Switch to config-file, support multiple notifiers of same type

Signed-off-by: Knut Ahlers <knut@ahlers.me>

.gitignore

@@ -1 +1,2 @@
 birthday-notifier
+config.yaml

README.md

@@ -17,30 +17,97 @@ Hosted somewhere it's always running and configured properly and birthday notifi
 ```console
 # birthday-notifier --help
 Usage of birthday-notifier:
-      --fetch-interval duration       How often to fetch birthdays from CardDAV (default 1h0m0s)
+  -c, --config string      Configuration file path (default "config.yaml")
-      --log-level string              Log level (debug, info, warn, error, fatal) (default "info")
+      --log-level string   Log level (debug, info, warn, error, fatal) (default "info")
-      --notify-days-in-advance ints   Send notification X days before birthday (default [1])
+      --version            Prints current version and exits
-      --notify-via strings            How to send the notification (log, pushover, slack) (default [log])
-      --version                       Prints current version and exits
-      --webdav-base-url string        Webdav server to connect to
-      --webdav-pass string            Password for the Webdav user
-      --webdav-principal string       Principal format to fetch the addressbooks for (%s will be replaced with the webdav-user) (default "principals/users/%s")
-      --webdav-user string            Username for Webdav login
 ```
 
-For Nextcloud leave the principal format the default, for other systems you might need to adjust it.
+## Configuration
 
-To adjust the notification text see the template in [`pkg/formatter/formatter.go`](./pkg/formatter/formatter.go) and provide your own as `NOTIFICATION_TEMPLATE` environment variable.
+```yaml
+# Specify days before the actual birthday to send advance notifications
+# i.e. to buy gifts or something. Default is to send only on the actual
+# birthday itself.
+notifyDaysInAdvance: [ 1 ]
 
-### Notifier configuration
+# Configure how to notify you when there is a birthday pending / today.
+# Each entry consists of a type and the settings for that kind of
+# notifier. For settings and available types see below.
+notifiers:
+  - type: slack
+    settings:
+      webhook: https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX
 
-- **`log`** - Just sends the notification to the console logs, no configuration available
+# Specify your own template for the notification text. The default is
-- **`pushover`** - Send notification via [Pushover](https://pushover.net)
+# shown below and whould yield something like this:
-  - `PUSHOVER_API_TOKEN` - Token for the App you've created in the Pushover Dashboard
+#
-  - `PUSHOVER_USER_KEY` - Token for the User to send the notification to
+# Ava has their birthday on Wed, 13 Mar. They are turning 27.
-  - `PUSHOVER_SOUND` - (Optional) Specify a sound to use
+template: >-
-- **`slack`** - Send notification through Slack(-compatible) webhook
+  {{ .contact | getName }} has their birthday
-  - `SLACK_WEBHOOK` - Webhook URL (i.e. `https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX` or `https://discord.com/api/webhooks/00000/XXXXX/slack`)
+  {{ if .when | isToday -}} today {{- else -}}
-  - `SLACK_CHANNEL` - (Optional) Specify the channel to send to
+  on {{ (.when | projectToNext).Format "Mon, 02 Jan" }} {{- end }}.
-  - `SLACK_ICON_EMOJI` - (Optional) Emoji to use as user icon
+  {{ if gt .when.Year 1 -}}They are turning {{ .when | getAge }}.{{- end }}
-  - `SLACK_USERNAME` - (Optional) Overwrite the hooks username
+
+# Configure how to connect to the CardDAV addressbooks inside the
+# webdav server
+webdav:
+  # Base-URL for the webdav server (example for Nextcloud)
+  baseURL: https://my-nextcloud.example.com/remote.php/dav/
+  # How often to fetch new birthdays (default: 1h)
+  fetchInterval: 1h
+  # Password for the user
+  pass: 'my super secret password'
+  # Principal format for the webdav server (default as below is valid
+  # for Nextcloud instances): `%s` will be replaced with the value of
+  # the user field below.
+  principal: 'principals/users/%s'
+  # Username for the login to the webdav server
+  user: 'my.username'
+```
+
+### Notifiers
+
+#### `log`
+
+Just sends the notification to the console logs
+
+```yaml
+notifiers:
+  - type: log
+    # No settings for this one
+```
+
+#### `pushover`
+
+Send notification via [Pushover](https://pushover.net)
+
+```yaml
+notifiers:
+  - type: pushover
+    settings:
+      # Token for the App you've created in the Pushover Dashboard
+      apiToken: '...' 
+      # Token for the User to send the notification to
+      userKey: '...'
+      # (Optional) Specify a sound to use
+      sound: ''
+```
+
+#### `slack`
+
+Send notification through Slack(-compatible) webhook
+
+```yaml
+notifiers:
+  - type: slack
+    settings:
+      # Webhook URL (i.e. `https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX`
+      # or `https://discord.com/api/webhooks/00000/XXXXX/slack`)
+      webhook: 'https://...'
+      # (Optional) Specify the channel to send to
+      channel: ''
+      # (Optional) Emoji to use as user icon
+      iconEmoji: ''
+      # (Optional) Overwrite the hooks username\
+      username: ''
+```

caldav.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"time"
 
+	"git.luzifer.io/luzifer/birthday-notifier/pkg/config"
 	"git.luzifer.io/luzifer/birthday-notifier/pkg/dateutil"
 	"github.com/emersion/go-vcard"
 	"github.com/emersion/go-webdav"
@@ -20,10 +21,10 @@ type (
 	}
 )
 
-func fetchBirthdays() (birthdays []birthdayEntry, err error) {
+func fetchBirthdays(webdavConfig config.WebdavConfig) (birthdays []birthdayEntry, err error) {
 	client, err := carddav.NewClient(
-		webdav.HTTPClientWithBasicAuth(http.DefaultClient, cfg.WebdavUser, cfg.WebdavPass),
+		webdav.HTTPClientWithBasicAuth(http.DefaultClient, webdavConfig.User, webdavConfig.Pass),
-		cfg.WebdavBaseURL,
+		webdavConfig.BaseURL,
 	)
 	if err != nil {
 		return nil, fmt.Errorf("creating carddav client: %w", err)
@@ -31,7 +32,7 @@ func fetchBirthdays() (birthdays []birthdayEntry, err error) {
 
 	homeSet, err := client.FindAddressBookHomeSet(
 		context.Background(),
-		fmt.Sprintf(cfg.WebdavPrincipal, cfg.WebdavUser),
+		fmt.Sprintf(webdavConfig.Principal, webdavConfig.User),
 	)
 	if err != nil {
 		return nil, fmt.Errorf("getting addressbook-home-set: %w", err)

go.mod

@@ -3,6 +3,7 @@ module git.luzifer.io/luzifer/birthday-notifier
 go 1.22.0
 
 require (
+	github.com/Luzifer/go_helpers/v2 v2.23.0
 	github.com/Luzifer/rconfig/v2 v2.5.0
 	github.com/emersion/go-vcard v0.0.0-20230815062825-8fda7d206ec9
 	github.com/emersion/go-webdav v0.5.0
@@ -11,13 +12,13 @@ require (
 	github.com/robfig/cron/v3 v3.0.1
 	github.com/sirupsen/logrus v1.9.3
 	github.com/stretchr/testify v1.8.4
+	gopkg.in/yaml.v3 v3.0.1
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
-	golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 // indirect
+	golang.org/x/sys v0.18.0 // indirect
 	gopkg.in/validator.v2 v2.0.1 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -1,3 +1,5 @@
+github.com/Luzifer/go_helpers/v2 v2.23.0 h1:VowDwOCl6nOt+GVqKUX/do6a94pEeqNTRHb29MsoGX4=
+github.com/Luzifer/go_helpers/v2 v2.23.0/go.mod h1:BSGkJ/dxqs7AxsfZt8zjJb4R6YB5dONS+/ad7foLUrk=
 github.com/Luzifer/rconfig/v2 v2.5.0 h1:zx5lfQbNX3za4VegID97IeY+M+BmfgHxWJTYA94sxok=
 github.com/Luzifer/rconfig/v2 v2.5.0/go.mod h1:eGWUPQeCPv/Pr/p0hjmwFgI20uqvwi/Szen69hUzGzU=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
@@ -12,8 +14,8 @@ github.com/gregdel/pushover v1.3.0 h1:CewbxqsThoN/1imgwkDKFkRkltaQMoyBV0K9IquQLt
 github.com/gregdel/pushover v1.3.0/go.mod h1:EcaO66Nn1StkpEm1iKtBTV3d2A16SoMsVER1PthX7to=
 github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI=
 github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
-github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
+github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
-github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
@@ -30,13 +32,16 @@ github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcU
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/teambition/rrule-go v1.7.2/go.mod h1:mBJ1Ht5uboJ6jexKdNUJg2NcwP8uUMNvStWXlJD3MvU=
 github.com/teambition/rrule-go v1.8.2/go.mod h1:Ieq5AbrKGciP1V//Wq8ktsTXwSwJHDD5mD/wLBGl3p4=
-golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8 h1:0A+M6Uqn+Eje4kHMK80dtF3JCXC4ykBgQG4Fe06QRhQ=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.18.0 h1:DBdB3niSjOA/O0blCZBqDefyWNYveAYMNF1Wum0DYQ4=
+golang.org/x/sys v0.18.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/validator.v2 v2.0.1 h1:xF0KWyGWXm/LM2G1TrEjqOu4pa6coO9AlWSf3msVfDY=
 gopkg.in/validator.v2 v2.0.1/go.mod h1:lIUZBlB3Im4s/eYp39Ry/wkR02yOPhZ9IwIRBjuPuG8=
+gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
+gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

main.go

@@ -6,27 +6,24 @@ import (
 	"sync"
 	"time"
 
+	"git.luzifer.io/luzifer/birthday-notifier/pkg/config"
 	"git.luzifer.io/luzifer/birthday-notifier/pkg/dateutil"
+	"git.luzifer.io/luzifer/birthday-notifier/pkg/formatter"
 	"git.luzifer.io/luzifer/birthday-notifier/pkg/notifier"
 	"github.com/emersion/go-vcard"
 	"github.com/pkg/errors"
 	"github.com/robfig/cron/v3"
 	"github.com/sirupsen/logrus"
 
+	"github.com/Luzifer/go_helpers/v2/fieldcollection"
 	"github.com/Luzifer/rconfig/v2"
 )
 
 var (
 	cfg = struct {
-		FetchInterval       time.Duration `flag:"fetch-interval" default:"1h" description:"How often to fetch birthdays from CardDAV"`
+		Config         string `flag:"config,c" default:"config.yaml" description:"Configuration file path"`
-		LogLevel            string        `flag:"log-level" default:"info" description:"Log level (debug, info, warn, error, fatal)"`
+		LogLevel       string `flag:"log-level" default:"info" description:"Log level (debug, info, warn, error, fatal)"`
-		NotifyDaysInAdvance []int         `flag:"notify-days-in-advance" default:"1" description:"Send notification X days before birthday"`
+		VersionAndExit bool   `flag:"version" default:"false" description:"Prints current version and exits"`
-		NotifyVia           []string      `flag:"notify-via" default:"log" description:"How to send the notification (log, pushover, slack)"`
-		WebdavBaseURL       string        `flag:"webdav-base-url" default:"" description:"Webdav server to connect to"`
-		WebdavPass          string        `flag:"webdav-pass" default:"" description:"Password for the Webdav user"`
-		WebdavPrincipal     string        `flag:"webdav-principal" default:"principals/users/%s" description:"Principal format to fetch the addressbooks for (%s will be replaced with the webdav-user)"`
-		WebdavUser          string        `flag:"webdav-user" default:"" description:"Username for Webdav login"`
-		VersionAndExit      bool          `flag:"version" default:"false" description:"Prints current version and exits"`
 	}{}
 
 	birthdays     []birthdayEntry
@@ -61,33 +58,40 @@ func main() {
 		os.Exit(0)
 	}
 
-	var notifiers []notifier.Notifier
+	configFile, err := config.LoadFromFile(cfg.Config)
-	for _, nv := range cfg.NotifyVia {
+	if err != nil {
-		notify := getNotifierByName(nv)
+		logrus.WithError(err).Fatal("loading configuration file")
-		if notify == nil {
-			logrus.Fatal("unknown notifier specified")
-		}
-		notifiers = append(notifiers, notify)
 	}
 
-	if birthdays, err = fetchBirthdays(); err != nil {
+	if err = validateNotifierConfigs(configFile); err != nil {
+		logrus.WithError(err).Fatal("validating configuration")
+	}
+
+	if err = formatter.SetTemplate(configFile.Template); err != nil {
+		logrus.WithError(err).Fatal("setting template")
+	}
+
+	if birthdays, err = fetchBirthdays(configFile.Webdav); err != nil {
 		logrus.WithError(err).Fatal("initially fetching birthdays")
 	}
 
 	crontab := cron.New()
 
 	// Periodically update birthdays
-	if _, err = crontab.AddFunc(fmt.Sprintf("@every %s", cfg.FetchInterval), cronFetchBirthdays); err != nil {
+	if _, err = crontab.AddFunc(
+		fmt.Sprintf("@every %s", configFile.Webdav.FetchInterval),
+		cronFetchBirthdays(configFile.Webdav),
+	); err != nil {
 		logrus.WithError(err).Fatal("adding update-cron")
 	}
 
 	// Send notifications at midnight
-	if _, err = crontab.AddFunc("@midnight", cronSendNotifications(notifiers)); err != nil {
+	if _, err = crontab.AddFunc("@midnight", cronSendNotifications(configFile)); err != nil {
 		logrus.WithError(err).Fatal("adding update-cron")
 	}
 
 	logrus.WithFields(logrus.Fields{
-		"advance": cfg.NotifyDaysInAdvance,
+		"advance": configFile.NotifyDaysInAdvance,
 		"version": version,
 	}).Info("birthday-notifier started")
 	crontab.Start()
@@ -97,36 +101,45 @@ func main() {
 	}
 }
 
-func cronFetchBirthdays() {
+func cronFetchBirthdays(webdavConfig config.WebdavConfig) func() {
-	birthdaysLock.Lock()
+	return func() {
-	defer birthdaysLock.Unlock()
+		birthdaysLock.Lock()
+		defer birthdaysLock.Unlock()
 
-	var err error
+		var err error
-	if birthdays, err = fetchBirthdays(); err != nil {
+		if birthdays, err = fetchBirthdays(webdavConfig); err != nil {
-		logrus.WithError(err).Error("updating birthdays")
+			logrus.WithError(err).Error("updating birthdays")
+		}
 	}
 }
 
-func cronSendNotifications(notifiers []notifier.Notifier) func() {
+func cronSendNotifications(configFile config.File) func() {
 	return func() {
 		birthdaysLock.Lock()
 		defer birthdaysLock.Unlock()
 
 		for _, b := range birthdays {
-			for _, advanceDays := range append(cfg.NotifyDaysInAdvance, 0) {
+			for _, advanceDays := range append(configFile.NotifyDaysInAdvance, 0) {
 				if !dateutil.IsToday(notifyDate(dateutil.ProjectToNextBirthday(b.birthday), advanceDays)) {
 					continue
 				}
 
-				for i := range notifiers {
+				for i := range configFile.Notifiers {
-					go func(n notifier.Notifier, contact vcard.Card, when time.Time) {
+					notifyInstance := getNotifierByName(configFile.Notifiers[i].Type)
-						if err := n.SendNotification(contact, when); err != nil {
+
+					go func(
+						n notifier.Notifier,
+						settings *fieldcollection.FieldCollection,
+						contact vcard.Card,
+						when time.Time,
+					) {
+						if err := n.SendNotification(settings, contact, when); err != nil {
 							logrus.
 								WithError(err).
 								WithField("name", contact.Get(vcard.FieldFormattedName).Value).
 								Error("sending notification")
 						}
-					}(notifiers[i], b.contact, b.birthday)
+					}(notifyInstance, configFile.Notifiers[i].Settings, b.contact, b.birthday)
 				}
 			}
 		}
@@ -136,3 +149,20 @@ func cronSendNotifications(notifiers []notifier.Notifier) func() {
 func notifyDate(t time.Time, daysInAdvance int) time.Time {
 	return time.Date(t.Year(), t.Month(), t.Day()-daysInAdvance, 0, 0, 0, 0, time.Local)
 }
+
+func validateNotifierConfigs(configFile config.File) (err error) {
+	for i := range configFile.Notifiers {
+		notifierCfg := configFile.Notifiers[i]
+
+		n := getNotifierByName(notifierCfg.Type)
+		if n == nil {
+			return fmt.Errorf("notifier %q does not exist", notifierCfg.Type)
+		}
+
+		if err = n.ValidateSettings(notifierCfg.Settings); err != nil {
+			return fmt.Errorf("settings for %q are invalid: %w", notifierCfg.Type, err)
+		}
+	}
+
+	return nil
+}

pkg/config/config.go

@@ -0,0 +1,90 @@
+// Package config contains parser and structure for the configuration
+// of the tool
+package config
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"time"
+
+	"git.luzifer.io/luzifer/birthday-notifier/pkg/formatter"
+	"github.com/Luzifer/go_helpers/v2/fieldcollection"
+	"github.com/sirupsen/logrus"
+	"gopkg.in/yaml.v3"
+)
+
+// WebdavPrincipalNextcloud is the principal default used for config
+// files on parse and represents the principal format used by Nextcloud
+const WebdavPrincipalNextcloud = "principals/users/%s"
+
+type (
+	// File contains the structure of the YAML configuration file
+	File struct {
+		NotifyDaysInAdvance []int            `yaml:"notifyDaysInAdvance"`
+		Notifiers           []NotifierConfig `yaml:"notifiers"`
+
+		Template string `yaml:"template"`
+
+		Webdav WebdavConfig `yaml:"webdav"`
+	}
+
+	// NotifierConfig contains the type of the notifier and the settings
+	// for it required to execute
+	NotifierConfig struct {
+		Type     string                           `yaml:"type"`
+		Settings *fieldcollection.FieldCollection `yaml:"settings"`
+	}
+
+	// WebdavConfig defines how to interact with the Webdav server
+	WebdavConfig struct {
+		BaseURL       string        `yaml:"baseURL"`
+		FetchInterval time.Duration `yaml:"fetchInterval"`
+		Pass          string        `yaml:"pass"`
+		Principal     string        `yaml:"principal"`
+		User          string        `yaml:"user"`
+	}
+)
+
+// Load parses the given reader over a default configuration replacing
+// the fields specified in the reader
+func Load(r io.Reader) (f File, err error) {
+	f = defaultConfig()
+	dec := yaml.NewDecoder(r)
+
+	dec.KnownFields(true)
+	if err = dec.Decode(&f); err != nil {
+		return f, fmt.Errorf("decoding yaml: %w", err)
+	}
+
+	return f, nil
+}
+
+// LoadFromFile is a convenience wrapper around Load to read the config
+// from file system
+func LoadFromFile(filePath string) (f File, err error) {
+	inFile, err := os.Open(filePath) //#nosec G304 -- Intended to load a given path
+	if err != nil {
+		return f, fmt.Errorf("opening file: %w", err)
+	}
+	defer func() {
+		if err := inFile.Close(); err != nil {
+			logrus.WithError(err).Error("closing config file (leaked fd)")
+		}
+	}()
+
+	return Load(inFile)
+}
+
+func defaultConfig() File {
+	return File{
+		NotifyDaysInAdvance: nil,
+
+		Template: formatter.DefaultTemplate,
+
+		Webdav: WebdavConfig{
+			FetchInterval: time.Hour,
+			Principal:     WebdavPrincipalNextcloud,
+		},
+	}
+}

pkg/formatter/formatter.go

@@ -5,7 +5,6 @@ package formatter
 import (
 	"bytes"
 	"fmt"
-	"os"
 	"regexp"
 	"strings"
 	"text/template"
@@ -18,7 +17,9 @@ import (
 const timeDay = 24 * time.Hour
 
 var (
-	defaultTemplate = regexp.MustCompile(`\s+`).ReplaceAllString(strings.TrimSpace(strings.ReplaceAll(`
+	// DefaultTemplate contains the template used in testing and as a
+	// default in the config package
+	DefaultTemplate = regexp.MustCompile(`\s+`).ReplaceAllString(strings.TrimSpace(strings.ReplaceAll(`
 {{ .contact | getName }} has their birthday {{ if .when | isToday -}} today {{- else -}} on {{ (.when | projectToNext).Format "Mon, 02 Jan" }} {{- end }}.
 {{ if gt .when.Year 1 -}}They are turning {{ .when | getAge }}.{{- end }}
 `, "\n", " ")), " ")
@@ -26,24 +27,6 @@ var (
 	notifyTpl *template.Template
 )
 
-func init() {
-	rawTpl := defaultTemplate
-	if tpl := os.Getenv("NOTIFICATION_TEMPLATE"); tpl != "" {
-		rawTpl = tpl
-	}
-
-	var err error
-	notifyTpl, err = template.New("notification").Funcs(template.FuncMap{
-		"getAge":        getAge,
-		"getName":       getContactName,
-		"isToday":       dateutil.IsToday,
-		"projectToNext": dateutil.ProjectToNextBirthday,
-	}).Parse(rawTpl)
-	if err != nil {
-		panic(fmt.Errorf("parsing notification template: %w", err))
-	}
-}
-
 // FormatNotificationText takes the notification template and renders
 // the contact / birthday date into a text to submit in the notification
 func FormatNotificationText(contact vcard.Card, when time.Time) (text string, err error) {
@@ -75,6 +58,24 @@ func FormatNotificationTitle(contact vcard.Card) (title string) {
 	return title
 }
 
+// SetTemplate initializes the template to use in the
+// FormatNotificationText function. This MUST be called before first
+// use of the FormatNotificationText function.
+func SetTemplate(rawTpl string) error {
+	var err error
+	notifyTpl, err = template.New("notification").Funcs(template.FuncMap{
+		"getAge":        getAge,
+		"getName":       getContactName,
+		"isToday":       dateutil.IsToday,
+		"projectToNext": dateutil.ProjectToNextBirthday,
+	}).Parse(rawTpl)
+	if err != nil {
+		return fmt.Errorf("parsing notification template: %w", err)
+	}
+
+	return nil
+}
+
 func getAge(t time.Time) int {
 	return dateutil.ProjectToNextBirthday(t).Year() - t.Year()
 }

pkg/formatter/formatter_test.go

@@ -20,6 +20,8 @@ func getTestVCard(t *testing.T, content string) vcard.Card {
 }
 
 func TestFormatNotificationText(t *testing.T) {
+	require.NoError(t, SetTemplate(DefaultTemplate))
+
 	card := getTestVCard(t, `BEGIN:VCARD
 VERSION:4.0
 N:Bloggs;Joe;;;

pkg/notifier/log/log.go

@@ -7,6 +7,7 @@ import (
 
 	"git.luzifer.io/luzifer/birthday-notifier/pkg/formatter"
 	"git.luzifer.io/luzifer/birthday-notifier/pkg/notifier"
+	"github.com/Luzifer/go_helpers/v2/fieldcollection"
 	"github.com/emersion/go-vcard"
 	"github.com/sirupsen/logrus"
 )
@@ -19,7 +20,7 @@ type (
 var _ notifier.Notifier = Notifier{}
 
 // SendNotification implements the Notifier interface
-func (Notifier) SendNotification(contact vcard.Card, when time.Time) error {
+func (Notifier) SendNotification(_ *fieldcollection.FieldCollection, contact vcard.Card, when time.Time) error {
 	if contact.Name() == nil {
 		return fmt.Errorf("contact has no name")
 	}
@@ -32,3 +33,9 @@ func (Notifier) SendNotification(contact vcard.Card, when time.Time) error {
 	logrus.WithField("name", contact.Name().GivenName).Info(text)
 	return nil
 }
+
+// ValidateSettings implements the Notifier interface
+func (Notifier) ValidateSettings(*fieldcollection.FieldCollection) error {
+	// We don't take settings so everything is fine
+	return nil
+}

pkg/notifier/notifier.go

@@ -4,6 +4,7 @@ package notifier
 import (
 	"time"
 
+	"github.com/Luzifer/go_helpers/v2/fieldcollection"
 	"github.com/emersion/go-vcard"
 )
 
@@ -13,7 +14,13 @@ type (
 		// SendNotification will be called with the contact and the
 		// time when the birthday actually is. The method is therefore
 		// also called when a notification in advance is configured and
-		// needs to properly format the notification for that.
+		// needs to properly format the notification for that. The settings
-		SendNotification(contact vcard.Card, when time.Time) error
+		// passed through this call MUST NOT be stored.
+		SendNotification(settings *fieldcollection.FieldCollection, contact vcard.Card, when time.Time) error
+
+		// ValidateSettings is called after configuration load to validate
+		// the settings are suitable for the notifier and do not yield
+		// surprising errors when doing the real notifications
+		ValidateSettings(settings *fieldcollection.FieldCollection) error
 	}
 )

pkg/notifier/pushover/pushover.go

@@ -4,11 +4,11 @@ package pushover
 
 import (
 	"fmt"
-	"os"
 	"time"
 
 	"git.luzifer.io/luzifer/birthday-notifier/pkg/formatter"
 	"git.luzifer.io/luzifer/birthday-notifier/pkg/notifier"
+	"github.com/Luzifer/go_helpers/v2/fieldcollection"
 	"github.com/emersion/go-vcard"
 	"github.com/gregdel/pushover"
 )
@@ -18,26 +18,18 @@ type (
 	Notifier struct{}
 )
 
-var _ notifier.Notifier = Notifier{}
+var (
+	ptrStrEmpty = func(v string) *string { return &v }("")
+
+	_ notifier.Notifier = Notifier{}
+)
 
 // SendNotification implements the Notifier interface
-func (Notifier) SendNotification(contact vcard.Card, when time.Time) error {
+func (Notifier) SendNotification(settings *fieldcollection.FieldCollection, contact vcard.Card, when time.Time) error {
 	if contact.Name() == nil {
 		return fmt.Errorf("contact has no name")
 	}
 
-	var (
-		apiToken = os.Getenv("PUSHOVER_API_TOKEN")
-		userKey  = os.Getenv("PUSHOVER_USER_KEY")
-	)
-
-	if apiToken == "" {
-		return fmt.Errorf("missing PUSHOVER_API_TOKEN env variable")
-	}
-	if userKey == "" {
-		return fmt.Errorf("missing PUSHOVER_USER_KEY env variable")
-	}
-
 	text, err := formatter.FormatNotificationText(contact, when)
 	if err != nil {
 		return fmt.Errorf("rendering text: %w", err)
@@ -46,13 +38,26 @@ func (Notifier) SendNotification(contact vcard.Card, when time.Time) error {
 	message := &pushover.Message{
 		Message: text,
 		Title:   formatter.FormatNotificationTitle(contact),
-		Sound:   os.Getenv("PUSHOVER_SOUND"),
+		Sound:   settings.MustString("sound", ptrStrEmpty),
 	}
 
-	if _, err = pushover.New(apiToken).
+	if _, err = pushover.New(settings.MustString("apiToken", nil)).
-		SendMessage(message, pushover.NewRecipient(userKey)); err != nil {
+		SendMessage(message, pushover.NewRecipient(settings.MustString("userKey", nil))); err != nil {
 		return fmt.Errorf("sending notification: %w", err)
 	}
 
 	return nil
 }
+
+// ValidateSettings implements the Notifier interface
+func (Notifier) ValidateSettings(settings *fieldcollection.FieldCollection) (err error) {
+	if v, err := settings.String("apiToken"); err != nil || v == "" {
+		return fmt.Errorf("apiToken is expected to be non-empty string")
+	}
+
+	if v, err := settings.String("userKey"); err != nil || v == "" {
+		return fmt.Errorf("userKey is expected to be non-empty string")
+	}
+
+	return nil
+}

pkg/notifier/slack/slack.go

@@ -8,11 +8,11 @@ import (
 	"encoding/json"
 	"fmt"
 	"net/http"
-	"os"
 	"time"
 
 	"git.luzifer.io/luzifer/birthday-notifier/pkg/formatter"
 	"git.luzifer.io/luzifer/birthday-notifier/pkg/notifier"
+	"github.com/Luzifer/go_helpers/v2/fieldcollection"
 	"github.com/emersion/go-vcard"
 	"github.com/sirupsen/logrus"
 )
@@ -24,20 +24,18 @@ type (
 	Notifier struct{}
 )
 
-var _ notifier.Notifier = Notifier{}
+var (
+	ptrStrEmpty = func(v string) *string { return &v }("")
+
+	_ notifier.Notifier = Notifier{}
+)
 
 // SendNotification implements the Notifier interface
-func (Notifier) SendNotification(contact vcard.Card, when time.Time) error {
+func (Notifier) SendNotification(settings *fieldcollection.FieldCollection, contact vcard.Card, when time.Time) error {
 	if contact.Name() == nil {
 		return fmt.Errorf("contact has no name")
 	}
 
-	webhookURL := os.Getenv("SLACK_WEBHOOK")
-
-	if webhookURL == "" {
-		return fmt.Errorf("missing SLACK_WEBHOOK env variable")
-	}
-
 	text, err := formatter.FormatNotificationText(contact, when)
 	if err != nil {
 		return fmt.Errorf("rendering text: %w", err)
@@ -50,10 +48,10 @@ func (Notifier) SendNotification(contact vcard.Card, when time.Time) error {
 		Text      string `json:"text"`
 		Username  string `json:"username,omitempty"`
 	}{
-		Channel:   os.Getenv("SLACK_CHANNEL"),
+		Channel:   settings.MustString("channel", ptrStrEmpty),
-		IconEmoji: os.Getenv("SLACK_ICON_EMOJI"),
+		IconEmoji: settings.MustString("iconEmoji", ptrStrEmpty),
 		Text:      text,
-		Username:  os.Getenv("SLACK_USERNAME"),
+		Username:  settings.MustString("username", ptrStrEmpty),
 	}); err != nil {
 		return fmt.Errorf("encoding hook payload: %w", err)
 	}
@@ -61,7 +59,7 @@ func (Notifier) SendNotification(contact vcard.Card, when time.Time) error {
 	ctx, cancel := context.WithTimeout(context.Background(), webhookPostTimeout)
 	defer cancel()
 
-	req, err := http.NewRequestWithContext(ctx, http.MethodPost, webhookURL, payload)
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, settings.MustString("webhook", nil), payload)
 	if err != nil {
 		return fmt.Errorf("creating request: %w", err)
 	}
@@ -83,3 +81,12 @@ func (Notifier) SendNotification(contact vcard.Card, when time.Time) error {
 
 	return nil
 }
+
+// ValidateSettings implements the Notifier interface
+func (Notifier) ValidateSettings(settings *fieldcollection.FieldCollection) (err error) {
+	if v, err := settings.String("webhook"); err != nil || v == "" {
+		return fmt.Errorf("webhook is expected to be non-empty string")
+	}
+
+	return nil
+}