Initial version

2024-03-11 13:16:48 +01:00 · 2024-03-11 13:16:48 +01:00 · db4c17256c
commit db4c17256c
18 changed files with 989 additions and 0 deletions
--- a/.gitignore
+++ b/.gitignore
@ -0,0 +1 @@
+birthday-notifier
--- a/29
+++ b/29
@ -0,0 +1,29 @@
+FROM golang:alpine as builder
+
+COPY . /go/src/birthday-notifier
+WORKDIR /go/src/birthday-notifier
+
+RUN set -ex \
+ && apk add --update git \
+ && go install \
+      -ldflags "-X main.version=$(git describe --tags --always || echo dev)" \
+      -mod=readonly \
+      -modcacherw \
+      -trimpath
+
+
+FROM alpine:latest
+
+LABEL maintainer "Knut Ahlers <knut@ahlers.me>"
+
+RUN set -ex \
+ && apk --no-cache add \
+      ca-certificates \
+      tzdata
+
+COPY --from=builder /go/bin/birthday-notifier /usr/local/bin/birthday-notifier
+
+ENTRYPOINT ["/usr/local/bin/birthday-notifier"]
+CMD ["--"]
+
+# vim: set ft=Dockerfile:
--- a/202
+++ b/202
@ -0,0 +1,202 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
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+      any Contribution intentionally submitted for inclusion in the Work
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+      the terms of any separate license agreement you may have executed
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+   Copyright 2024- Knut Ahlers <knut@ahlers.me>
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
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+   See the License for the specific language governing permissions and
+   limitations under the License.
+
--- a/README.md
+++ b/README.md
@ -0,0 +1,41 @@
+# Luzifer / birthday-notifier
+
+Previously I used an app on my phone to notify me on upcoming birthdays: One day in advance and on the same day. Then that app decided to add a skew of one day and notify me too late…
+
+And that's why there is now a server based solution to notifying my of upcoming birthdays.
+
+Features:
+
+- Sync contacts using CardDAV
+- Extract birthdays from the contacts
+- Send notifications
+
+Hosted somewhere it's always running and configured properly and birthday notifications are coming in properly.
+
+## Usage
+
+```console
+# birthday-notifier --help
+Usage of birthday-notifier:
+      --fetch-interval duration       How often to fetch birthdays from CardDAV (default 1h0m0s)
+      --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])
+      --notify-via string             How to send the notification (one of: log, pushover) (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.
+
+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.
+
+### Notifier configuration
+
+- **`log`** - Just sends the notification to the console logs, no configuration available
+- **`pushover`** - Send notification via [Pushover](https://pushover.net)
+  - `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
+  - `PUSHOVER_SOUND` - (Optional) Specify a sound to use
--- a/caldav.go
+++ b/caldav.go
@ -0,0 +1,72 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"time"
+
+	"git.luzifer.io/luzifer/birthday-notifier/pkg/dateutil"
+	"github.com/emersion/go-vcard"
+	"github.com/emersion/go-webdav"
+	"github.com/emersion/go-webdav/carddav"
+	"github.com/sirupsen/logrus"
+)
+
+type (
+	birthdayEntry struct {
+		contact  vcard.Card
+		birthday time.Time
+	}
+)
+
+func fetchBirthdays() (birthdays []birthdayEntry, err error) {
+	client, err := carddav.NewClient(
+		webdav.HTTPClientWithBasicAuth(http.DefaultClient, cfg.WebdavUser, cfg.WebdavPass),
+		cfg.WebdavBaseURL,
+	)
+	if err != nil {
+		return nil, fmt.Errorf("creating carddav client: %w", err)
+	}
+
+	homeSet, err := client.FindAddressBookHomeSet(
+		context.Background(),
+		fmt.Sprintf(cfg.WebdavPrincipal, cfg.WebdavUser),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("getting addressbook-home-set: %w", err)
+	}
+
+	books, err := client.FindAddressBooks(context.Background(), homeSet)
+	if err != nil {
+		return nil, fmt.Errorf("getting addressbooks: %w", err)
+	}
+
+	for _, book := range books {
+		contacts, err := client.QueryAddressBook(context.Background(), book.Path, &carddav.AddressBookQuery{})
+		if err != nil {
+			return nil, fmt.Errorf("getting contacts: %w", err)
+		}
+
+		for _, address := range contacts {
+			bday := address.Card.Get(vcard.FieldBirthday)
+			if bday == nil {
+				continue
+			}
+
+			bdayDate, err := dateutil.Parse(bday)
+			if err != nil {
+				logrus.WithField("date", bday).WithError(err).Error("parsing birthday")
+				continue
+			}
+
+			birthdays = append(birthdays, birthdayEntry{
+				contact:  address.Card,
+				birthday: bdayDate,
+			})
+		}
+	}
+
+	logrus.Infof("fetched %d birthdays from contacts", len(birthdays))
+	return birthdays, nil
+}
--- a/go.mod
+++ b/go.mod
@ -0,0 +1,23 @@
+module git.luzifer.io/luzifer/birthday-notifier
+
+go 1.22.0
+
+require (
+	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
+	github.com/gregdel/pushover v1.3.0
+	github.com/pkg/errors v0.9.1
+	github.com/robfig/cron/v3 v3.0.1
+	github.com/sirupsen/logrus v1.9.3
+	github.com/stretchr/testify v1.8.4
+)
+
+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
+	gopkg.in/validator.v2 v2.0.1 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
--- a/go.sum
+++ b/go.sum
@ -0,0 +1,42 @@
+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=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/emersion/go-ical v0.0.0-20220601085725-0864dccc089f/go.mod h1:2MKFUgfNMULRxqZkadG1Vh44we3y5gJAtTBlVsx1BKQ=
+github.com/emersion/go-vcard v0.0.0-20230815062825-8fda7d206ec9 h1:ATgqloALX6cHCranzkLb8/zjivwQ9DWWDCQRnxTPfaA=
+github.com/emersion/go-vcard v0.0.0-20230815062825-8fda7d206ec9/go.mod h1:HMJKR5wlh/ziNp+sHEDV2ltblO4JD2+IdDOWtGcQBTM=
+github.com/emersion/go-webdav v0.5.0 h1:Ak/BQLgAihJt/UxJbCsEXDPxS5Uw4nZzgIMOq3rkKjc=
+github.com/emersion/go-webdav v0.5.0/go.mod h1:ycyIzTelG5pHln4t+Y32/zBvmrM7+mV7x+V+Gx4ZQno=
+github.com/gregdel/pushover v1.3.0 h1:CewbxqsThoN/1imgwkDKFkRkltaQMoyBV0K9IquQLtw=
+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 v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
+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=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/robfig/cron/v3 v3.0.1 h1:WdRxkvbJztn8LMz/QEvLN5sBU+xKpSqwwUO1Pjr4qDs=
+github.com/robfig/cron/v3 v3.0.1/go.mod h1:eQICP3HwyT7UooqI/z+Ov+PtYAWygg1TEWWzGIFLtro=
+github.com/sirupsen/logrus v1.9.3 h1:dueUQJ1C2q9oE3F7wvmSGAaVtTmUizReu6fjN8uqzbQ=
+github.com/sirupsen/logrus v1.9.3/go.mod h1:naHLuLoDiP4jHNo9R0sCBMtWGeIprob74mVsIT4qYEQ=
+github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
+github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+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=
+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.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=
--- a/main.go
+++ b/main.go
@ -0,0 +1,124 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"sync"
+	"time"
+
+	"git.luzifer.io/luzifer/birthday-notifier/pkg/dateutil"
+	"github.com/emersion/go-vcard"
+	"github.com/pkg/errors"
+	"github.com/robfig/cron/v3"
+	"github.com/sirupsen/logrus"
+
+	"github.com/Luzifer/rconfig/v2"
+)
+
+var (
+	cfg = struct {
+		FetchInterval       time.Duration `flag:"fetch-interval" default:"1h" description:"How often to fetch birthdays from CardDAV"`
+		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"`
+		NotifyVia           string        `flag:"notify-via" default:"log" description:"How to send the notification (one of: log, pushover)"`
+		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
+	birthdaysLock sync.Mutex
+
+	version = "dev"
+)
+
+func initApp() error {
+	rconfig.AutoEnv(true)
+	if err := rconfig.ParseAndValidate(&cfg); err != nil {
+		return errors.Wrap(err, "parsing cli options")
+	}
+
+	l, err := logrus.ParseLevel(cfg.LogLevel)
+	if err != nil {
+		return errors.Wrap(err, "parsing log-level")
+	}
+	logrus.SetLevel(l)
+
+	return nil
+}
+
+func main() {
+	var err error
+	if err = initApp(); err != nil {
+		logrus.WithError(err).Fatal("initializing app")
+	}
+
+	if cfg.VersionAndExit {
+		logrus.WithField("version", version).Info("birthday-notifier")
+		os.Exit(0)
+	}
+
+	notify := getNotifierByName(cfg.NotifyVia)
+	if notify == nil {
+		logrus.Fatal("unknown notifier specified")
+	}
+
+	if birthdays, err = fetchBirthdays(); 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), func() {
+		birthdaysLock.Lock()
+		defer birthdaysLock.Unlock()
+
+		if birthdays, err = fetchBirthdays(); err != nil {
+			logrus.WithError(err).Error("updating birthdays")
+		}
+	}); err != nil {
+		logrus.WithError(err).Fatal("adding update-cron")
+	}
+
+	// Send notifications at midnight
+	if _, err = crontab.AddFunc("@midnight", func() {
+		birthdaysLock.Lock()
+		defer birthdaysLock.Unlock()
+
+		for _, b := range birthdays {
+			for _, advanceDays := range append(cfg.NotifyDaysInAdvance, 0) {
+				if !dateutil.IsToday(notifyDate(dateutil.ProjectToNextBirthday(b.birthday), advanceDays)) {
+					continue
+				}
+
+				go func(contact vcard.Card, when time.Time) {
+					if err = notify.SendNotification(contact, when); err != nil {
+						logrus.
+							WithError(err).
+							WithField("name", contact.Get(vcard.FieldFormattedName).Value).
+							Error("sending notification")
+					}
+				}(b.contact, b.birthday)
+			}
+		}
+	}); err != nil {
+		logrus.WithError(err).Fatal("adding update-cron")
+	}
+
+	logrus.WithFields(logrus.Fields{
+		"advance": cfg.NotifyDaysInAdvance,
+		"version": version,
+	}).Info("birthday-notifier started")
+	crontab.Start()
+
+	for {
+		select {}
+	}
+}
+
+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)
+}
--- a/notifier.go
+++ b/notifier.go
@ -0,0 +1,20 @@
+package main
+
+import (
+	"git.luzifer.io/luzifer/birthday-notifier/pkg/notifier"
+	"git.luzifer.io/luzifer/birthday-notifier/pkg/notifier/log"
+	"git.luzifer.io/luzifer/birthday-notifier/pkg/notifier/pushover"
+)
+
+func getNotifierByName(name string) notifier.Notifier {
+	switch name {
+	case "log":
+		return log.Notifier{}
+
+	case "pushover":
+		return pushover.Notifier{}
+
+	default:
+		return nil
+	}
+}
--- a/pkg/dateutil/date.go
+++ b/pkg/dateutil/date.go
@ -0,0 +1,25 @@
+package dateutil
+
+import "time"
+
+// IsToday uses ProjectToNextBirthday to get the next birthday and
+// compares it to TodayStartOfDay
+func IsToday(t time.Time) bool {
+	return ProjectToNextBirthday(t).
+		Equal(TodayStartOfDay())
+}
+
+// ProjectToNextBirthday takes a birth date and projects it to the
+// next birthday being today or later
+func ProjectToNextBirthday(t time.Time) time.Time {
+	projected := time.Date(time.Now().Year(), t.Month(), t.Day(), 0, 0, 0, 0, time.Local)
+	if projected.Before(TodayStartOfDay()) {
+		projected = time.Date(time.Now().Year()+1, t.Month(), t.Day(), 0, 0, 0, 0, time.Local)
+	}
+	return projected
+}
+
+// TodayStartOfDay gets the start of the current day
+func TodayStartOfDay() time.Time {
+	return time.Date(time.Now().Year(), time.Now().Month(), time.Now().Day(), 0, 0, 0, 0, time.Local)
+}
--- a/pkg/dateutil/date_test.go
+++ b/pkg/dateutil/date_test.go
@ -0,0 +1,54 @@
+package dateutil
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+const timeDay = 24 * time.Hour
+
+func TestProjectToNextBirthday(t *testing.T) {
+	// Now should stay in the year
+	assert.Equal(
+		t,
+		time.Now().Year(),
+		ProjectToNextBirthday(time.Now()).Year(),
+	)
+
+	// Start-of-day should stay in the year
+	assert.Equal(
+		t,
+		time.Now().Year(),
+		ProjectToNextBirthday(TodayStartOfDay()).Year(),
+	)
+
+	// Tomorrow should stay in the year
+	assert.Equal(
+		t,
+		time.Now().Year(),
+		ProjectToNextBirthday(time.Now().Add(timeDay)).Year(),
+	)
+
+	// Yesterday should go to next year
+	assert.Equal(
+		t,
+		time.Now().Year()+1,
+		ProjectToNextBirthday(time.Now().Add(-timeDay)).Year(),
+	)
+
+	// Yesterday, thirty years ago should go to next year
+	assert.Equal(
+		t,
+		time.Now().Year()+1,
+		ProjectToNextBirthday(time.Date(time.Now().Year()-30, time.Now().Month(), time.Now().Day()-1, 0, 0, 0, 0, time.Local)).Year(),
+	)
+
+	// Tomorrow, thirty years ago should go to this year
+	assert.Equal(
+		t,
+		time.Now().Year(),
+		ProjectToNextBirthday(time.Date(time.Now().Year()-30, time.Now().Month(), time.Now().Day()+1, 0, 0, 0, 0, time.Local)).Year(),
+	)
+}
--- a/pkg/dateutil/parser.go
+++ b/pkg/dateutil/parser.go
@ -0,0 +1,57 @@
+// Package dateutil contains a helper to parse vcard dates
+package dateutil
+
+import (
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/emersion/go-vcard"
+)
+
+// Parse parses a vcard.Field into a time.Time
+func Parse(field *vcard.Field) (d time.Time, err error) {
+	if field == nil {
+		return d, fmt.Errorf("nil-field given")
+	}
+
+	rawDate := field.Value
+
+	if field.Params.Get("X-APPLE-OMIT-YEAR") != "" {
+		// Yay, Apple bullshit. They don't use the proper way defined in
+		// the RFC to omit the year but specify an invalid format with a
+		// replace. As the year 0001 is the "zero-time" in Go we replace
+		// the defined year (likely 1604) and move it to the year 1.
+		//
+		// Field should be something like this:
+		// &{1604-09-13 map[X-APPLE-OMIT-YEAR:[1604]] }
+
+		rawDate = strings.Replace(rawDate, field.Params.Get("X-APPLE-OMIT-YEAR"), "0001", 1)
+	}
+
+	// And now as we can't rely on `VALUE=DATE` being set (thanks Sabre)
+	// we're trying to walk possible formats until we found a matching
+	// one…
+
+	for _, fmtCandidate := range []string{
+		"20060102",        // Most likely, test first
+		"2006-01-02",      // Invalid as of RFC, used by Apple, see above
+		"060102",          // RFC compliant with 2-digit year
+		"--0102",          // RFC-compliant omit-year
+		"2006-01",         // Shouldn't exist as no day present but is valid
+		"2006",            // Somewhere in the year
+		"20060102T150405", // Full DATE-TIME in RFC
+		"20060102T1504",   // DATE-TIME in RFC without seconds
+		"20060102T15",     // DATE-TIME in RFC without minutes & seconds
+	} {
+		d, err = time.ParseInLocation(fmtCandidate, rawDate, time.Local)
+		if err == nil {
+			// Yay! It matched. Or at least it had the right length and numbers
+			// at the right places so it SHOULD have matched.
+			return d, nil
+		}
+	}
+
+	// Well. We found no matching format.
+	return d, fmt.Errorf("no format defined for %q", rawDate)
+}
--- a/pkg/dateutil/parser_test.go
+++ b/pkg/dateutil/parser_test.go
@ -0,0 +1,49 @@
+package dateutil
+
+import (
+	"testing"
+	"time"
+
+	"github.com/emersion/go-vcard"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestParseDate(t *testing.T) {
+	for _, tc := range []struct {
+		ExpectedTime time.Time
+		Field        *vcard.Field
+	}{
+		{
+			ExpectedTime: time.Date(2000, 2, 5, 0, 0, 0, 0, time.Local),
+			Field: &vcard.Field{
+				Value: "20000205",
+				Params: vcard.Params{
+					"VALUE": []string{"DATE"},
+				},
+			},
+		},
+		{
+			ExpectedTime: time.Date(1, 2, 15, 0, 0, 0, 0, time.Local),
+			Field: &vcard.Field{
+				Value: "1604-02-15",
+				Params: vcard.Params{
+					"X-APPLE-OMIT-YEAR": []string{"1604"},
+				},
+			},
+		},
+		{
+			ExpectedTime: time.Date(1, 11, 2, 0, 0, 0, 0, time.Local),
+			Field: &vcard.Field{
+				Value: "20221102",
+				Params: vcard.Params{
+					"X-APPLE-OMIT-YEAR": []string{"2022"},
+					"VALUE":             []string{"DATE"},
+				},
+			},
+		},
+	} {
+		d, err := Parse(tc.Field)
+		assert.NoError(t, err, tc.Field)
+		assert.Equal(t, tc.ExpectedTime, d)
+	}
+}
--- a/pkg/formatter/formatter.go
+++ b/pkg/formatter/formatter.go
@ -0,0 +1,72 @@
+// Package formatter contains a helper to format the date of a birthday
+// into a notification text
+package formatter
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"regexp"
+	"strings"
+	"text/template"
+	"time"
+
+	"git.luzifer.io/luzifer/birthday-notifier/pkg/dateutil"
+	"github.com/emersion/go-vcard"
+)
+
+const timeDay = 24 * time.Hour
+
+var (
+	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", " ")), " ")
+
+	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) {
+	buf := new(bytes.Buffer)
+
+	if err = notifyTpl.Execute(buf, map[string]any{
+		"contact": contact,
+		"when":    when,
+	}); err != nil {
+		return "", fmt.Errorf("executing template: %w", err)
+	}
+
+	return buf.String(), nil
+}
+
+func getAge(t time.Time) int {
+	return dateutil.ProjectToNextBirthday(t).Year() - t.Year()
+}
+
+func getContactName(contact vcard.Card) string {
+	if contact.Name() != nil && contact.Name().GivenName != "" {
+		return contact.Name().GivenName
+	}
+
+	return contact.FormattedNames()[0].Value
+}
--- a/pkg/formatter/formatter_test.go
+++ b/pkg/formatter/formatter_test.go
@ -0,0 +1,56 @@
+package formatter
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+	"time"
+
+	"git.luzifer.io/luzifer/birthday-notifier/pkg/dateutil"
+	"github.com/emersion/go-vcard"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func getTestVCard(t *testing.T, content string) vcard.Card {
+	c, err := vcard.NewDecoder(strings.NewReader(content)).Decode()
+	require.NoError(t, err)
+
+	return c
+}
+
+func TestFormatNotificationText(t *testing.T) {
+	card := getTestVCard(t, `BEGIN:VCARD
+VERSION:4.0
+N:Bloggs;Joe;;;
+FN:Joe Bloggs
+EMAIL;TYPE=home;PREF=1:me@joebloggs.com
+TEL;TYPE="cell,home";PREF=1:tel:+44 20 1234 5678
+ADR;TYPE=home;PREF=1:;;1 Trafalgar Square;London;;WC2N;United Kingdom
+URL;TYPE=home;PREF=1:http://joebloggs.com
+IMPP;TYPE=home;PREF=1:skype:joe.bloggs
+X-SOCIALPROFILE;TYPE=home;PREF=1:twitter:https://twitter.com/joebloggs
+END:VCARD`)
+
+	bday := time.Date(time.Now().Year()-30, time.Now().Month(), time.Now().Day(), 0, 0, 0, 0, time.Local)
+
+	txt, err := FormatNotificationText(card, bday)
+	require.NoError(t, err)
+	assert.Equal(t, "Joe has their birthday today. They are turning 30.", txt)
+
+	bday = bday.Add(timeDay)
+	txt, err = FormatNotificationText(card, bday)
+	require.NoError(t, err)
+	assert.Equal(t, fmt.Sprintf(
+		"Joe has their birthday on %s. They are turning 30.",
+		time.Now().Add(timeDay).Format("Mon, 02 Jan"),
+	), txt)
+
+	bday = bday.Add(-2 * timeDay)
+	txt, err = FormatNotificationText(card, bday)
+	require.NoError(t, err)
+	assert.Equal(t, fmt.Sprintf(
+		"Joe has their birthday on %s. They are turning 31.",
+		dateutil.ProjectToNextBirthday(time.Now().Add(-timeDay)).Format("Mon, 02 Jan"),
+	), txt)
+}
--- a/pkg/notifier/log/log.go
+++ b/pkg/notifier/log/log.go
@ -0,0 +1,34 @@
+// Package log contains a log-notifier for debugging
+package log
+
+import (
+	"fmt"
+	"time"
+
+	"git.luzifer.io/luzifer/birthday-notifier/pkg/formatter"
+	"git.luzifer.io/luzifer/birthday-notifier/pkg/notifier"
+	"github.com/emersion/go-vcard"
+	"github.com/sirupsen/logrus"
+)
+
+type (
+	// Notifier implements the notifier interface
+	Notifier struct{}
+)
+
+var _ notifier.Notifier = Notifier{}
+
+// SendNotification implements the Notifier interface
+func (Notifier) SendNotification(contact vcard.Card, when time.Time) error {
+	if contact.Name() == nil {
+		return fmt.Errorf("contact has no name")
+	}
+
+	text, err := formatter.FormatNotificationText(contact, when)
+	if err != nil {
+		return fmt.Errorf("rendering text: %w", err)
+	}
+
+	logrus.WithField("name", contact.Name().GivenName).Info(text)
+	return nil
+}
--- a/pkg/notifier/notifier.go
+++ b/pkg/notifier/notifier.go
@ -0,0 +1,19 @@
+// Package notifier includes the interface to implement in a notifier
+package notifier
+
+import (
+	"time"
+
+	"github.com/emersion/go-vcard"
+)
+
+type (
+	// Notifier specifies what a Notifier can do
+	Notifier interface {
+		// 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.
+		SendNotification(contact vcard.Card, when time.Time) error
+	}
+)
--- a/pkg/notifier/pushover/pushover.go
+++ b/pkg/notifier/pushover/pushover.go
@ -0,0 +1,69 @@
+// Package pushover provides a notifier to send birthday notifications
+// using Pushover.net
+package pushover
+
+import (
+	"fmt"
+	"os"
+	"time"
+
+	"git.luzifer.io/luzifer/birthday-notifier/pkg/formatter"
+	"git.luzifer.io/luzifer/birthday-notifier/pkg/notifier"
+	"github.com/emersion/go-vcard"
+	"github.com/gregdel/pushover"
+)
+
+type (
+	// Notifier implements the notifier interface
+	Notifier struct{}
+)
+
+var _ notifier.Notifier = Notifier{}
+
+// SendNotification implements the Notifier interface
+func (Notifier) SendNotification(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)
+	}
+
+	var title string
+	for _, fn := range contact.FormattedNames() {
+		if fn.Value != "" {
+			title = fmt.Sprintf("%s (Birthday)", fn.Value)
+		}
+	}
+
+	if title == "" {
+		title = fmt.Sprintf("%s %s (Birthday)", contact.Name().GivenName, contact.Name().FamilyName)
+	}
+
+	message := &pushover.Message{
+		Message: text,
+		Title:   title,
+		Sound:   os.Getenv("PUSHOVER_SOUND"),
+	}
+
+	if _, err = pushover.New(apiToken).
+		SendMessage(message, pushover.NewRecipient(userKey)); err != nil {
+		return fmt.Errorf("sending notification: %w", err)
+	}
+
+	return nil
+}