This app is calling a number of remote services for their Spring Boot Actuator health endpoints to aggregate a combined readiness state. It includes a build process for creating a Docker image for easy execution.
The app offers two modes of operation: command line interface (cli) or web interface (dashboard).
In cli mode it prints out the readiness check results to the console as a YAML document.
In dashboard mode it starts as a daemon and offers an HTTP port (default: 2112) for HTML and JSON results.
The app uses externalized configuration for setting up the remote services to lookup.
Put a configuration file specific to the target platform as a YAML document named application-${platform}.yml into the local folder ./config,
where ${platform} is an arbitrary name identifying your target. See ./config/application-example.com.yml as a reference.
You specify what platform to use by the configuration property called platform.
This can be introduced as a Java System Property (-Dplatform=example.com),
environment variable (PLATFORM=example.com) or Java command argument (--platform=example.com).
The supported configuration options are:
readiness:
connectionTimeout: 100
readTimeout: 200
connectionRequestTimeout: 500
services:
- service: 'users'
uri: 'https://example.com/users/health.json'
- service: 'items'
uri: 'https://example.com/items/health.json'
If your services use self-signed SSL certificates, you need to relax the security of this app:
spring:
profiles:
include: 'insecure'
readiness:
services:
- service: 'users'
uri: 'https://example.com/users/health.json'
Since the ./config directory is not part of the resulting Docker image, you need to mount it
into the running Docker container as a volume. See docker-compose.yml how to do this.
In dashboard mode you can view the combined readiness check result presented as a single HTML page.
Append a query parameter ?refresh=5 to let your browser automatically refresh the output every 5 seconds.
Sorting of underlying health check results is done by appending one or more query parameters sort.
Supported values are:
&sort=service,ASC&sort=service,DESC&sort=status,ASC&sort=status,DESC&sort=totalTimeMillis,ASC&sort=totalTimeMillis,DESC
Default sort direction is &sort=service,ASC;
if you omit the comma-separted direction it will default to ASC.
You can use docker-compose to start the app for a specific target platform:
$ docker-compose run -d --service-ports --name readiness_dashboard dashboard --platform=example.com
$ open http://192.168.99.100:2112/readiness.html?refresh=5
$ docker logs -f readiness_dashboard
The REST endpoint returns a JSON document and can be accessed using a different URI:
$ http http://192.168.99.100:2112/readiness.json
HTTP/1.1 200
Content-Type: application/json;charset=UTF-8
Date: Fri, 10 Mar 2017 08:57:06 GMT
Transfer-Encoding: chunked
{
"status": "UP",
"readiness": {
"platform": "example.com",
"status": "UP",
"totalTimeMillis": 268
"users": {
"application": {
"status": "UP"
},
"hystrix": {
"status": "UP"
},
"refreshScope": {
"status": "UP"
},
"status": "UP",
"totalTimeMillis": 24,
"uri": "https://example.com/users/health.json"
},
"items": {
"db": {
"database": "MySQL",
"hello": 1,
"status": "UP"
},
"rabbit": {
"status": "UP",
"version": "3.5.8"
},
"refreshScope": {
"status": "UP"
},
"status": "UP",
"totalTimeMillis": 189,
"uri": "https://example.com/items/health.json"
}
}
}
In cli mode the app executes a single run of the combined readiness check
and prints the resulting YAML document to stdout.
You can use docker-compose to start the app for a specific target platform:
$ docker-compose run --rm --name readiness_cli cli --platform=example.com
Starting ngreadiness_gradle_1
Picked up JAVA_TOOL_OPTIONS: -Xmx256m -Xss512k -Dfile.encoding=UTF-8 -XX:+UseCompressedOops -XX:+PrintCommandLineFlags
-XX:InitialHeapSize=130683392 -XX:MaxHeapSize=268435456 -XX:+PrintCommandLineFlags -XX:ThreadStackSize=512 -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseParallelGC
09:57:31.035 [main] DEBUG org.springframework.core.env.PropertySourcesPropertyResolver - Found key 'logging.pattern.console' in [applicationConfigurationProperties] with type [String]
---
readiness:
status: "UP"
platform: "example.com"
totalTimeMillis: 795
users:
status: "UP"
uri: "https://example.com/users/health.json"
totalTimeMillis: 50
application:
status: "UP"
refreshScope:
status: "UP"
hystrix:
status: "UP"
items:
status: "UP"
uri: "https://example.com/items/health.json"
totalTimeMillis: 656
rabbit:
status: "UP"
version: "3.5.8"
db:
status: "UP"
database: "MySQL"
hello: 1
refreshScope:
status: "UP"
Sometimes it's difficult to identify why a desired configuration option is not being applied. In this case increase the log level to find out which configuration files are read on app startup:
$ docker-compose run --rm cli --logging.level.org.springframework.boot.context.config.ConfigFileApplicationListener=TRACE --platform=example.com | grep "profiles\|Loaded\|empty"
Starting ngreadiness_gradle_1
Activated profiles cli
Loaded config file 'jar:file:/root/app.jar!/BOOT-INF/classes!/application.yml' (classpath:/application.yml)
Loaded config file 'file:./config/application-example.com.yml' (file:./config/application-example.com.yml)
Skipped (empty) config file 'file:./config/application-example.com.yml' (file:./config/application-example.com.yml) for profile example.com
Skipped (empty) config file 'jar:file:/root/app.jar!/BOOT-INF/classes!/application.yml' (classpath:/application.yml) for profile example.com
Skipped (empty) config file 'file:./config/application-example.com.yml' (file:./config/application-example.com.yml) for profile insecure
Skipped (empty) config file 'jar:file:/root/app.jar!/BOOT-INF/classes!/application.yml' (classpath:/application.yml) for profile insecure
Skipped (empty) config file 'file:./config/application-example.com.yml' (file:./config/application-example.com.yml) for profile cli
Loaded config file 'jar:file:/root/app.jar!/BOOT-INF/classes!/application-cli.yml' (classpath:/application-cli.yml)
Skipped (empty) config file 'jar:file:/root/app.jar!/BOOT-INF/classes!/application-cli.yml' (classpath:/application-cli.yml) for profile cli
Skipped (empty) config file 'jar:file:/root/app.jar!/BOOT-INF/classes!/application.yml' (classpath:/application.yml) for profile cli