From 48f2e9a2cbc35aefc11e14e8504f0090414291c8 Mon Sep 17 00:00:00 2001
From: Julien Dessaux
Date: Thu, 29 Aug 2024 20:22:56 +0200
Subject: feat(stdlib): added a basic borg client custom promise

---
 stdlib/backups/borg/borg-script-template     |  27 ++++++
 stdlib/backups/borg/client.go                | 123 +++++++++++++++++++++++++++
 stdlib/backups/borg/server.go                |   1 -
 stdlib/backups/borg/systemd-service-template |  15 ++++
 stdlib/backups/borg/systemd-timer-template   |   9 ++
 5 files changed, 174 insertions(+), 1 deletion(-)
 create mode 100644 stdlib/backups/borg/borg-script-template
 create mode 100644 stdlib/backups/borg/client.go
 create mode 100644 stdlib/backups/borg/systemd-service-template
 create mode 100644 stdlib/backups/borg/systemd-timer-template

diff --git a/stdlib/backups/borg/borg-script-template b/stdlib/backups/borg/borg-script-template
new file mode 100644
index 0000000..c09c297
--- /dev/null
+++ b/stdlib/backups/borg/borg-script-template
@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+on_exit() {
+  exit $?
+}
+trap on_exit EXIT
+
+archiveName="%s-%s-$(date +%%Y-%%m-%%dT%%H:%%M:%%S)"
+archiveSuffix=".failed"
+
+# Run borg init if the repo doesn't exist yet
+if ! borg list > /dev/null; then
+  borg init --encryption none
+fi
+(
+  borg create \
+    --compression auto,zstd \
+    "::${archiveName}${archiveSuffix}" \
+    '%s'
+)
+borg rename "::${archiveName}${archiveSuffix}" "${archiveName}"
+
+borg prune \
+  --keep-daily=14 --keep-monthly=3 --keep-weekly=4 \
+  --glob-archives '%s-%s*'
+borg compact
diff --git a/stdlib/backups/borg/client.go b/stdlib/backups/borg/client.go
new file mode 100644
index 0000000..a203ae2
--- /dev/null
+++ b/stdlib/backups/borg/client.go
@@ -0,0 +1,123 @@
+package borg
+
+import (
+	_ "embed"
+	"fmt"
+	"os"
+
+	"log/slog"
+	"path/filepath"
+
+	gonf "git.adyxax.org/adyxax/gonf/v2/pkg"
+)
+
+//go:embed borg-script-template
+var borg_script_template string
+
+//go:embed systemd-service-template
+var systemd_service_template string
+
+//go:embed systemd-timer-template
+var systemd_timer_template string
+
+type Job struct {
+	hostname   string
+	path       string
+	privateKey []byte
+}
+
+type BorgClient struct {
+	chain  []gonf.Promise
+	jobs   map[string]*Job // name -> privateKey
+	path   string
+	status gonf.Status
+}
+
+func (b *BorgClient) IfRepaired(p ...gonf.Promise) gonf.Promise {
+	b.chain = append(b.chain, p...)
+	return b
+}
+
+func (b *BorgClient) Promise() *BorgClient {
+	gonf.MakeCustomPromise(b).Promise()
+	return b
+}
+
+func (b *BorgClient) Resolve() {
+	b.status = gonf.KEPT
+	// borg package
+	switch installBorgPackage() {
+	case gonf.BROKEN:
+		b.status = gonf.BROKEN
+		return
+	case gonf.REPAIRED:
+		b.status = gonf.REPAIRED
+	}
+	// private key
+	rootDir := gonf.ModeUserGroup(0700, "root", "root")
+	rootRO := gonf.ModeUserGroup(0400, "root", "root")
+	rootRX := gonf.ModeUserGroup(0500, "root", "root")
+	gonf.Directory("/root/.cache/borg").DirectoriesPermissions(rootDir).Resolve()
+	gonf.Directory("/root/.config/borg").DirectoriesPermissions(rootDir).Resolve()
+	systemdSystemPath := "/etc/systemd/system/"
+	hostname, err := os.Hostname()
+	if err != nil {
+		slog.Error("Unable to find current hostname", "err", err)
+		hostname = "unknown"
+	}
+	for name, job := range b.jobs {
+		gonf.File(filepath.Join(b.path, fmt.Sprintf("%s.key", name))).
+			DirectoriesPermissions(rootDir).
+			Permissions(rootRO).Contents(job.privateKey).
+			Resolve()
+		gonf.File(filepath.Join(b.path, fmt.Sprintf("%s.sh", name))).
+			DirectoriesPermissions(rootDir).
+			Permissions(rootRX).Contents(fmt.Sprintf(borg_script_template,
+			hostname,
+			name,
+			job.path,
+			job.hostname, name)).
+			Resolve()
+		service_name := fmt.Sprintf("borgbackup-job-%s.service", name)
+		gonf.File(filepath.Join(systemdSystemPath, service_name)).
+			DirectoriesPermissions(rootDir).
+			Permissions(rootRO).Contents(fmt.Sprintf(systemd_service_template,
+			name,
+			job.hostname, name,
+			name,
+			name)).
+			Resolve()
+		timer_name := fmt.Sprintf("borgbackup-job-%s.timer", name)
+		gonf.File(filepath.Join(systemdSystemPath, timer_name)).
+			DirectoriesPermissions(rootDir).
+			Permissions(rootRO).Contents(fmt.Sprintf(systemd_timer_template, name)).
+			Resolve()
+		gonf.Service(timer_name).State("enabled", "started").Resolve()
+	}
+}
+
+func (b BorgClient) Status() gonf.Status {
+	return b.status
+}
+
+func Client() *BorgClient {
+	return &BorgClient{
+		chain:  nil,
+		jobs:   make(map[string]*Job),
+		path:   "/etc/borg/",
+		status: gonf.PROMISED,
+	}
+}
+
+func (b *BorgClient) Add(name string, path string, privateKey []byte, hostname string) *BorgClient {
+	if _, ok := b.jobs[name]; ok {
+		slog.Debug("Duplicate name for BorgClient", "name", name)
+		panic("Duplicate name for BorgClient")
+	}
+	b.jobs[name] = &Job{
+		hostname:   hostname,
+		path:       path,
+		privateKey: privateKey,
+	}
+	return b
+}
diff --git a/stdlib/backups/borg/server.go b/stdlib/backups/borg/server.go
index 2ef1d7e..4fe0e74 100644
--- a/stdlib/backups/borg/server.go
+++ b/stdlib/backups/borg/server.go
@@ -73,7 +73,6 @@ func (b *BorgServer) Resolve() {
 	case gonf.REPAIRED:
 		b.status = gonf.REPAIRED
 	}
-	// TODO init repositories? or let the borg client do it?
 }
 
 func (b BorgServer) Status() gonf.Status {
diff --git a/stdlib/backups/borg/systemd-service-template b/stdlib/backups/borg/systemd-service-template
new file mode 100644
index 0000000..336f6d2
--- /dev/null
+++ b/stdlib/backups/borg/systemd-service-template
@@ -0,0 +1,15 @@
+[Unit]
+Description=BorgBackup job %s
+
+[Service]
+Environment="BORG_REPO=ssh://borg@%s/srv/borg/%s"
+Environment="BORG_RSH=ssh -i /etc/borg/%s.key"
+CPUSchedulingPolicy=idle
+ExecStart=/etc/borg/%s.sh
+Group=root
+IOSchedulingClass=idle
+PrivateTmp=true
+ProtectSystem=strict
+ReadWritePaths=/root/.config/borg
+ReadWritePaths=/root/.cache/borg
+User=root
diff --git a/stdlib/backups/borg/systemd-timer-template b/stdlib/backups/borg/systemd-timer-template
new file mode 100644
index 0000000..218e5cc
--- /dev/null
+++ b/stdlib/backups/borg/systemd-timer-template
@@ -0,0 +1,9 @@
+[Unit]
+Description=BorgBackup job %s timer
+
+[Timer]
+OnCalendar=daily
+Persistent=false
+
+[Install]
+WantedBy=timers.target
-- 
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