One of the problems you encounter when you have a lot of verticles to deploy, is how to define dependencies between them, define an order, and organize the configuration.

This project aims to solve those issues through a configuration file where you can define the verticles and the dependencies between them. You can easily create a configuration which will be passed to the verticle.

The configuration file a fairly easy. You define a collection called "verticles" which contains a list of verticles to be deployed. Each definition of a verticle requires a name. This name acts as an ID for references.

There are only two fields related to the logic of the Deployer. You must specify a name. The name is the class which must be available on the classpath.

The seconds important field is "dependsOn". In the list "dependsOn" you can add a list of IDs of verticles which need to be started BEFORE the start of this verticle. The "dependsOn" field is optional. When it is omitted the verticle will start immediately. All the verticles on the same level are started asynchronously. For example, when two verticles do not have a "dependsOn" restriction, they will start at the same moment.

When one verticle does not start, the process is terminated.

{
   "verticles": [
         "mongodb": {
            "worker": true,
            "name": "de.neofonie.verticle.MongoVerticle",
            "instances": 1,
            "multithreaded": false
          },
          "import": {
            "dependsOn": ["mongodb"],
            "name": "de.neofonie.verticle.ImportVerticle"
          },
          "server": {
            "dependsOn": ["mongodb", "import"],
            "name": "de.neofonie.verticle.ServerVerticle"
          }
    ] 
}

All other fields you define are passed into the Verticle-core. They are not sanity checked by the deployer.

Everything which is defined under the name "config" in your verticle, is injected into the config object inside verticle. You find this configuration in context.config().

{
    "verticles": {
        "verticle-simple": {
            "name": "de.neofonie.deployer.TestVerticle2",
            "config": {
                "field2": 300,
                "field3": "text"
            }
        }
    }
}

Sometimes you will have the need to share configuration parameters across more verticles. You can repeat this configuration in every verticle or you can make use of a special construction in the JSON config file. The fields you specify will be available in all verticles. You can overwrite these values in the verticle itself. The configuration of the verticle takes precedence.

{
  "config": {
    "service-name": "my-service",
    "custom-field": {
        "field1": 52428800,
        "field2": "value"
    }
   "verticles": {
        // ....
    }
}

For ease of use, we have constructed a StartVerticle which does the initialization of the DeployerVerticle for you. The StartVerticle also takes care for the destruction of the verticles when a SIGTERM/SIGINT signal is received by the application. This is useful when your application is running in a Docker container and needs to do a graceful shutdown. We have defined an interval of 5 seconds in which the application can shut down gracefully without being terminated. When you need more time to destruct the application you are probably doing something wrong, hence we made it a fixed value. Of course, you can always write your own StartVerticle with your own logic inside.