com.netflix.spinnaker.orca.pipelinetemplate.v1schema.render.HandlebarsRenderer.java Source code

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Here is the source code for com.netflix.spinnaker.orca.pipelinetemplate.v1schema.render.HandlebarsRenderer.java

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/*
 * Copyright 2017 Netflix, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.netflix.spinnaker.orca.pipelinetemplate.v1schema.render;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.github.jknack.handlebars.Context;
import com.github.jknack.handlebars.EscapingStrategy;
import com.github.jknack.handlebars.Handlebars;
import com.github.jknack.handlebars.Template;
import com.netflix.spinnaker.orca.pipelinetemplate.exceptions.TemplateRenderException;
import com.netflix.spinnaker.orca.pipelinetemplate.v1schema.render.helper.ConditionHelper;
import com.netflix.spinnaker.orca.pipelinetemplate.v1schema.render.helper.JsonHelper;
import com.netflix.spinnaker.orca.pipelinetemplate.v1schema.render.helper.ModuleHelper;
import org.apache.commons.lang3.math.NumberUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.Collection;
import java.util.HashMap;

/**
 * Runs a two-phase render, first to process the handlebars template, then a second
 * phase to convert the resulted JSON string into a Java object.
 */
public class HandlebarsRenderer implements Renderer {

    private final Logger log = LoggerFactory.getLogger(getClass());

    Handlebars handlebars;

    ObjectMapper pipelineTemplateObjectMapper;

    public HandlebarsRenderer(ObjectMapper pipelineTemplateObjectMapper) {
        this.pipelineTemplateObjectMapper = pipelineTemplateObjectMapper;

        handlebars = new Handlebars().with(EscapingStrategy.NOOP)
                .registerHelper("json", new JsonHelper(pipelineTemplateObjectMapper))
                .registerHelper("module", new ModuleHelper(this, pipelineTemplateObjectMapper));
        ConditionHelper.register(handlebars);
    }

    @Override
    public String render(String template, RenderContext configuration) {
        log.debug("rendering '" + template + "'");

        Template tmpl;
        try {
            tmpl = handlebars.compileInline(template);
        } catch (IOException e) {
            throw new TemplateRenderException("could not compile handlebars template", e);
        }

        Context context = Context.newContext(configuration);

        try {
            return tmpl.apply(context);
        } catch (IOException e) {
            throw new TemplateRenderException("could not apply context to template", e);
        }
    }

    @Override
    public Object renderGraph(String template, RenderContext context) {
        String rendered = render(template, context);

        // Short-circuit primitive values.
        // TODO rz - having trouble getting jackson to parse primitive values outside of unit tests
        if (NumberUtils.isNumber(rendered)) {
            if (rendered.contains(".")) {
                return NumberUtils.createDouble(rendered);
            }
            try {
                return NumberUtils.createInteger(rendered);
            } catch (NumberFormatException ignored) {
                return NumberUtils.createLong(rendered);
            }
        } else if (rendered.equals("true") || rendered.equals("false")) {
            return Boolean.parseBoolean(rendered);
        } else if (!rendered.startsWith("{") && !rendered.startsWith("[")) {
            return rendered;
        }

        JsonNode node;
        try {
            node = pipelineTemplateObjectMapper.readTree(rendered);
        } catch (IOException e) {
            throw new TemplateRenderException("template produced invalid json", e);
        }

        try {
            if (node.isArray()) {
                return pipelineTemplateObjectMapper.readValue(rendered, Collection.class);
            }
            if (node.isObject()) {
                return pipelineTemplateObjectMapper.readValue(rendered, HashMap.class);
            }
            if (node.isBoolean()) {
                return Boolean.parseBoolean(node.asText());
            }
            if (node.isDouble()) {
                return node.doubleValue();
            }
            if (node.canConvertToInt()) {
                return node.intValue();
            }
            if (node.canConvertToLong()) {
                return node.longValue();
            }
            if (node.isTextual()) {
                return node.textValue();
            }
            if (node.isNull()) {
                return null;
            }
        } catch (IOException e) {
            throw new TemplateRenderException("template produced invalid json", e);
        }

        throw new TemplateRenderException("unknown rendered object type");
    }
}