Having trouble making sense of vert.x config loading - vert.x

Question

I am trying to create a verticle by using a config.json and am not experiencing what I expect by reading the docs. I will attempt to explain the steps I've taken as best I can but I have tried many variations to the startup steps of my verticle, so I may not be 100% accurate. This is using vert.x 3.7.0.
First, I have successfully used my config to launch my verticle when I include the config file in the expected location, conf/config.json:
{
"database" : {
"port" : 5432,
"host" : "127.0.0.1",
"name" : "linked",
"user" : "postgres",
"passwd" : "postgres",
"connectionPoolSize" : 5
},
"chatListener" : {
"port" : 8080,
"host" : "localhost"
}
}
and use the launcher to pass the config to start the verticle (pseudocode):
public static void main(String[] args){
//preprocessing
Launcher.executeCommand("run", "MyVerticle")
...
and
public static void main(String[] args){
//preprocessing
Launcher.executeCommand("run", "MyVerticle -config conf/config.json")
...
both work correctly. My config is loaded I can pull the data from config() inside my verticle:
JsonObject chatDbOpts = new JsonObject().put( "config", config.getJsonObject( "database" ) );
....
But when I pass a file reference that is not the default location to the launcher,
$ java -jar vert.jar -config /path/to/config.json
it ignores it and uses the built-in config, which is empty, ignoring my config. Yet the debug output from the vertx Config loader indicates it is using the default location:
conf/config.json
which it doesn't actually do, because my config file is there. So the config loader isn't loading from the default location when a different config is specified on the CLI.
So I changed the code to digest the config in main and validated the json file can be found and read. Then passed the file reference to the launcher but got the same behaviour. So then I changed to using a DeploymentOptions object with deployVerticle.
Output from my preprocessor steps of loading the config and converting it to a JsonObject:
Command line arguments: [-conf, d:/cygwin64/home/rcoe/conf/config.json]
Launching application with the following config:
{
"database" : {
"port" : 5432,
"host" : "127.0.0.1",
"name" : "linked",
"user" : "postgres",
"passwd" : "postgres",
"connectionPoolSize" : 5
},
"chatListener" : {
"port" : 8080,
"host" : "localhost"
}
}
This JsonObject is used to create a DeploymentOptions reference:
DeploymentOptions options = new DeploymentOptions(jsonCfg);
Vertx.vertx().deployVerticle( getClass().getName(), options );
Didn't work.
So then I tried creating an empty DeploymentOptions reference and setting the config:
DeploymentOptions options = new DeploymentOptions();
Map<String,Object> m = new HashMap<>();
m.put("config", jsonObject);
JsonObject cfg = new JsonObject(m);
options.setConfig( cfg );
Vertx.vertx().deployVerticle( getClass().getName(), options );
which also fails to pass my desired config. Instead, it uses config from the default location.
Here's the output from the verticle's starting up. It is using the conf/config.json file,
Config file path: conf\config.json, format:json
-Dio.netty.buffer.checkAccessible: true
-Dio.netty.buffer.checkBounds: true
Loaded default ResourceLeakDetector: io.netty.util.ResourceLeakDetector#552c2b11
Config options:
{
"port" : 5432,
"host" : "not-a-real-host",
"name" : "linked",
"user" : "postgres",
"passwd" : "postgres",
"connectionPoolSize" : 5
}
versus the config that is given to the DeploymentOptions reference:
Launching application with the following config:
{
"database" : {
"port" : 5432,
"host" : "127.0.0.1",
"name" : "linked",
"user" : "postgres",
"passwd" : "postgres",
"connectionPoolSize" : 5
},
...
Anyway, hope these steps make sense and show I've tried a variety of methods to load custom config. I have seen my config get passed into the vert.x code that is responsible for invoking verticles but by the time my verticle's start() method gets called, my config is gone.
Thanks.

Answer 1

As is usual, authoring a question leads to a better view to the problem. The solution, as I understand it, is to always create a map with a key called "config" and a value of the JsonObject you want to pass.
To deploy:
private void launch( final JsonObject jsonObject )
{
DeploymentOptions options = new DeploymentOptions();
Map<String, Object> m = new HashMap<>();
m.put( "config", jsonObject );
JsonObject cfg = new JsonObject( m );
options.setConfig( cfg );
Vertx.vertx().deployVerticle( MainVerticle.class.getName(), options );
}
#override
public void start( final Future<Void> startFuture )
{
ConfigRetriever cfgRetriever = ConfigRetriever.create( vertx.getDelegate() );
cfgRetriever.getConfig( ar -> {
try {
if( ar.succeeded() ) {
JsonObject config = ar.result();
JsonObject cfg = config.getJsonObject( "config" );
JsonObject chatDbOpts = cfg.getJsonObject( "database" );
LOGGER.debug( "Launching ChatDbServiceVerticle with the following config:\n{}",
chatDbOpts.encodePrettily() );
JsonObject chatHttpOpts = cfg.getJsonObject( "chatListener" );
LOGGER.debug( "Launching HttpServerVerticle with the following config:\n{}",
chatHttpOpts.encodePrettily() );
...
produces the output:
Launching ChatDbServiceVerticle with the following config:
{
"port" : 5432,
"host" : "127.0.0.1",
"name" : "linked",
"user" : "postgres",
"passwd" : "postgres",
"connectionPoolSize" : 5
}
Launching HttpServerVerticle with the following config:
{
"port" : 8080,
"host" : "localhost"
}
But this begs the question as to the point of a DeploymentOptions(JsonObject) constructor if the config() ignores any object that can't be retrieved with a specific key? It required stepping through the debugger to find this. There's no hint of this requirement in the docs, https://vertx.io/blog/vert-x-application-configuration/.