Added the jaeger-agent which will receive traces from instrumented services and send them to the collector.

Author: Uzziah Eyee

docker-compose.dev.yml

@@ -45,6 +45,21 @@ services:
       - "24224:24224/udp"
     env_file: log-shipper/.env
 
+  jaeger-agent:
+    build: jaeger-agent
+    environment:
+      # more options: https://www.jaegertracing.io/docs/1.11/deployment/#all-options-1
+      REPORTER_TYPE: grpc
+      REPORTER_GRPC_HOST_PORT: jaeger-collector:14250
+      PROCESSOR_JAEGER_BINARY_SERVER_HOST_PORT: :6832
+    command: wait.sh http://jaeger-collector:14269 5 20 "jaeger-agent"
+    ports:
+      - "6832:6832" # receiving traces via UDP
+      - "5778:5778" # get sampling strategies
+    networks:
+      - aparnet
+    depends_on:
+      - jaeger-collector
 
   jaeger-collector:
     build: jaeger-collector

jaeger-agent/Dockerfile

@@ -0,0 +1,8 @@
+FROM alpine:3.9.3
+
+# required by wait script
+RUN apk add --no-cache bash curl
+
+COPY jaeger-agent wait.sh /usr/local/bin/
+
+RUN chmod +x /usr/local/bin/wait.sh

jaeger-agent/jaeger-agent

@@ -0,0 +1,36 @@
+#!/bin/bash
+
+# Requires a container with Bash and Curl installed.
+
+is_healthy () {
+	retryInterval=${2:-5}
+	maxAttempts=${3:-1000000}
+
+	i=0
+	while [ $i -lt $maxAttempts ]
+	do
+		status=$(curl -s -L -o /dev/null -w %{http_code} $1)
+
+		# stop trying if we get a success response
+		if [ $status -ge 200 ] && [ $status -lt 300 ]
+		then
+			return 0
+		fi
+		
+		((i++))
+		echo "Attempt $i of $maxAttempts: Endpoint $1 returned code $status. Retrying in $retryInterval seconds."
+		sleep $retryInterval
+	done
+
+	return 1
+}
+
+# args: endpoint, retryInterval (secs), maxAttempts, command
+if is_healthy $1 $2 $3
+then
+	echo "Running command: $4"
+	# vulnerable to input-injection attacts (but I don't care :)
+	eval "$4"
+else
+	echo "Exiting: Cannot run command because health-check failed."
+fi