org.graylog.plugins.pipelineprocessor.functions.messages.SetField Maven / Gradle / Ivy

/*
 * Copyright (C) 2020 Graylog, Inc.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the Server Side Public License, version 1,
 * as published by MongoDB, Inc.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * Server Side Public License for more details.
 *
 * You should have received a copy of the Server Side Public License
 * along with this program. If not, see
 * .
 */
package org.graylog.plugins.pipelineprocessor.functions.messages;

import com.google.common.base.Strings;
import org.graylog.plugins.pipelineprocessor.EvaluationContext;
import org.graylog.plugins.pipelineprocessor.ast.functions.AbstractFunction;
import org.graylog.plugins.pipelineprocessor.ast.functions.FunctionArgs;
import org.graylog.plugins.pipelineprocessor.ast.functions.FunctionDescriptor;
import org.graylog.plugins.pipelineprocessor.ast.functions.ParameterDescriptor;
import org.graylog2.plugin.Message;

import java.util.Optional;

import static com.google.common.collect.ImmutableList.of;
import static org.graylog.plugins.pipelineprocessor.ast.functions.ParameterDescriptor.object;
import static org.graylog.plugins.pipelineprocessor.ast.functions.ParameterDescriptor.string;
import static org.graylog.plugins.pipelineprocessor.ast.functions.ParameterDescriptor.type;

public class SetField extends AbstractFunction {

    public static final String NAME = "set_field";

    private final ParameterDescriptor fieldParam;
    private final ParameterDescriptor valueParam;
    private final ParameterDescriptor prefixParam;
    private final ParameterDescriptor suffixParam;
    private final ParameterDescriptor messageParam;
    private final ParameterDescriptor defaultParam;

    public SetField() {
        fieldParam = string("field").description("The new field name").build();
        valueParam = object("value").description("The new field value").build();
        prefixParam = string("prefix").optional().description("The prefix for the field name").build();
        suffixParam = string("suffix").optional().description("The suffix for the field name").build();
        messageParam = type("message", Message.class).optional().description("The message to use, defaults to '$message'").build();
        defaultParam = object("default").optional().description("Used when value not available").build();
    }

    @Override
    public Void evaluate(FunctionArgs args, EvaluationContext context) {
        String field = fieldParam.required(args, context);
        Object value = null;
        try {
            value = valueParam.required(args, context);
        } catch (Exception e) {
            // swallow the exception if there is an available default value;
            if (!args.isPresent("default")) {
                throw e;
            }
        }
        finally {
            if (value == null) {
                value = defaultParam.optional(args, context).orElse(null);
            }
        }

        if (!Strings.isNullOrEmpty(field)) {
            final Message message = messageParam.optional(args, context).orElse(context.currentMessage());
            final Optional prefix = prefixParam.optional(args, context);
            final Optional suffix = suffixParam.optional(args, context);

            if (prefix.isPresent()) {
                field = prefix.get() + field;
            }
            if (suffix.isPresent()) {
                field = field + suffix.get();
            }
            message.addField(field, value);
        }
        return null;
    }

    @Override
    public FunctionDescriptor descriptor() {
        return FunctionDescriptor.builder()
                .name(NAME)
                .returnType(Void.class)
                .params(of(fieldParam,
                        valueParam,
                        prefixParam,
                        suffixParam,
                        messageParam,
                        defaultParam))
                        .description("Sets a new field in a message")
                        .build();
    }
}