= Maven verticle factory

The Maven verticle factory is an implementation of verticle factory loading a service dynamically from a Maven
repository at run-time. It's useful if you don't want to package all your service dependencies at build-time into
your application, but would rather install and deploy them dynamically at run-time when they are requested.

## Usage

Vert.x picks up `VerticleFactory` implementations from the classpath, so you just need to make sure the
vertx-maven-service-factory jar file on the classpath. First you need to add the Maven verticle factory to your application's
classpath. If you are using a fat jar, you can use the following dependencies:

* Maven (in your `pom.xml`):

[source,xml,subs="+attributes"]
----
<dependency>
 <groupId>io.vertx</groupId>
 <artifactId>vertx-maven-service-factory</artifactId>
 <version>3.9.12</version>
</dependency>
----

* Gradle (in your `build.gradle` file):

[source,groovy,subs="+attributes"]
----
compile 'io.vertx:vertx-maven-service-factory:3.9.12'
----

This `VerticleFactory` uses the prefix `maven:` to select it when deploying services.
The service identifier is made up of the Maven co-ordinates of the artifact that contains the service, e.g.
`com.mycompany:main-services:1.2` followed by a double colon `::` followed by the service name. The service name is
used to find the service descriptor file inside the artifact which is named by the service name with a `.json`
extension. This is explained in the the
link:http://vertx.io/docs/vertx-service-factory/java[vert.x service factory documentation].

For example, to deploy a service that exists in Maven artifact `com.mycompany:my-artifact:1.2` called `my-service` you
would use the string `maven:com.mycompany:main-services:1.2::my-service`. Given this string, the verticle factory

1. uses the Aether client try and locate the artifact `com.mycompany:my-artifact:1.2` and all its dependencies in
the configured Maven repositories and download and install it locally if it's not already installed.
2. constructs a classpath including all those artifacts and creates a classloader with that classpath
3. service using the link:http://vertx.io/docs/vertx-service-factory/java[vert.x service factory].

Note that if the current Vert.x classpath contains already an artifact, then this dependency will not be
overridden and will be effectively used. Vert.x does not attempt to make some class loading magic, conflicts
should be resolved by modifying the Vert.x classpath to not contain this dependency.

The Service Verticle Factory will look for a descriptor file called `my-service.json` (in the previous example) on
the constructed classpath to actually load the service.

Given a service identifier the service can be deployed programmatically e.g.:

[source,java]
----
vertx.deployVerticle("maven:com.mycompany:my-artifact:1.2::my-service", options);
----

Or can be deployed on the command line with:

---
vertx run maven:com.mycompany:my-artifact:1.2::my-service
---

The service name (`my-service`) can be omitted when the _META-INF/MANIFEST_ in the jar containing the
service contains a `Main-Verticle` entry that declares the verticle to run:

[source,java]
----
vertx.deployVerticle("maven:com.mycompany:my-artifact:1.2", options);
----

And the manifest contains:

----
Main-Verticle: service:my-service
----


## Declaring the Verticle Factory programmatically

You can also declare the verticle factory programmatically:

[source,java]
----
vertx.registerVerticleFactory(new MavenVerticleFactory());
----

## Configuring repositories

The Maven local repository location can be configured using the `vertx.maven.localRepo` system property - this should
point to the local repository directory on disc. The default value is: `{user.home}/.m2/repository`

The list of remote repositories can be configured using the `vertx.maven.remoteRepos` system property - this should
contain a*space** separated list of urls to the remote repositories. The default value is
`https://repo.maven.apache.org/maven2/ https://oss.sonatype.org/content/repositories/snapshots/`

### Programmatically

You can also configure the repositories programmatically by passing a `link:../../apidocs/io/vertx/maven/ResolverOptions.html[ResolverOptions]`
object to the constructor of the `link:../../apidocs/io/vertx/maven/MavenVerticleFactory.html[MavenVerticleFactory]`:

[source,java]
----
vertx.registerVerticleFactory(new MavenVerticleFactory(
    new ResolverOptions()
        .setLocalRepository(local)
        .setRemoteRepositories(remotes))
);
----

## Remote repository access through authenticated https

You can specify https URLs for remote repositories, the client will uses the JSSE system properties
configuration. It can be achieved via JVM system properties, you can read more at
http://maven.apache.org/guides/mini/guide-repository-ssl.html.

### Using system properties

It can configured when running the JVM: for instance:

----
java -jar my-fat-jar -Djavax.net.ssl.trustStore=/my_trust_store.jks -Djavax.net.ssl.trustStorePassword=somepassword
----

### Programmatically

To configure the HTTPS property, use:

[source,java]
----
System.setProperty("javax.net.ssl.trustStore", "/my_trust_store.jks");
System.setProperty("javax.net.ssl.trustStorePassword", "somepassword");
----

Note that programmatic configuration must be done before using the underlying Aether client (so before
instantiating the `link:../../apidocs/io/vertx/maven/MavenVerticleFactory.html[MavenVerticleFactory]`.

## Remote repository access through proxies

### Using system properties

Repositories can be accessed using an http proxy using the `vertx.maven.httpProxy` and `vertx.maven.httpsProxy`.
The former configures a proxy for remote http repositories and the later configures a proxy for remote http repositories.

### Programmatically

You can also configure the repositories programmatically using the
`link:../../apidocs/io/vertx/maven/ResolverOptions.html#setHttpProxy-java.lang.String-[setHttpProxy]` and
`link:../../apidocs/io/vertx/maven/ResolverOptions.html#setHttpsProxy-java.lang.String-[setHttpsProxy]`:

[source,java]
----
vertx.registerVerticleFactory(new MavenVerticleFactory(
    new ResolverOptions().setHttpProxy(proxy))
);
----

## Configuring authentication

Basic authentication can be achieved by adding a username and/or password in the repository or proxy configuration.
For instance `http://julien:secret@myrepository.com/` will configure to use `julien` username and `secret`
password if the remote server needs authentication. Proxies are also supported.

## Configuring Remote Snapshot Refresh Policy

By default _SNAPSHOT_ dependencies are updated once a day. This behavior can be modified using the system property
`vertx.maven.remoteSnapshotPolicy`. This can be set to `always` to ensure _SNAPSHOT_ dependencies are updated every
time, `daily` to update just once a day, which is the default, or to `never` to ensure they are never updated.

It can also be set to `interval:X` where `X` is the number of minutes to allow before updating a _SNAPSHOT_
dependency.

The refresh policy can also be configured from the `link:../../apidocs/io/vertx/maven/ResolverOptions.html[ResolverOptions]`:

[source,java]
----
vertx.registerVerticleFactory(new MavenVerticleFactory(
    new ResolverOptions().setRemoteSnapshotPolicy("never"))
);
----

## Customizing the resolver

You can create an instance of
`link:../../apidocs/io/vertx/maven/MavenVerticleFactory.html[MavenVerticleFactory]` using your own `link:../../apidocs/io/vertx/maven/Resolver.html[Resolver]`:

[source,java]
----
vertx.registerVerticleFactory(new MavenVerticleFactory(myResolver)
);
----