ranger插件的初始化

随手记录, 主要都是在配置文件里写好类名, 然后classFor读取记载.

ranger init chained plugin

利用classLoader, 实例化配置里的插件.

public class RangerBasePlugin {

    this.chainedPlugins = initChainedPlugins();

    private List<RangerChainedPlugin> initChainedPlugins() {
        List<RangerChainedPlugin> ret                      = new ArrayList<>();
        String                    chainedServicePropPrefix = pluginConfig.getPropertyPrefix() + ".chained.services";

        for (String chainedService : StringUtil.toList(pluginConfig.get(chainedServicePropPrefix))) {
            if (StringUtils.isBlank(chainedService)) {
                continue;
            }

            String className = pluginConfig.get(chainedServicePropPrefix + "." + chainedService + ".impl");

            if (StringUtils.isBlank(className)) {
                LOG.error("Ignoring chained service " + chainedService + ": no impl class specified");

                continue;
            }

            try {
                @SuppressWarnings("unchecked")
                Class<RangerChainedPlugin> pluginClass   = (Class<RangerChainedPlugin>) Class.forName(className);
                RangerChainedPlugin        chainedPlugin = pluginClass.getConstructor(RangerBasePlugin.class, String.class).newInstance(this, chainedService);

                ret.add(chainedPlugin);
            } catch (Throwable t) {
                LOG.error("initChainedPlugins(): error instantiating plugin impl " + className, t);
            }
        }

        return ret;
    }
}

audit provider

audit provider 插件, 也是靠配置里名称进行实例化

package org.apache.ranger.audit.provider;


    private AuditHandler getProviderFromConfig(Properties props,
            String propPrefix, String providerName, AuditHandler consumer) {
        AuditHandler provider = null;
        String className = MiscUtil.getStringProperty(props, propPrefix + "."
                + BaseAuditHandler.PROP_CLASS_NAME);
        if (className != null && !className.isEmpty()) {
            try {
                Class<?> handlerClass = Class.forName(className);
                if (handlerClass.isAssignableFrom(AuditQueue.class)) {
                    // Queue class needs consumer
                    handlerClass.getDeclaredConstructor(AuditHandler.class)
                            .newInstance(consumer);
                } else {
                    provider = (AuditHandler) Class.forName(className)
                            .newInstance();
                }
            } catch (Exception e) {
                LOG.error("Can't instantiate audit class for providerName="
                        + providerName + ", className=" + className
                        + ", propertyPrefix=" + propPrefix, e);
            }
        }
    }