chore: initial commit

.gitignore

@@ -0,0 +1,2 @@
+main
+

LICENSE

@@ -0,0 +1,25 @@
+This is free and unencumbered software released into the public domain.
+
+Anyone is free to copy, modify, publish, use, compile, sell, or
+distribute this software, either in source code form or as a compiled
+binary, for any purpose, commercial or non-commercial, and by any
+means.
+
+In jurisdictions that recognize copyright laws, the author or authors
+of this software dedicate any and all copyright interest in the
+software to the public domain. We make this dedication for the benefit
+of the public at large and to the detriment of our heirs and
+successors. We intend this dedication to be an overt act of
+relinquishment in perpetuity of all present and future rights to this
+software under copyright law.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
+For more information, please refer to <https://unlicense.org>
+

cmd/main.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"context"
+	"log"
+
+	"github.com/aws/aws-sdk-go/aws/session"
+	"github.com/aws/aws-sdk-go/service/sqs"
+	"github.com/coreos/go-systemd/dbus"
+	"github.com/vranystepan/unit-reloader/internal/reloader"
+	"github.com/vranystepan/unit-reloader/pkg/config"
+)
+
+func main() {
+	cfg, err := config.New()
+	if err != nil {
+		log.Fatalf("could not load configuration: %s", err)
+	}
+
+	// initialize dbus client
+	dbusClient, err := dbus.New()
+	if err != nil {
+		log.Fatalf("could not initialize dbus client: %s", err)
+	}
+
+	// initialize SQS client
+	sess := session.Must(session.NewSessionWithOptions(session.Options{
+		SharedConfigState: session.SharedConfigEnable,
+	}))
+	sqsClient := sqs.New(sess)
+
+	// start the main loop
+	ctx := context.Background()
+	reloader.Run(ctx, cfg, sqsClient, dbusClient)
+}

go.mod

@@ -0,0 +1,15 @@
+module github.com/vranystepan/unit-reloader
+
+go 1.19
+
+require (
+	github.com/aws/aws-sdk-go v1.44.162
+	github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf
+)
+
+require (
+	github.com/godbus/dbus/v5 v5.0.4 // indirect
+	github.com/jmespath/go-jmespath v0.4.0 // indirect
+)
+
+replace github.com/coreos/go-systemd => github.com/coreos/go-systemd/v22 v22.5.0

go.sum

@@ -0,0 +1,46 @@
+github.com/aws/aws-sdk-go v1.44.162 h1:hKAd+X+/BLxVMzH+4zKxbQcQQGrk2UhFX0OTu1Mhon8=
+github.com/aws/aws-sdk-go v1.44.162/go.mod h1:aVsgQcEevwlmQ7qHE9I3h+dtQgpqhFB+i8Phjh7fkwI=
+github.com/coreos/go-systemd/v22 v22.5.0 h1:RrqgGjYQKalulkV8NGVIfkXQf6YYmOyiJKk8iXXhfZs=
+github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/godbus/dbus/v5 v5.0.4 h1:9349emZab16e7zQvpmsbtjc18ykshndd8y2PG3sgJbA=
+github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
+github.com/jmespath/go-jmespath v0.4.0 h1:BEgLn5cpjn8UN1mAw4NjwDrS35OdebyEtFe+9YPoQUg=
+github.com/jmespath/go-jmespath v0.4.0/go.mod h1:T8mJZnbsbmF+m6zOOFylbeCJqk5+pHWvzYPziyZiYoo=
+github.com/jmespath/go-jmespath/internal/testify v1.5.1 h1:shLQSRRSCCPj3f2gpwzGwWFoC7ycTf1rcQZHOlsJ6N8=
+github.com/jmespath/go-jmespath/internal/testify v1.5.1/go.mod h1:L3OGu8Wl2/fWfCI6z80xFu9LTZmf1ZRjMHUOPmWr69U=
+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/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
+golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
+golang.org/x/net v0.1.0/go.mod h1:Cx3nUiGt4eDBEyega/BKRp+/AlGL8hYe7U9odMt2Cco=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
+golang.org/x/term v0.1.0/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
+golang.org/x/text v0.4.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.2.8 h1:obN1ZagJSUGI0Ek/LBmuj4SNLPfIny3KsKFopxRdj10=
+gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

internal/reloader/reloader.go

@@ -0,0 +1,48 @@
+package reloader
+
+import (
+	"context"
+	"log"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/service/sqs"
+	"github.com/coreos/go-systemd/dbus"
+	"github.com/vranystepan/unit-reloader/pkg/config"
+	dbusImpl "github.com/vranystepan/unit-reloader/pkg/dbus"
+	sqsImpl "github.com/vranystepan/unit-reloader/pkg/sqs"
+)
+
+func Run(ctx context.Context, cfg *config.Config, sqsClient *sqs.SQS, dbusClient *dbus.Conn) {
+
+	// consume messages in loop
+	for {
+
+		output, err := sqsClient.ReceiveMessage(&sqs.ReceiveMessageInput{
+			QueueUrl:            &cfg.QueueURL,
+			MaxNumberOfMessages: aws.Int64(int64(cfg.QueueMaxMessages)),
+			WaitTimeSeconds:     aws.Int64(int64(cfg.QueueWaitTime)),
+		})
+
+		if err != nil {
+			log.Printf("could not receive SQS messages: %s", err)
+		}
+
+		for _, message := range output.Messages {
+			log.Printf("processing SQS message %s: %s", *message.MessageId, *message.Body)
+			// TODO: filter messages
+
+			// perform systemd action
+			err = dbusImpl.Do(ctx, dbusClient, cfg.UnitName, cfg.UnitAction)
+			if err != nil {
+				log.Printf("could not perform dbus action: %s", err)
+			}
+
+			// delete message
+			err = sqsImpl.Delete(sqsClient, cfg.QueueURL, message)
+			if err != nil {
+				log.Printf("could not delete message: %s", err)
+			}
+		}
+
+	}
+}

pkg/config/config.go

@@ -0,0 +1,50 @@
+package config
+
+import (
+	"flag"
+	"fmt"
+
+	"github.com/vranystepan/unit-reloader/pkg/util"
+)
+
+type Config struct {
+	QueueURL         string
+	UnitName         string
+	UnitAction       string
+	QueueMaxMessages int
+	QueueWaitTime    int
+}
+
+func New() (*Config, error) {
+	queueURL := flag.String("queue-url", "", "SQS queue URL")
+	unit := flag.String("unit", "", "systemd unit name")
+	action := flag.String("action", "", "systemd unit action")
+
+	flag.Parse()
+
+	// perform basic sanity checks
+	if *queueURL == "" {
+		return nil, fmt.Errorf("queue-url can't be emtpy")
+	}
+
+	if *unit == "" {
+		return nil, fmt.Errorf("unit can't be emtpy")
+	}
+
+	if *action == "" {
+		return nil, fmt.Errorf("action can't be emtpy")
+	}
+
+	if !util.StringInSlice(*action, []string{"start", "stop", "restart"}) {
+		return nil, fmt.Errorf("action can be only start, stop or restart")
+	}
+
+	// get the config
+	return &Config{
+		QueueURL:         *queueURL,
+		UnitName:         *unit,
+		UnitAction:       *action,
+		QueueMaxMessages: 1,
+		QueueWaitTime:    20,
+	}, nil
+}

pkg/dbus/dbus.go

@@ -0,0 +1,36 @@
+package dbus
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/coreos/go-systemd/dbus"
+)
+
+func Do(ctx context.Context, dbusClient *dbus.Conn, unit string, action string) error {
+	switch action {
+	case "start":
+		return Start(ctx, dbusClient, unit)
+	case "stop":
+		return Stop(ctx, dbusClient, unit)
+	case "restart":
+		return Restart(ctx, dbusClient, unit)
+	default:
+		return fmt.Errorf("action %s is not defined", action)
+	}
+}
+
+func Restart(ctx context.Context, dbusClient *dbus.Conn, unit string) error {
+	_, err := dbusClient.RestartUnitContext(ctx, unit, "replace", nil)
+	return err
+}
+
+func Start(ctx context.Context, dbusClient *dbus.Conn, unit string) error {
+	_, err := dbusClient.StartUnitContext(ctx, unit, "replace", nil)
+	return err
+}
+
+func Stop(ctx context.Context, dbusClient *dbus.Conn, unit string) error {
+	_, err := dbusClient.StopUnitContext(ctx, unit, "replace", nil)
+	return err
+}

pkg/sqs/ack.go

@@ -0,0 +1,15 @@
+package sqs
+
+import (
+	"github.com/aws/aws-sdk-go/service/sqs"
+)
+
+func Delete(sqsClient *sqs.SQS, queue string, message *sqs.Message) error {
+	request := &sqs.DeleteMessageInput{
+		QueueUrl:      &queue,
+		ReceiptHandle: message.ReceiptHandle,
+	}
+
+	_, err := sqsClient.DeleteMessage(request)
+	return err
+}

pkg/util/slice.go

@@ -0,0 +1,10 @@
+package util
+
+func StringInSlice(a string, list []string) bool {
+	for _, b := range list {
+		if b == a {
+			return true
+		}
+	}
+	return false
+}