Refactored startup flags and Dockerfile accordingly (#56)

.run/Run SQS Client.run.xml

@@ -1,21 +1,12 @@
-<!--
-  ~ Copyright (c) 2022 AlertAvert.com.  All rights reserved.
-  ~
-  ~ Licensed under the Apache License, Version 2.0
-  ~ http://www.apache.org/licenses/LICENSE-2.0
-  ~
-  ~ Author: Marco Massenzio ([email protected])
-  -->
-
 <component name="ProjectRunConfigurationManager">
   <configuration default="false" name="Run SQS Client" type="GoApplicationRunConfiguration" factoryName="Go Application" editBeforeRun="true">
     <module name="statemachine" />
     <working_directory value="$PROJECT_DIR$" />
-    <parameters value="-endpoint http://localhost:4566 -q events -dest test.orders#25 -evt ship" />
+    <parameters value="-endpoint http://localhost:4566 -q events -dest test.orders#2 -evt accept" />
     <kind value="FILE" />
     <package value="github.com/massenz/go-statemachine/clients" />
     <directory value="$PROJECT_DIR$" />
     <filePath value="$PROJECT_DIR$/clients/sqs_client.go|$PROJECT_DIR$/clients/orders.go" />
     <method v="2" />
   </configuration>
-</component>
+</component>

cmd/main.go

@@ -7,10 +7,6 @@
  * Author: Marco Massenzio ([email protected])
  */
 
-// CLI to process Kubernetes Specs with a JSON configuration.
-//
-// Created by M. Massenzio, 2021-02-20
-
 package main
 
 import (
@@ -58,56 +54,54 @@ var (
 func main() {
 	defer close(eventsCh)
 
+	var acksTopic = flag.String("acks", "",
+		"(Requires `-notifications`) The name of the topic in SQS to publish Ok outcomes to; "+
+			"unless the -notify-errors-only flag is set")
+	var awsEndpoint = flag.String("endpoint-url", "",
+		"HTTP URL for AWS SQS to connect to; usually best left undefined, "+
+			"unless required for local testing purposes (LocalStack uses http://localhost:4566)")
+	var cluster = flag.Bool("cluster", false,
+		"If set, connects to Redis with cluster-mode enabled")
 	var debug = flag.Bool("debug", false,
 		"Verbose logs; better to avoid on Production services")
-	var trace = flag.Bool("trace", false,
-		"Enables trace logs for every API request and Pub/Sub event; it may impact performance, "+
-			"do not use in production or on heavily loaded systems ("+
-			"will override the -debug option)")
+	var eventsTopic = flag.String("events", "", "Topi name to receive events from")
+	var grpcPort = flag.Int("grpc-port", 7398, "The port for the gRPC server")
 	var localOnly = flag.Bool("local", false,
 		"If set, it only listens to incoming requests from the local host")
-	var port = flag.Int("http-port", 7399, "HTTP Server port for the REST API")
-	var redisUrl = flag.String("redis", "", "For single node redis instances: URI "+
-		"for the Redis instance (host:port). For redis clusters: a comma-separated list of redis nodes. "+
-		"If using an ElastiCache Redis cluster with cluster mode enabled, you can supply the configuration endpoint.")
-	var cluster = flag.Bool("cluster", false,
-		"If set, allows connecting to a Redis instance with cluster-mode enabled")
-	var awsEndpoint = flag.String("endpoint-url", "",
-		"HTTP URL for AWS SQS to connect to; usually best left undefined, "+
-			"unless required for local testing purposes (LocalStack uses http://localhost:4566)")
-	var eventsTopic = flag.String("events", "", "If defined, it will attempt to connect "+
-		"to the given SQS Queue to receive events from the Pub/Sub system")
+	var maxRetries = flag.Int("max-retries", storage.DefaultMaxRetries,
+		"Max number of attempts for a recoverable error to be retried against the Redis cluster")
 	var notificationsTopic = flag.String("notifications", "",
-		"The name of the notification topic in SQS to publish events' outcomes to; if not "+
+		"(optional) The name of the topic to publish events' outcomes to; if not "+
 			"specified, no outcomes will be published")
-	var acksTopic = flag.String("acks", "",
-		"(Requires `notifications`) The name of the acks topic in SQS to publish events' "+
-			"outcomes to; if specified, Ok outcomes will be published to the acks topic and other "+
-			"(error) outcomes to the notification topic")
 	var notifyErrorsOnly = flag.Bool("notify-errors-only", false,
-		"If set, only errors will be sent to notification topics")
-	var grpcPort = flag.Int("grpc-port", 7398, "The port for the gRPC server")
-	var maxRetries = flag.Int("max-retries", storage.DefaultMaxRetries,
-		"Max number of attempts for a recoverable error to be retried against the Redis cluster")
+		"If set, only errors will be sent to notification topic (cannot be used with -acks)")
+	var port = flag.Int("http-port", 7399, "HTTP Server port for the REST API")
+	var redisUrl = flag.String("redis", "", "For single node redis instances: URI "+
+		"for the Redis instance (host:port). For redis clusters: a comma-separated list of redis nodes. "+
+		"If using an ElastiCache Redis cluster with cluster mode enabled, "+
+		"this can also be the configuration endpoint.")
 	var timeout = flag.Duration("timeout", storage.DefaultTimeout,
 		"Timeout for Redis (as a Duration string, e.g. 1s, 20ms, etc.)")
+	var trace = flag.Bool("trace", false,
+		"Extremely verbose logs for every API request and Pub/Sub event; it may impact"+
+			" performance, do not use in production or on heavily loaded systems (will override the -debug option)")
 	flag.Parse()
 
-	logger.Info("Starting State Machine Server - Rel. %s", server.Release)
+	logger.Info("starting State Machine Server - Rel. %s", server.Release)
 
 	if *localOnly {
-		logger.Info("Listening on local interface only")
+		logger.Info("listening on local interface only")
 		host = "localhost"
 	} else {
-		logger.Warn("Listening on all interfaces")
+		logger.Warn("listening on all interfaces")
 	}
 	addr := fmt.Sprintf("%s:%d", host, *port)
 
 	if *redisUrl == "" {
 		logger.Warn("in-memory storage configured, all data will NOT survive a server restart")
 		store = storage.NewInMemoryStore()
 	} else {
-		logger.Info("Connecting to Redis server at %s", *redisUrl)
+		logger.Info("connecting to Redis server at %s", *redisUrl)
 		logger.Info("with timeout: %s, max-retries: %d", *timeout, *maxRetries)
 		store = storage.NewRedisStore(*redisUrl, *cluster, 1, *timeout, *maxRetries)
 	}
@@ -122,16 +116,19 @@ func main() {
 	if *acksTopic != "" && *notifyErrorsOnly {
 		logger.Fatal(fmt.Errorf("cannot set an acks topic while disabling errors notifications"))
 	}
-	logger.Info("Connecting to SQS Topic: %s", *eventsTopic)
+	logger.Info("connecting to SQS Topic: %s", *eventsTopic)
 	sub = pubsub.NewSqsSubscriber(eventsCh, awsEndpoint)
 	if sub == nil {
 		panic("Cannot create a valid SQS Subscriber")
 	}
 
 	if *notificationsTopic != "" {
-		logger.Info("Configuring Topic: %s", *notificationsTopic)
+		logger.Info("notifications topic: %s", *notificationsTopic)
+		if *notifyErrorsOnly {
+			logger.Info("only errors will be published to the notifications topic")
+		}
 		if *acksTopic != "" {
-			logger.Info("Configuring Topic: %s", *acksTopic)
+			logger.Info("acks topic: %s", *acksTopic)
 		}
 		notificationsCh = make(chan protos.EventResponse)
 		defer close(notificationsCh)
@@ -153,15 +150,15 @@ func main() {
 	// This should not be invoked until we have initialized all the services.
 	setLogLevel(*debug, *trace)
 
-	logger.Info("Starting Events Listener")
+	logger.Info("starting events listener")
 	go listener.ListenForMessages()
 
-	logger.Info("gRPC Server running at tcp://:%d", *grpcPort)
+	logger.Info("gRPC server running at tcp://:%d", *grpcPort)
 	go startGrpcServer(*grpcPort, eventsCh)
 
 	// TODO: configure & start server using TLS, if configured to do so.
 	scheme := "http"
-	logger.Info("HTTP Server (REST API) running at %s://%s", scheme, addr)
+	logger.Info("HTTP server (REST API) running at %s://%s", scheme, addr)
 	srv := server.NewHTTPServer(addr, serverLogLevel)
 	logger.Fatal(srv.ListenAndServe())
 }

docker/Dockerfile

@@ -12,11 +12,14 @@ RUN groupadd -r sm-bot && useradd -r -g sm-bot sm-bot
 # Fake AWS configuration to connect to LocalStack docker.
 ENV AWS_REGION=us-west-2 AWS_PROFILE=sm-bot
 
-# Sensible defaults for the server
-# See entrypoint.sh
-ENV SERVER_PORT=7399 DEBUG="" CLUSTER="" \
-    EVENTS_Q="events" ERRORS_Q="notifications" \
-    REDIS=redis REDIS_PORT=6379
+# Sensible defaults for the server, for reference
+# we list all the environment variables used by the
+# entrypoint script.
+#
+ENV GRPC_PORT=7398 SERVER_PORT=7399 DEBUG=""  \
+    EVENTS_Q="events" NOTIFICATIONS_Q="notifications" \
+    ACKS_Q="" ERRORS_ONLY=1 \
+    CLUSTER="" REDIS=redis REDIS_PORT=6379
 
 WORKDIR /app
 RUN chown sm-bot:sm-bot /app

docker/entrypoint.sh

@@ -10,17 +10,48 @@
 
 set -eu
 
-unset endpoint
+declare endpoint=""
+declare acks=""
+declare errors_only=""
+declare notifications=""
+declare retries=""
+declare timeout=""
+
 if [[ -n ${AWS_ENDPOINT:-} ]]
 then
-  endpoint="--endpoint-url ${AWS_ENDPOINT}"
+  endpoint="-endpoint-url ${AWS_ENDPOINT}"
+fi
+
+if [[ -n ${ERRORS_ONLY:-} ]]
+then
+  errors_only="-notify-errors-only"
 fi
 
+if [[ -n ${ACKS_Q:-} ]]
+then
+  acks="-acks ${ACKS_Q}"
+fi
+
+if [[ -n ${NOTIFICATIONS_Q:-} ]]
+then
+  notifications="-notifications ${NOTIFICATIONS_Q}"
+fi
+
+if [[ -n ${TIMEOUT:-} ]]
+then
+  timeout="-timeout ${TIMEOUT}"
+fi
+
+if [[ -n ${RETRIES:-} ]]
+then
+  retries="-max-retries ${RETRIES}"
+fi
 
-cmd="./sm-server -http-port ${SERVER_PORT} ${endpoint:-} \
-${CLUSTER:-} ${DEBUG:-} ${NOTIFY_ERRORS_ONLY:-} \
--redis ${REDIS}:${REDIS_PORT} -timeout ${TIMEOUT:-25ms} -max-retries ${RETRIES:-3} \
--events ${EVENTS_Q} -notifications ${ERRORS_Q} ${ACKS:-} \
+cmd="./sm-server -http-port ${SERVER_PORT} -grpc-port ${GRPC_PORT} \
+-events ${EVENTS_Q} -redis ${REDIS}:${REDIS_PORT} \
+${CLUSTER:-} ${DEBUG:-} ${endpoint} \
+${errors_only} ${timeout} ${retries} \
+${acks} ${notifications} \
 $@"
 
 echo $cmd