From deec04bf0d7425a8d0b9fc9db59c30e64a883b64 Mon Sep 17 00:00:00 2001
From: Ian Fijolek <ian@iamthefij.com>
Date: Mon, 19 Dec 2022 09:50:44 -0800
Subject: [PATCH] Allow setting of global defaults for some values

This helps with reducing redundant config.

Note: There is no default for `alert_every` because the zero value has a
meaning and cannot be interpreted as an omission.
---
 README.md                            |  3 +++
 config.go                            | 24 +++++++++++++++++++++---
 config_test.go                       |  1 +
 test/valid-config-default-values.yml | 12 ++++++++++++
 4 files changed, 37 insertions(+), 3 deletions(-)
 create mode 100644 test/valid-config-default-values.yml

diff --git a/README.md b/README.md
index 4db92d7..4e0a524 100644
--- a/README.md
+++ b/README.md
@@ -55,6 +55,9 @@ The global configurations are:
 |key|value|
 |---|---|
 |`check_interval`|Maximum frequency to run checks for each monitor as duration, eg. 1m2s.|
+|`default_alert_after`|A default value used as an `alert_after` value for a monitor if not specified or 0.|
+|`default_alert_down`|Default down alerts to used by a monitor in case none are provided.|
+|`default_alert_up`|Default up alerts to used by a monitor in case none are provided.|
 |`monitors`|List of all monitors. Detailed description below|
 |`alerts`|List of all alerts. Detailed description below|
 
diff --git a/config.go b/config.go
index a389b2b..d4b5bbb 100644
--- a/config.go
+++ b/config.go
@@ -13,9 +13,12 @@ var errInvalidConfig = errors.New("Invalid configuration")
 
 // Config type is contains all provided user configuration
 type Config struct {
-	CheckInterval SecondsOrDuration `yaml:"check_interval"`
-	Monitors      []*Monitor
-	Alerts        map[string]*Alert
+	CheckInterval     SecondsOrDuration `yaml:"check_interval"`
+	DefaultAlertAfter int16             `yaml:"default_alert_after"`
+	DefaultAlertDown  []string          `yaml:"default_alert_down"`
+	DefaultAlertUp    []string          `yaml:"default_alert_up"`
+	Monitors          []*Monitor
+	Alerts            map[string]*Alert
 }
 
 // CommandOrShell type wraps a string or list of strings
@@ -135,8 +138,23 @@ func (config Config) IsValid() (isValid bool) {
 
 // Init performs extra initialization on top of loading the config from file
 func (config *Config) Init() (err error) {
+	for _, monitor := range config.Monitors {
+		if monitor.AlertAfter == 0 && config.DefaultAlertAfter > 0 {
+			monitor.AlertAfter = config.DefaultAlertAfter
+		}
+
+		if len(monitor.AlertDown) == 0 && len(config.DefaultAlertDown) > 0 {
+			monitor.AlertDown = config.DefaultAlertDown
+		}
+
+		if len(monitor.AlertUp) == 0 && len(config.DefaultAlertUp) > 0 {
+			monitor.AlertUp = config.DefaultAlertUp
+		}
+	}
+
 	for name, alert := range config.Alerts {
 		alert.Name = name
+
 		if err = alert.BuildTemplates(); err != nil {
 			return
 		}
diff --git a/config_test.go b/config_test.go
index 6945b40..1f023c7 100644
--- a/config_test.go
+++ b/config_test.go
@@ -14,6 +14,7 @@ func TestLoadConfig(t *testing.T) {
 		pyCompat   bool
 	}{
 		{"./test/valid-config.yml", false, "Valid config file", false},
+		{"./test/valid-config-default-values.yml", false, "Valid config file with default values", false},
 		{"./test/valid-default-log-alert.yml", false, "Valid config file with default log alert PyCompat", true},
 		{"./test/valid-default-log-alert.yml", true, "Invalid config file no log alert", false},
 		{"./test/does-not-exist", true, "Invalid config path", false},
diff --git a/test/valid-config-default-values.yml b/test/valid-config-default-values.yml
new file mode 100644
index 0000000..f25dd2d
--- /dev/null
+++ b/test/valid-config-default-values.yml
@@ -0,0 +1,12 @@
+---
+check_interval: 1
+default_alert_down: ["log_command"]
+default_alert_after: 1
+
+monitors:
+  - name: Command
+    command: ["echo", "$PATH"]
+
+alerts:
+  log_command:
+    command: ["echo", "regular", '"command!!!"', "{{.MonitorName}}"]