Allow overriding forwading host through env variable

[MansurAshraf]

Genie allows overriding forwarding port through genie.jobs.forwarding.port, it should allow the same for forwarding host as on some Kubernetes clusters InetAddress.getLocalHost().getCanonicalHostName() returns a hostname that is not DNS resolvable.

example:

  public static String getHostname() throws UnknownHostException {
        final String hostname;
        if (StringUtils.isNotBlank(System.getenv("genie.jobs.forwarding.host"))) {
            hostname = System.getenv("genie.jobs.forwarding.host");
        } else if (AwsCloudEnvironmentCheckUtils.isRunningOnCloudEnvironment()) {
            hostname = EC2MetadataUtils.getPrivateIpAddress();
        } else {
            // Fallback if not on AWS
            hostname = InetAddress.getLocalHost().getCanonicalHostName();
        }

        if (StringUtils.isBlank(hostname)) {
            throw new IllegalStateException("Unable to create a Genie Host Info instance as hostname is blank");
        }

        return hostname;
    }

[mprimi]

Hello @MansurAshraf

If you want the hostname stored in the database (for routing, including forwarding) to be computed with a different strategy than the one we currently use, you can do so by providing your own GenieHostInfo bean.