) {
log.Printf("%s already absent", path)
return nil
}
return fmt.Errorf("failed to remove %s: %w", path, err)
}
log.Printf("removed %s", path)
return nil
}
// Ensure builds and applies the file resource described by opts, without
// registering it. Used by other resource packages (e.g. dir) to write an
// individual file without it becoming its own top-level resource.
func Ensure(path string, opts ...opt.Option) error {
_, err := build(path, opts...)
return err
}
func Have(path string, opts ...opt.Option) resource.Resource {
f, err := build(path, opts...)
if err != nil {
log.Fatalf("failed to apply file resource %s: %v", path, err)
}
f.resource = resource.Register("File", f.targetPath(),
resource.ApplierFunc(func() error { return f.apply() }))
return f.resource
}
func Absent(path string, opts ...opt.Option) resource.Resource {
opts = append(opts, opt.IsAbsent())
return Have(path, opts...)
}
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