Files
Maestro/src/lib/instance/instance.go
T

95 lines
3.1 KiB
Go

// Copyright (C) 2026 Dcntrlized
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
// Package instance holds the instance's public identity: a small, self-
// contained file at the data root that answers "who am I" for the hub app's
// public profile (hub-app theme M1) and, later, federation attestation.
package instance
import (
"encoding/json"
"fmt"
"os"
"path/filepath"
)
// Identity is the instance's user-visible self-description. Name falls back to
// DCNTRLIZED_INSTANCE_NAME and then the hostname when instance.json is absent;
// Title and Description are optional and only ever come from the file.
type Identity struct {
Name string `json:"name"`
Title string `json:"title,omitempty"`
Description string `json:"description,omitempty"`
}
// Path returns the identity file location for the given data root.
func Path(dataRoot string) string {
return filepath.Join(dataRoot, "instance.json")
}
// Load resolves the instance identity: instance.json when present, else
// DCNTRLIZED_INSTANCE_NAME, else os.Hostname(). Read-on-demand by design —
// no daemon state, so an edited file shows up on the next request.
func Load(dataRoot string) Identity {
id := defaultIdentity()
if data, err := os.ReadFile(Path(dataRoot)); err == nil {
var fromFile Identity
if json.Unmarshal(data, &fromFile) == nil && fromFile.Name != "" {
if fromFile.Title != "" {
id.Title = fromFile.Title
}
if fromFile.Description != "" {
id.Description = fromFile.Description
}
id.Name = fromFile.Name
}
}
return id
}
// Save atomically writes the identity file (tmp + rename), chmod 600 like the
// rest of Maestro's file stores. The owner-gated edit endpoint that uses this
// lands with the federation theme; the helper exists so both callers share one
// write path.
func Save(dataRoot string, id Identity) error {
if id.Name == "" {
return fmt.Errorf("instance name must not be empty")
}
data, err := json.MarshalIndent(id, "", " ")
if err != nil {
return fmt.Errorf("marshal instance identity: %w", err)
}
path := Path(dataRoot)
tmp := path + ".tmp"
if err := os.WriteFile(tmp, append(data, '\n'), 0o600); err != nil {
return fmt.Errorf("write instance identity: %w", err)
}
if err := os.Rename(tmp, path); err != nil {
return fmt.Errorf("replace instance identity: %w", err)
}
return nil
}
func defaultIdentity() Identity {
name := os.Getenv("DCNTRLIZED_INSTANCE_NAME")
if name == "" {
if host, err := os.Hostname(); err == nil {
name = host
}
}
return Identity{Name: name}
}