org.springframework.cloud.config.client.ConfigServicePropertySourceLocator.java Source code

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/*
 * Copyright 2013-2014 the original author or 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 org.springframework.cloud.config.client;

import java.io.IOException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.cloud.bootstrap.config.PropertySourceLocator;
import org.springframework.cloud.config.environment.Environment;
import org.springframework.cloud.config.environment.PropertySource;
import org.springframework.core.annotation.Order;
import org.springframework.core.env.CompositePropertySource;
import org.springframework.core.env.MapPropertySource;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpRequest;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.http.client.ClientHttpRequestExecution;
import org.springframework.http.client.ClientHttpRequestInterceptor;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.retry.annotation.Retryable;
import org.springframework.util.Base64Utils;
import org.springframework.util.StringUtils;
import org.springframework.web.client.HttpClientErrorException;
import org.springframework.web.client.HttpServerErrorException;
import org.springframework.web.client.RestTemplate;

import static org.springframework.cloud.config.client.ConfigClientProperties.STATE_HEADER;
import static org.springframework.cloud.config.client.ConfigClientProperties.TOKEN_HEADER;

/**
 * @author Dave Syer
 *
 */
@Order(0)
public class ConfigServicePropertySourceLocator implements PropertySourceLocator {

    private static Log logger = LogFactory.getLog(ConfigServicePropertySourceLocator.class);

    private RestTemplate restTemplate;
    private ConfigClientProperties defaultProperties;

    public ConfigServicePropertySourceLocator(ConfigClientProperties defaultProperties) {
        this.defaultProperties = defaultProperties;
    }

    @Override
    @Retryable(interceptor = "configServerRetryInterceptor")
    public org.springframework.core.env.PropertySource<?> locate(
            org.springframework.core.env.Environment environment) {
        ConfigClientProperties properties = this.defaultProperties.override(environment);
        CompositePropertySource composite = new CompositePropertySource("configService");
        RestTemplate restTemplate = this.restTemplate == null ? getSecureRestTemplate(properties)
                : this.restTemplate;
        Exception error = null;
        String errorBody = null;
        logger.info("Fetching config from server at: " + properties.getRawUri());
        try {
            String[] labels = new String[] { "" };
            if (StringUtils.hasText(properties.getLabel())) {
                labels = StringUtils.commaDelimitedListToStringArray(properties.getLabel());
            }

            String state = ConfigClientStateHolder.getState();

            // Try all the labels until one works
            for (String label : labels) {
                Environment result = getRemoteEnvironment(restTemplate, properties, label.trim(), state);
                if (result != null) {
                    logger.info(String.format(
                            "Located environment: name=%s, profiles=%s, label=%s, version=%s, state=%s",
                            result.getName(),
                            result.getProfiles() == null ? "" : Arrays.asList(result.getProfiles()),
                            result.getLabel(), result.getVersion(), result.getState()));

                    for (PropertySource source : result.getPropertySources()) {
                        @SuppressWarnings("unchecked")
                        Map<String, Object> map = (Map<String, Object>) source.getSource();
                        composite.addPropertySource(new MapPropertySource(source.getName(), map));
                    }

                    if (StringUtils.hasText(result.getState()) || StringUtils.hasText(result.getVersion())) {
                        HashMap<String, Object> map = new HashMap<>();
                        putValue(map, "config.client.state", result.getState());
                        putValue(map, "config.client.version", result.getVersion());
                        composite.addFirstPropertySource(new MapPropertySource("configClient", map));
                    }
                    return composite;
                }
            }
        } catch (HttpServerErrorException e) {
            error = e;
            if (MediaType.APPLICATION_JSON.includes(e.getResponseHeaders().getContentType())) {
                errorBody = e.getResponseBodyAsString();
            }
        } catch (Exception e) {
            error = e;
        }
        if (properties.isFailFast()) {
            throw new IllegalStateException(
                    "Could not locate PropertySource and the fail fast property is set, failing", error);
        }
        logger.warn("Could not locate PropertySource: "
                + (errorBody == null ? error == null ? "label not found" : error.getMessage() : errorBody));
        return null;

    }

    private void putValue(HashMap<String, Object> map, String key, String value) {
        if (StringUtils.hasText(value)) {
            map.put(key, value);
        }
    }

    private Environment getRemoteEnvironment(RestTemplate restTemplate, ConfigClientProperties properties,
            String label, String state) {
        String path = "/{name}/{profile}";
        String name = properties.getName();
        String profile = properties.getProfile();
        String token = properties.getToken();
        String uri = properties.getRawUri();

        Object[] args = new String[] { name, profile };
        if (StringUtils.hasText(label)) {
            args = new String[] { name, profile, label };
            path = path + "/{label}";
        }
        ResponseEntity<Environment> response = null;

        try {
            HttpHeaders headers = new HttpHeaders();
            if (StringUtils.hasText(token)) {
                headers.add(TOKEN_HEADER, token);
            }
            if (StringUtils.hasText(state)) { //TODO: opt in to sending state?
                headers.add(STATE_HEADER, state);
            }
            final HttpEntity<Void> entity = new HttpEntity<>((Void) null, headers);
            response = restTemplate.exchange(uri + path, HttpMethod.GET, entity, Environment.class, args);
        } catch (HttpClientErrorException e) {
            if (e.getStatusCode() != HttpStatus.NOT_FOUND) {
                throw e;
            }
        }

        if (response == null || response.getStatusCode() != HttpStatus.OK) {
            return null;
        }
        Environment result = response.getBody();
        return result;
    }

    public void setRestTemplate(RestTemplate restTemplate) {
        this.restTemplate = restTemplate;
    }

    private RestTemplate getSecureRestTemplate(ConfigClientProperties client) {
        SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
        requestFactory.setReadTimeout((60 * 1000 * 3) + 5000); //TODO 3m5s, make configurable?
        RestTemplate template = new RestTemplate(requestFactory);
        String password = client.getPassword();
        if (password != null) {
            template.setInterceptors(Arrays.<ClientHttpRequestInterceptor>asList(
                    new BasicAuthorizationInterceptor(client.getUsername(), password)));
        }
        return template;
    }

    private static class BasicAuthorizationInterceptor implements ClientHttpRequestInterceptor {

        private final String username;

        private final String password;

        public BasicAuthorizationInterceptor(String username, String password) {
            this.username = username;
            this.password = (password == null ? "" : password);
        }

        @Override
        public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution)
                throws IOException {
            byte[] token = Base64Utils.encode((this.username + ":" + this.password).getBytes());
            request.getHeaders().add("Authorization", "Basic " + new String(token));
            return execution.execute(request, body);
        }

    }

}