From 7229ee22b48e6e065a572d31caeb447f78c16734 Mon Sep 17 00:00:00 2001
From: Julian Brost <julian.brost@icinga.com>
Date: Thu, 20 Jun 2024 13:29:02 +0200
Subject: [PATCH] Allow setting libexecdir (/usr/libexec) from build flags

This allows building packages with different values of libexecdir with the
daemon binary automatically adapting the channel plugin dir to it, i.e. so
there is no need to specify it in the config file.

This is relevant for Suse where %{_libexecdir} expands to /usr/lib instead.
---
 Makefile                  |  6 +++++-
 config.example.yml        |  2 +-
 internal/daemon/config.go | 13 ++++++++++++-
 internal/paths.go         |  6 ++++++
 4 files changed, 24 insertions(+), 3 deletions(-)
 create mode 100644 internal/paths.go

diff --git a/Makefile b/Makefile
index aefb4599..3e7201c6 100644
--- a/Makefile
+++ b/Makefile
@@ -10,9 +10,13 @@ libexecdir ?= $(prefix)/libexec
 datadir    ?= $(prefix)/share
 sysconfdir ?= /etc
 
+all: pkg = github.com/icinga/icinga-notifications/internal
 all:
 	mkdir -p build
-	go build -o build/ ./cmd/icinga-notifications
+	go build \
+		-o build/ \
+		-ldflags "-X '$(pkg).LibExecDir=$(libexecdir)'" \
+		./cmd/icinga-notifications
 	go build -o build/channel/ ./cmd/channel/...
 
 test:
diff --git a/config.example.yml b/config.example.yml
index 8b800d05..3d126a63 100644
--- a/config.example.yml
+++ b/config.example.yml
@@ -7,7 +7,7 @@
 #debug-password: "put-something-secret-here"
 
 icingaweb2-url: http://localhost/icingaweb2/
-channel-plugin-dir: /usr/libexec/icinga-notifications/channel
+#channel-plugin-dir: /usr/libexec/icinga-notifications/channel
 api-timeout: 1m
 
 database:
diff --git a/internal/daemon/config.go b/internal/daemon/config.go
index 309f53b5..e612cc6a 100644
--- a/internal/daemon/config.go
+++ b/internal/daemon/config.go
@@ -6,6 +6,7 @@ import (
 	"github.com/goccy/go-yaml"
 	"github.com/icinga/icinga-go-library/database"
 	"github.com/icinga/icinga-go-library/logging"
+	"github.com/icinga/icinga-notifications/internal"
 	"os"
 	"time"
 )
@@ -13,13 +14,23 @@ import (
 type ConfigFile struct {
 	Listen           string          `yaml:"listen" default:"localhost:5680"`
 	DebugPassword    string          `yaml:"debug-password"`
-	ChannelPluginDir string          `yaml:"channel-plugin-dir" default:"/usr/libexec/icinga-notifications/channel"`
+	ChannelPluginDir string          `yaml:"channel-plugin-dir"`
 	ApiTimeout       time.Duration   `yaml:"api-timeout" default:"1m"`
 	Icingaweb2URL    string          `yaml:"icingaweb2-url"`
 	Database         database.Config `yaml:"database"`
 	Logging          logging.Config  `yaml:"logging"`
 }
 
+// SetDefaults implements the defaults.Setter interface.
+func (c *ConfigFile) SetDefaults() {
+	if defaults.CanUpdate(c.ChannelPluginDir) {
+		c.ChannelPluginDir = internal.LibExecDir + "/icinga-notifications/channel"
+	}
+}
+
+// Assert interface compliance.
+var _ defaults.Setter = (*ConfigFile)(nil)
+
 // config holds the configuration state as a singleton. It is used from LoadConfig and Config
 var config *ConfigFile
 
diff --git a/internal/paths.go b/internal/paths.go
new file mode 100644
index 00000000..d7076f71
--- /dev/null
+++ b/internal/paths.go
@@ -0,0 +1,6 @@
+package internal
+
+// This variable exists to allow overwriting the path using `go build -ldflags "-X ...", see Makefile.
+var (
+	LibExecDir = "/usr/libexec"
+)