From 289d877e414336e3dcf2f44f84ea9dae073a0372 Mon Sep 17 00:00:00 2001
From: Bastien Riviere <me@babariviere.com>
Date: Fri, 1 Sep 2023 17:53:47 +0200
Subject: [PATCH] feat: add config format

---
 config.example.scfg |  19 +++++
 config/config.go    | 173 ++++++++++++++++++++++++++++++++++++++++++++
 go.mod              |   2 +
 go.sum              |   3 +
 4 files changed, 197 insertions(+)
 create mode 100644 config.example.scfg
 create mode 100644 config/config.go
 create mode 100644 go.sum

diff --git a/config.example.scfg b/config.example.scfg
new file mode 100644
index 0000000..cae9030
--- /dev/null
+++ b/config.example.scfg
@@ -0,0 +1,19 @@
+# listening address for the http server
+http-address 0.0.0.0:8080
+log-level info
+# text or json
+log-format text
+
+ntfy {
+  server "https://ntfy.sh"
+}
+
+handler "/flux" {
+  type "flux"
+  topic "/flux"
+}
+
+# handler "/alertmanager" {
+#   type "alertmanager"
+#   topic "/infra"
+# }
diff --git a/config/config.go b/config/config.go
new file mode 100644
index 0000000..45a35f2
--- /dev/null
+++ b/config/config.go
@@ -0,0 +1,173 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+
+	"git.sr.ht/~emersion/go-scfg"
+)
+
+type HandlerType int
+
+const (
+	HandlerNone HandlerType = iota
+	HandlerFlux
+)
+
+type LogFormat int
+
+const (
+	LogFormatText LogFormat = iota
+	LogFormatJson
+)
+
+type Config struct {
+	HTTPAddress string
+	LogLevel    string
+	LogFormat   LogFormat
+
+	Ntfy     ntfy
+	Handlers map[string]handler
+}
+
+type ntfy struct {
+	Server       string
+	DefaultTopic string
+}
+
+func (n *ntfy) readConfig(cfg scfg.Block) error {
+	if err := readString(cfg, "server", &n.Server); err != nil {
+		return err
+	}
+
+	return readString(cfg, "default-topic", &n.DefaultTopic)
+}
+
+type handler struct {
+	Type  HandlerType
+	Topic string
+}
+
+func (h *handler) readConfig(cfg scfg.Block) error {
+	var err error
+	if h.Type, err = readHandlerType(cfg.Get("type")); err != nil {
+		return err
+	}
+
+	return readStringRequired(cfg, "topic", &h.Topic)
+}
+
+func ReadConfig(path string) (Config, error) {
+	cfg, err := scfg.Load(path)
+	if err != nil {
+		return Config{}, err
+	}
+
+	config := Config{
+		HTTPAddress: "127.0.0.1:8080",
+		LogLevel:    "info",
+		LogFormat:   LogFormatText,
+
+		Ntfy: ntfy{
+			Server: "https://ntfy.sh",
+		},
+		Handlers: make(map[string]handler),
+	}
+
+	if err := readString(cfg, "http-address", &config.HTTPAddress); err != nil {
+		return config, err
+	}
+
+	if err := readString(cfg, "log-level", &config.LogLevel); err != nil {
+		return config, err
+	}
+
+	if err := readLogFormat(cfg, "log-format", &config.LogFormat); err != nil {
+		return config, err
+	}
+
+	d := cfg.Get("ntfy")
+	if d != nil {
+		if err := config.Ntfy.readConfig(d.Children); err != nil {
+			return config, err
+		}
+	}
+
+	ds := cfg.GetAll("handler")
+	for _, d := range ds {
+		var key string
+		if err := d.ParseParams(&key); err != nil {
+			return config, err
+		}
+
+		var h handler
+		if err := h.readConfig(d.Children); err != nil {
+			return config, err
+		}
+
+		config.Handlers[key] = h
+	}
+
+	for _, block := range cfg {
+		fmt.Printf("%+v\n", block)
+
+	}
+	return config, nil
+}
+
+func readHandlerType(d *scfg.Directive) (HandlerType, error) {
+	if d == nil {
+		return HandlerNone, errors.New("handler.type is missing")
+	}
+
+	var ty string
+
+	if err := d.ParseParams(&ty); err != nil {
+		return HandlerNone, err
+	}
+
+	switch ty {
+	case "flux":
+		return HandlerFlux, nil
+	default:
+		return HandlerNone, fmt.Errorf("invalid handler type %q", ty)
+	}
+}
+
+func readLogFormat(cfg scfg.Block, key string, val *LogFormat) error {
+	d := cfg.Get(key)
+	if d == nil {
+		return nil
+	}
+
+	var format string
+	if err := d.ParseParams(&format); err != nil {
+		return err
+	}
+
+	switch format {
+	case "text":
+		*val = LogFormatText
+	case "json":
+		*val = LogFormatJson
+	default:
+		return fmt.Errorf("invalid log format %q", format)
+	}
+	return nil
+}
+
+func readString(cfg scfg.Block, key string, val *string) error {
+	d := cfg.Get(key)
+	if d != nil {
+		return d.ParseParams(val)
+	}
+	return nil
+}
+
+func readStringRequired(cfg scfg.Block, key string, val *string) error {
+	d := cfg.Get(key)
+	if d != nil {
+		return d.ParseParams(val)
+	}
+	return fmt.Errorf("missing key %q", key)
+}
diff --git a/go.mod b/go.mod
index d1cdf88..9fdda8d 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,5 @@
 module forge.babariviere.com/babariviere/ntfy-bridge
 
 go 1.20
+
+require git.sr.ht/~emersion/go-scfg v0.0.0-20230828131541-76adf4aeafd7
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..db251b4
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,3 @@
+git.sr.ht/~emersion/go-scfg v0.0.0-20230828131541-76adf4aeafd7 h1:Cxfw56Srn4yJ2qPUuUvG9qQoQl45U7SsCjSmeTN63Xw=
+git.sr.ht/~emersion/go-scfg v0.0.0-20230828131541-76adf4aeafd7/go.mod h1:ybgvEJTIx5XbaspSviB3KNa6OdPmAZqDoSud7z8fFlw=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=