zipkin.server.ZipkinUiConfiguration Maven / Gradle / Ivy
/**
* Copyright 2015-2016 The OpenZipkin Authors
*
* 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 zipkin.server;
import java.util.concurrent.TimeUnit;
import javax.servlet.http.HttpServletRequest;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.autoconfigure.condition.ConditionalOnResource;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.core.io.Resource;
import org.springframework.http.CacheControl;
import org.springframework.http.ResponseEntity;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.filter.CharacterEncodingFilter;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import static org.springframework.http.MediaType.APPLICATION_JSON_VALUE;
import static org.springframework.web.bind.annotation.RequestMethod.GET;
/**
* Zipkin-UI is a single-page application that reads configuration from /config.json.
*
* When looking at a trace, the browser is sent to the path "/traces/{id}". For the single-page
* app to serve that route, the server needs to forward the request to "/index.html". The same
* forwarding applies to "/dependencies" and any other routes the UI controls.
*
*
Under the scenes the JavaScript code looks at {@code window.location} to figure out what the
* UI should do. This is handled by a route api defined in the crossroads library.
*
*
Caching
* This includes a hard-coded cache policy, consistent with zipkin-scala.
*
* - 1 minute for index.html
* - 10 minute for /config.json
* - 365 days for hashed resources (ex /app-e12b3bbb7e5a572f270d.min.js)
*
* Since index.html links to hashed resource names, any change to it will orphan old resources.
* That's why hashed resource age can be 365 days.
*/
@Configuration
@EnableConfigurationProperties(ZipkinUiProperties.class)
@RestController
@ConditionalOnResource(resources = "classpath:zipkin-ui") // from io.zipkin:zipkin-ui
public class ZipkinUiConfiguration extends WebMvcConfigurerAdapter {
@Autowired
ZipkinUiProperties ui;
@Value("classpath:zipkin-ui/index.html")
Resource indexHtml;
@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
registry.addResourceHandler("/**")
.addResourceLocations("classpath:/zipkin-ui/")
.setCachePeriod((int) TimeUnit.DAYS.toSeconds(365));
}
/**
* This opts out of adding charset to png resources.
*
* By default, {@linkplain CharacterEncodingFilter} adds a charset qualifier to all resources,
* which helps, as javascript assets include extended character sets. However, the filter also
* adds charset to well-known binary ones like png. This creates confusing content types, such as
* "image/png;charset=UTF-8".
*
* See https://github.com/spring-projects/spring-boot/issues/5459
*/
@Bean
@Order(Ordered.HIGHEST_PRECEDENCE)
public CharacterEncodingFilter characterEncodingFilter() {
CharacterEncodingFilter filter = new CharacterEncodingFilter() {
@Override
protected boolean shouldNotFilter(HttpServletRequest request) {
return request.getServletPath().endsWith(".png");
}
};
filter.setEncoding("UTF-8");
filter.setForceEncoding(true);
return filter;
}
@RequestMapping(value = "/config.json", method = GET, produces = APPLICATION_JSON_VALUE)
public ResponseEntity serveUiConfig() {
return ResponseEntity.ok()
.cacheControl(CacheControl.maxAge(10, TimeUnit.MINUTES))
.body(ui);
}
@RequestMapping(value = "/index.html", method = GET)
public ResponseEntity serveIndex() {
return ResponseEntity.ok()
.cacheControl(CacheControl.maxAge(1, TimeUnit.MINUTES))
.body(indexHtml);
}
/**
* This cherry-picks well-known routes the single-page app serves, and forwards to that as opposed
* to returning a 404.
*/
// TODO This approach requires maintenance when new UI routes are added. Change to the following:
// If the path is a a file w/an extension, treat normally.
// Otherwise instead of returning 404, forward to the index.
// See https://github.com/twitter/finatra/blob/458c6b639c3afb4e29873d123125eeeb2b02e2cd/http/src/main/scala/com/twitter/finatra/http/response/ResponseBuilder.scala#L321
@RequestMapping(value = {"/", "/traces/{id}", "/dependency"}, method = GET)
public ModelAndView forwardUiEndpoints(ModelMap model) {
// Note: RequestMapping "/" requires us to use ModelAndView result vs just a string.
// When "/" is mapped, the server literally returns "forward:/index.html" vs forwarding.
return new ModelAndView("forward:/index.html", model);
}
}