25662474597

Committed 11 May 2026 09:40AM UTC coverage: 53.432% (+0.1%) from 53.324%

Build # 25662474597

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github

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web-flow

Commit Message

Merge pull request #81 from Nanopublication/feature/query-status-aware-routing

feat(services): gate query instances on Nanopub-Query-Status header

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80.74

src/main/java/org/nanopub/extra/services/QueryCall.java

package org.nanopub.extra.services;

import org.apache.http.Header;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.util.EntityUtils;
import org.nanopub.NanopubUtils;
import org.nanopub.vocabulary.NPS;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Date;
import java.util.LinkedList;
import java.util.List;
import java.util.Locale;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/**
 * Second-generation query API call.
 */
public class QueryCall {

    private static final int DEFAULT_PARALLEL_CALL_COUNT = 2;

    /**
     * System property setting how many query API instances to call in parallel.
     * Must be {@code >= 1}; defaults to {@value #DEFAULT_PARALLEL_CALL_COUNT}.
     * Env var {@code NANOPUB_QUERY_PARALLEL_CALL_COUNT} also accepted.
     */
    public static final String PARALLEL_CALL_COUNT_PROPERTY = "nanopub.query.parallel-call-count";

    /**
     * Environment variable equivalent of {@link #PARALLEL_CALL_COUNT_PROPERTY}.
     */
    public static final String PARALLEL_CALL_COUNT_ENV = "NANOPUB_QUERY_PARALLEL_CALL_COUNT";

    private static int maxRetryCount = 3;
    private static final Logger logger = LoggerFactory.getLogger(QueryCall.class);

    /**
     * Returns the number of query API instances to call in parallel, resolved
     * (in order) from {@link #PARALLEL_CALL_COUNT_PROPERTY},
     * {@link #PARALLEL_CALL_COUNT_ENV}, or the default of
     * {@value #DEFAULT_PARALLEL_CALL_COUNT}. Invalid values are ignored.
     *
     * @return the parallel call count (always {@code >= 1})
     */
    public static int getParallelCallCount() {
        String value = System.getProperty(PARALLEL_CALL_COUNT_PROPERTY);
        if (value == null || value.isEmpty()) value = System.getenv(PARALLEL_CALL_COUNT_ENV);
        if (value != null && !value.trim().isEmpty()) {
            try {
                int n = Integer.parseInt(value.trim());
                if (n >= 1) return n;
                logger.warn("Ignoring {}={}: must be >= 1", PARALLEL_CALL_COUNT_PROPERTY, value);
            } catch (NumberFormatException ex) {
                logger.warn("Ignoring {}={}: not an integer", PARALLEL_CALL_COUNT_PROPERTY, value);
            }
        }
        return DEFAULT_PARALLEL_CALL_COUNT;
    }

    /**
     * HTTP response header carrying the query instance's sync state.
     * See nanopub-query's {@code StatusController}.
     */
    public static final String QUERY_STATUS_HEADER = "Nanopub-Query-Status";

    /**
     * System property setting the cool-down (in seconds) before a query instance
     * evicted for non-ready status is re-considered. Default
     * {@value #DEFAULT_EVICTION_COOLDOWN_SECONDS}. Env var
     * {@code NANOPUB_QUERY_EVICTION_COOLDOWN_SECONDS} also accepted.
     */
    public static final String EVICTION_COOLDOWN_PROPERTY = "nanopub.query.eviction-cooldown-seconds";

    /**
     * Environment variable equivalent of {@link #EVICTION_COOLDOWN_PROPERTY}.
     */
    public static final String EVICTION_COOLDOWN_ENV = "NANOPUB_QUERY_EVICTION_COOLDOWN_SECONDS";

    private static final int DEFAULT_EVICTION_COOLDOWN_SECONDS = 300;

    private static final ConcurrentMap<String, Long> evictedUntil = new ConcurrentHashMap<>();

    /**
     * Returns the eviction cool-down in milliseconds, resolved from
     * {@link #EVICTION_COOLDOWN_PROPERTY}, {@link #EVICTION_COOLDOWN_ENV},
     * or the default of {@value #DEFAULT_EVICTION_COOLDOWN_SECONDS} seconds.
     */
    public static long getEvictionCooldownMillis() {
        String value = System.getProperty(EVICTION_COOLDOWN_PROPERTY);
        if (value == null || value.isEmpty()) value = System.getenv(EVICTION_COOLDOWN_ENV);
        if (value != null && !value.trim().isEmpty()) {
            try {
                long n = Long.parseLong(value.trim());
                if (n >= 0) return n * 1000L;
                logger.warn("Ignoring {}={}: must be >= 0", EVICTION_COOLDOWN_PROPERTY, value);
            } catch (NumberFormatException ex) {
                logger.warn("Ignoring {}={}: not a number", EVICTION_COOLDOWN_PROPERTY, value);
            }
        }
        return DEFAULT_EVICTION_COOLDOWN_SECONDS * 1000L;
    }

    /**
     * Returns true if the response's {@link #QUERY_STATUS_HEADER} signals a
     * fully-synced state ({@code READY} or {@code LOADING_UPDATES}). Missing
     * header is treated as ready for backwards compatibility with older
     * query instances.
     */
    static boolean isReadyStatus(HttpResponse resp) {
        Header h = resp.getFirstHeader(QUERY_STATUS_HEADER);
        if (h == null) return true;
        String v = h.getValue();
        if (v == null || v.isEmpty()) return true;
        String upper = v.toUpperCase(Locale.ROOT);
        return upper.equals("READY") || upper.equals("LOADING_UPDATES");
    }

    private static void evict(String apiUrl, String reason) {
        long until = System.currentTimeMillis() + getEvictionCooldownMillis();
        evictedUntil.put(apiUrl, until);
        logger.warn("Evicting Nanopub Query instance {} until {} ({})", apiUrl, new Date(until), reason);
    }

    private static List<String> filterEvicted(List<String> instances) {
        long now = System.currentTimeMillis();
        List<String> result = new ArrayList<>(instances.size());
        for (String url : instances) {
            Long until = evictedUntil.get(url);
            if (until == null || until <= now) result.add(url);
        }
        return result;
    }

    /**
     * Run a query call with the given query ID and parameters.
     *
     * @param queryRef the reference to the query to run
     * @return the HTTP response from the query API
     * @throws APINotReachableException       if the API is not reachable after retries
     * @throws NotEnoughAPIInstancesException if there are not enough API instances available
     */
    public static HttpResponse run(QueryRef queryRef) throws APINotReachableException, NotEnoughAPIInstancesException {
        int retryCount = 0;
        while (retryCount < maxRetryCount) {
            QueryCall apiCall = new QueryCall(queryRef);
            apiCall.run();
            while (!apiCall.calls.isEmpty() && apiCall.resp == null) {
                try {
                    Thread.sleep(200);
                } catch (InterruptedException ex) {
                    Thread.currentThread().interrupt();
                }
            }
            if (apiCall.resp != null) {
                return apiCall.resp;
            }
            retryCount = retryCount + 1;
        }
        throw new APINotReachableException("Giving up contacting API: " + queryRef.getQueryId());
    }

    /**
     * System property naming a whitespace-separated list of query API instance URLs.
     * When set, this overrides discovery via the nanopub setting (env var
     * {@code NANOPUB_QUERY_INSTANCES} also accepted).
     */
    public static final String QUERY_INSTANCES_PROPERTY = "nanopub.query.instances";

    /**
     * Environment variable equivalent of {@link #QUERY_INSTANCES_PROPERTY}.
     */
    public static final String QUERY_INSTANCES_ENV = "NANOPUB_QUERY_INSTANCES";

    private static List<String> checkedApiInstances;

    /**
     * Returns the list of available query API instances that are currently accessible.
     * <p>
     * Sources, in order of priority:
     * <ol>
     *   <li>{@code nanopub.query.instances} system property / {@code NANOPUB_QUERY_INSTANCES} env var
     *       (whitespace-separated URLs).</li>
     *   <li>The active {@link org.nanopub.extra.setting.NanopubSetting}'s service intro collection,
     *       filtered to services of type {@link NPS#NANOPUB_QUERY_1_1}.</li>
     * </ol>
     * Each candidate is liveness-checked via an HTTP GET to its root URL.
     *
     * @return a list of accessible query API instances
     */
    public static List<String> getApiInstances() throws NotEnoughAPIInstancesException {
        if (checkedApiInstances != null) return checkedApiInstances;
        List<String> candidates = resolveCandidateInstances();
        if (candidates.isEmpty()) {
            throw new NotEnoughAPIInstancesException("No query API instances configured or discoverable");
        }
        checkedApiInstances = new ArrayList<>();
        for (String a : candidates) {
            try {
                logger.info("Checking API instance: {}", a);
                HttpResponse resp = NanopubUtils.getHttpClient().execute(new HttpGet(a));
                if (!wasSuccessful(resp)) {
                    EntityUtils.consumeQuietly(resp.getEntity());
                    logger.error("FAILURE: Nanopub Query instance isn't accessible: {}", a);
                } else if (!isReadyStatus(resp)) {
                    Header h = resp.getFirstHeader(QUERY_STATUS_HEADER);
                    EntityUtils.consumeQuietly(resp.getEntity());
                    logger.error("FAILURE: Nanopub Query instance not ready (status={}): {}", h.getValue(), a);
                } else {
                    EntityUtils.consumeQuietly(resp.getEntity());
                    logger.info("SUCCESS: Nanopub Query instance is accessible: {}", a);
                    checkedApiInstances.add(a);
                }
            } catch (IOException ex) {
                logger.error("FAILURE: Nanopub Query instance isn't accessible: {}", a);
            }
        }
        logger.info("{} accessible Nanopub Query instances", checkedApiInstances.size());
        if (checkedApiInstances.isEmpty()) {
            checkedApiInstances = null;
            throw new NotEnoughAPIInstancesException("No healthy Nanopub Query instances available");
        }
        if (checkedApiInstances.size() == 1) {
            logger.warn("Only one healthy Nanopub Query instance available; no failover.");
        }
        return checkedApiInstances;
    }

    private static List<String> resolveCandidateInstances() {
        String override = System.getProperty(QUERY_INSTANCES_PROPERTY);
        if (override == null || override.isEmpty()) override = System.getenv(QUERY_INSTANCES_ENV);
        if (override != null && !override.trim().isEmpty()) {
            List<String> list = new ArrayList<>();
            for (String url : override.trim().split("\\s+")) list.add(url);
            logger.info("Using {} query API instance(s) from override", list.size());
            return list;
        }
        List<String> fromSetting = ServiceLookup.getServices(NPS.NANOPUB_QUERY_1_1);
        logger.info("Discovered {} query API instance(s) from setting", fromSetting.size());
        return new ArrayList<>(fromSetting);
    }

    private QueryRef queryRef;
    private List<String> apisToCall = new ArrayList<>();
    private List<Call> calls = new ArrayList<>();

    private HttpResponse resp;

    private QueryCall(QueryRef queryRef) {
        this.queryRef = queryRef;
        logger.info("Invoking API operation {}", queryRef);
    }

    private void run() throws NotEnoughAPIInstancesException {
        List<String> candidates = filterEvicted(getApiInstances());
        if (candidates.isEmpty()) {
            throw new NotEnoughAPIInstancesException(
                    "All Nanopub Query instances are currently evicted (loading/resetting); try again later");
        }
        List<String> apiInstancesToTry = new LinkedList<>(candidates);
        int parallelCallCount = getParallelCallCount();
        while (!apiInstancesToTry.isEmpty() && apisToCall.size() < parallelCallCount) {
            int randomIndex = (int) ((Math.random() * apiInstancesToTry.size()));
            String apiUrl = apiInstancesToTry.get(randomIndex);
            apisToCall.add(apiUrl);
            logger.info("Trying API ({}) {}", apisToCall.size(), apiUrl);
            apiInstancesToTry.remove(randomIndex);
        }
        for (String api : apisToCall) {
            Call call = new Call(api);
            calls.add(call);
            new Thread(call).start();
        }
    }

    private synchronized void finished(Call call, HttpResponse resp, String apiUrl) {
        if (this.resp != null) { // result already in
            EntityUtils.consumeQuietly(resp.getEntity());
            return;
        }
        logger.info("Result in from {}:", apiUrl);
        logger.info("- Request: {}", queryRef);
        logger.info("- Response size: {}", resp.getEntity().getContentLength());
        this.resp = resp;

        for (Call c : calls) {
            if (c != call) c.abort();
        }
    }

    private static boolean wasSuccessful(HttpResponse resp) {
        if (resp == null || resp.getEntity() == null) return false;
        int c = resp.getStatusLine().getStatusCode();
        if (c < 200 || c >= 300) return false;
        return true;
    }

    private static boolean wasSuccessfulNonempty(HttpResponse resp) {
        if (!wasSuccessful(resp)) return false;
        // TODO Make sure we always return proper error codes, and then this shouldn't be necessary:
        if (resp.getHeaders("Content-Length").length > 0 && resp.getEntity().getContentLength() < 0) return false;
        return true;
    }


    private class Call implements Runnable {

        private String apiUrl;
        private HttpGet get;

        public Call(String apiUrl) {
            this.apiUrl = apiUrl;
        }

        public void run() {
            get = new HttpGet(apiUrl + "api/" + queryRef.getAsUrlString());
            get.setHeader("Accept", "text/csv, text/turtle;q=0.9, application/ld+json;q=0.8");
            HttpResponse resp = null;
            try {
                resp = NanopubUtils.getHttpClient().execute(get);
                if (!wasSuccessfulNonempty(resp)) {
                    throw new IOException(resp.getStatusLine().toString());
                }
                if (!isReadyStatus(resp)) {
                    Header h = resp.getFirstHeader(QUERY_STATUS_HEADER);
                    String status = h == null ? "missing" : h.getValue();
                    evict(apiUrl, "status " + status);
                    EntityUtils.consumeQuietly(resp.getEntity());
                } else {
                    finished(this, resp, apiUrl);
                }
            } catch (Exception ex) {
                if (resp != null) EntityUtils.consumeQuietly(resp.getEntity());
                logger.error("Request to {} was not successful: {}", apiUrl, ex.getMessage());
            }
            calls.remove(this);
        }

        private void abort() {
            if (get == null) return;
            if (get.isAborted()) return;
            get.abort();
        }

    }

}

1	package org.nanopub.extra.services;
2
3	import org.apache.http.Header;
4	import org.apache.http.HttpResponse;
5	import org.apache.http.client.methods.HttpGet;
6	import org.apache.http.util.EntityUtils;
7	import org.nanopub.NanopubUtils;
8	import org.nanopub.vocabulary.NPS;
9	import org.slf4j.Logger;
10	import org.slf4j.LoggerFactory;
11
12	import java.io.IOException;
13	import java.util.ArrayList;
14	import java.util.Date;
15	import java.util.LinkedList;
16	import java.util.List;
17	import java.util.Locale;
18	import java.util.concurrent.ConcurrentHashMap;
19	import java.util.concurrent.ConcurrentMap;
20
21	/**
22	* Second-generation query API call.
23	*/
24	public class QueryCall {
25
26	private static final int DEFAULT_PARALLEL_CALL_COUNT = 2;
27
28	/**
29	* System property setting how many query API instances to call in parallel.
30	* Must be {@code >= 1}; defaults to {@value #DEFAULT_PARALLEL_CALL_COUNT}.
31	* Env var {@code NANOPUB_QUERY_PARALLEL_CALL_COUNT} also accepted.
32	*/
33	public static final String PARALLEL_CALL_COUNT_PROPERTY = "nanopub.query.parallel-call-count";
34
35	/**
36	* Environment variable equivalent of {@link #PARALLEL_CALL_COUNT_PROPERTY}.
37	*/
38	public static final String PARALLEL_CALL_COUNT_ENV = "NANOPUB_QUERY_PARALLEL_CALL_COUNT";
39
40	private static int maxRetryCount = 3;	6✔
41	private static final Logger logger = LoggerFactory.getLogger(QueryCall.class);	9✔
42
43	/**
44	* Returns the number of query API instances to call in parallel, resolved
45	* (in order) from {@link #PARALLEL_CALL_COUNT_PROPERTY},
46	* {@link #PARALLEL_CALL_COUNT_ENV}, or the default of
47	* {@value #DEFAULT_PARALLEL_CALL_COUNT}. Invalid values are ignored.
48	*
49	* @return the parallel call count (always {@code >= 1})
50	*/
51	public static int getParallelCallCount() {
52	String value = System.getProperty(PARALLEL_CALL_COUNT_PROPERTY);	9✔
53	if (value == null \|\| value.isEmpty()) value = System.getenv(PARALLEL_CALL_COUNT_ENV);	24!
54	if (value != null && !value.trim().isEmpty()) {	18!
55	try {
56	int n = Integer.parseInt(value.trim());	12✔
57	if (n >= 1) return n;	15✔
58	logger.warn("Ignoring {}={}: must be >= 1", PARALLEL_CALL_COUNT_PROPERTY, value);	15✔
59	} catch (NumberFormatException ex) {	3✔
60	logger.warn("Ignoring {}={}: not an integer", PARALLEL_CALL_COUNT_PROPERTY, value);	15✔
61	}	3✔
62	}
63	return DEFAULT_PARALLEL_CALL_COUNT;	6✔
64	}
65
66	/**
67	* HTTP response header carrying the query instance's sync state.
68	* See nanopub-query's {@code StatusController}.
69	*/
70	public static final String QUERY_STATUS_HEADER = "Nanopub-Query-Status";
71
72	/**
73	* System property setting the cool-down (in seconds) before a query instance
74	* evicted for non-ready status is re-considered. Default
75	* {@value #DEFAULT_EVICTION_COOLDOWN_SECONDS}. Env var
76	* {@code NANOPUB_QUERY_EVICTION_COOLDOWN_SECONDS} also accepted.
77	*/
78	public static final String EVICTION_COOLDOWN_PROPERTY = "nanopub.query.eviction-cooldown-seconds";
79
80	/**
81	* Environment variable equivalent of {@link #EVICTION_COOLDOWN_PROPERTY}.
82	*/
83	public static final String EVICTION_COOLDOWN_ENV = "NANOPUB_QUERY_EVICTION_COOLDOWN_SECONDS";
84
85	private static final int DEFAULT_EVICTION_COOLDOWN_SECONDS = 300;
86
87	private static final ConcurrentMap<String, Long> evictedUntil = new ConcurrentHashMap<>();	15✔
88
89	/**
90	* Returns the eviction cool-down in milliseconds, resolved from
91	* {@link #EVICTION_COOLDOWN_PROPERTY}, {@link #EVICTION_COOLDOWN_ENV},
92	* or the default of {@value #DEFAULT_EVICTION_COOLDOWN_SECONDS} seconds.
93	*/
94	public static long getEvictionCooldownMillis() {
95	String value = System.getProperty(EVICTION_COOLDOWN_PROPERTY);	9✔
96	if (value == null \|\| value.isEmpty()) value = System.getenv(EVICTION_COOLDOWN_ENV);	24!
97	if (value != null && !value.trim().isEmpty()) {	18!
98	try {
99	long n = Long.parseLong(value.trim());	12✔
100	if (n >= 0) return n * 1000L;	24✔
101	logger.warn("Ignoring {}={}: must be >= 0", EVICTION_COOLDOWN_PROPERTY, value);	15✔
102	} catch (NumberFormatException ex) {	3✔
103	logger.warn("Ignoring {}={}: not a number", EVICTION_COOLDOWN_PROPERTY, value);	15✔
104	}	3✔
105	}
106	return DEFAULT_EVICTION_COOLDOWN_SECONDS * 1000L;	6✔
107	}
108
109	/**
110	* Returns true if the response's {@link #QUERY_STATUS_HEADER} signals a
111	* fully-synced state ({@code READY} or {@code LOADING_UPDATES}). Missing
112	* header is treated as ready for backwards compatibility with older
113	* query instances.
114	*/
115	static boolean isReadyStatus(HttpResponse resp) {
116	Header h = resp.getFirstHeader(QUERY_STATUS_HEADER);	12✔
117	if (h == null) return true;	12✔
118	String v = h.getValue();	9✔
119	if (v == null \|\| v.isEmpty()) return true;	15!
120	String upper = v.toUpperCase(Locale.ROOT);	12✔
121	return upper.equals("READY") \|\| upper.equals("LOADING_UPDATES");	36✔
122	}
123
124	private static void evict(String apiUrl, String reason) {
125	long until = System.currentTimeMillis() + getEvictionCooldownMillis();	×
126	evictedUntil.put(apiUrl, until);	×
127	logger.warn("Evicting Nanopub Query instance {} until {} ({})", apiUrl, new Date(until), reason);	×
128	}	×
129
130	private static List<String> filterEvicted(List<String> instances) {
131	long now = System.currentTimeMillis();	6✔
132	List<String> result = new ArrayList<>(instances.size());	18✔
133	for (String url : instances) {	30✔
134	Long until = evictedUntil.get(url);	15✔
135	if (until == null \|\| until <= now) result.add(url);	18!
136	}	3✔
137	return result;	6✔
138	}
139
140	/**
141	* Run a query call with the given query ID and parameters.
142	*
143	* @param queryRef the reference to the query to run
144	* @return the HTTP response from the query API
145	* @throws APINotReachableException if the API is not reachable after retries
146	* @throws NotEnoughAPIInstancesException if there are not enough API instances available
147	*/
148	public static HttpResponse run(QueryRef queryRef) throws APINotReachableException, NotEnoughAPIInstancesException {
149	int retryCount = 0;	6✔
150	while (retryCount < maxRetryCount) {	9!
151	QueryCall apiCall = new QueryCall(queryRef);	15✔
152	apiCall.run();	6✔
153	while (!apiCall.calls.isEmpty() && apiCall.resp == null) {	21!
154	try {
155	Thread.sleep(200);	6✔
156	} catch (InterruptedException ex) {	×
157	Thread.currentThread().interrupt();	×
158	}	3✔
159	}
160	if (apiCall.resp != null) {	9!
161	return apiCall.resp;	9✔
162	}
163	retryCount = retryCount + 1;	×
164	}	×
165	throw new APINotReachableException("Giving up contacting API: " + queryRef.getQueryId());	×
166	}
167
168	/**
169	* System property naming a whitespace-separated list of query API instance URLs.
170	* When set, this overrides discovery via the nanopub setting (env var
171	* {@code NANOPUB_QUERY_INSTANCES} also accepted).
172	*/
173	public static final String QUERY_INSTANCES_PROPERTY = "nanopub.query.instances";
174
175	/**
176	* Environment variable equivalent of {@link #QUERY_INSTANCES_PROPERTY}.
177	*/
178	public static final String QUERY_INSTANCES_ENV = "NANOPUB_QUERY_INSTANCES";
179
180	private static List<String> checkedApiInstances;
181
182	/**
183	* Returns the list of available query API instances that are currently accessible.
184	* <p>
185	* Sources, in order of priority:
186	* <ol>
187	* <li>{@code nanopub.query.instances} system property / {@code NANOPUB_QUERY_INSTANCES} env var
188	* (whitespace-separated URLs).</li>
189	* <li>The active {@link org.nanopub.extra.setting.NanopubSetting}'s service intro collection,
190	* filtered to services of type {@link NPS#NANOPUB_QUERY_1_1}.</li>
191	* </ol>
192	* Each candidate is liveness-checked via an HTTP GET to its root URL.
193	*
194	* @return a list of accessible query API instances
195	*/
196	public static List<String> getApiInstances() throws NotEnoughAPIInstancesException {
197	if (checkedApiInstances != null) return checkedApiInstances;	12✔
198	List<String> candidates = resolveCandidateInstances();	6✔
199	if (candidates.isEmpty()) {	9!
200	throw new NotEnoughAPIInstancesException("No query API instances configured or discoverable");	×
201	}
202	checkedApiInstances = new ArrayList<>();	12✔
203	for (String a : candidates) {	30✔
204	try {
205	logger.info("Checking API instance: {}", a);	12✔
206	HttpResponse resp = NanopubUtils.getHttpClient().execute(new HttpGet(a));	21✔
207	if (!wasSuccessful(resp)) {	9✔
208	EntityUtils.consumeQuietly(resp.getEntity());	9✔
209	logger.error("FAILURE: Nanopub Query instance isn't accessible: {}", a);	15✔
210	} else if (!isReadyStatus(resp)) {	9✔
211	Header h = resp.getFirstHeader(QUERY_STATUS_HEADER);	12✔
212	EntityUtils.consumeQuietly(resp.getEntity());	9✔
213	logger.error("FAILURE: Nanopub Query instance not ready (status={}): {}", h.getValue(), a);	18✔
214	} else {	3✔
215	EntityUtils.consumeQuietly(resp.getEntity());	9✔
216	logger.info("SUCCESS: Nanopub Query instance is accessible: {}", a);	12✔
217	checkedApiInstances.add(a);	12✔
218	}
219	} catch (IOException ex) {	×
220	logger.error("FAILURE: Nanopub Query instance isn't accessible: {}", a);	×
221	}	3✔
222	}	3✔
223	logger.info("{} accessible Nanopub Query instances", checkedApiInstances.size());	18✔
224	if (checkedApiInstances.isEmpty()) {	9✔
225	checkedApiInstances = null;	6✔
226	throw new NotEnoughAPIInstancesException("No healthy Nanopub Query instances available");	15✔
227	}
228	if (checkedApiInstances.size() == 1) {	12✔
229	logger.warn("Only one healthy Nanopub Query instance available; no failover.");	9✔
230	}
231	return checkedApiInstances;	6✔
232	}
233
234	private static List<String> resolveCandidateInstances() {
235	String override = System.getProperty(QUERY_INSTANCES_PROPERTY);	9✔
236	if (override == null \|\| override.isEmpty()) override = System.getenv(QUERY_INSTANCES_ENV);	24!
237	if (override != null && !override.trim().isEmpty()) {	18!
238	List<String> list = new ArrayList<>();	12✔
239	for (String url : override.trim().split("\\s+")) list.add(url);	69✔
240	logger.info("Using {} query API instance(s) from override", list.size());	18✔
241	return list;	6✔
242	}
243	List<String> fromSetting = ServiceLookup.getServices(NPS.NANOPUB_QUERY_1_1);	9✔
244	logger.info("Discovered {} query API instance(s) from setting", fromSetting.size());	18✔
245	return new ArrayList<>(fromSetting);	15✔
246	}
247
248	private QueryRef queryRef;
249	private List<String> apisToCall = new ArrayList<>();	15✔
250	private List<Call> calls = new ArrayList<>();	15✔
251
252	private HttpResponse resp;
253
254	private QueryCall(QueryRef queryRef) {	6✔
255	this.queryRef = queryRef;	9✔
256	logger.info("Invoking API operation {}", queryRef);	12✔
257	}	3✔
258
259	private void run() throws NotEnoughAPIInstancesException {
260	List<String> candidates = filterEvicted(getApiInstances());	9✔
261	if (candidates.isEmpty()) {	9!
262	throw new NotEnoughAPIInstancesException(	×
263	"All Nanopub Query instances are currently evicted (loading/resetting); try again later");
264	}
265	List<String> apiInstancesToTry = new LinkedList<>(candidates);	15✔
266	int parallelCallCount = getParallelCallCount();	6✔
267	while (!apiInstancesToTry.isEmpty() && apisToCall.size() < parallelCallCount) {	24!
268	int randomIndex = (int) ((Math.random() * apiInstancesToTry.size()));	21✔
269	String apiUrl = apiInstancesToTry.get(randomIndex);	15✔
270	apisToCall.add(apiUrl);	15✔
271	logger.info("Trying API ({}) {}", apisToCall.size(), apiUrl);	24✔
272	apiInstancesToTry.remove(randomIndex);	12✔
273	}	3✔
274	for (String api : apisToCall) {	33✔
275	Call call = new Call(api);	18✔
276	calls.add(call);	15✔
277	new Thread(call).start();	15✔
278	}	3✔
279	}	3✔
280
281	private synchronized void finished(Call call, HttpResponse resp, String apiUrl) {
282	if (this.resp != null) { // result already in	9!
283	EntityUtils.consumeQuietly(resp.getEntity());	×
284	return;	×
285	}
286	logger.info("Result in from {}:", apiUrl);	12✔
287	logger.info("- Request: {}", queryRef);	15✔
288	logger.info("- Response size: {}", resp.getEntity().getContentLength());	21✔
289	this.resp = resp;	9✔
290
291	for (Call c : calls) {	33✔
292	if (c != call) c.abort();	15✔
293	}	3✔
294	}	3✔
295
296	private static boolean wasSuccessful(HttpResponse resp) {
297	if (resp == null \|\| resp.getEntity() == null) return false;	15!
298	int c = resp.getStatusLine().getStatusCode();	12✔
299	if (c < 200 \|\| c >= 300) return false;	24!
300	return true;	6✔
301	}
302
303	private static boolean wasSuccessfulNonempty(HttpResponse resp) {
304	if (!wasSuccessful(resp)) return false;	9!
305	// TODO Make sure we always return proper error codes, and then this shouldn't be necessary:
306	if (resp.getHeaders("Content-Length").length > 0 && resp.getEntity().getContentLength() < 0) return false;	33!
307	return true;	6✔
308	}
309
310
311	private class Call implements Runnable {
312
313	private String apiUrl;
314	private HttpGet get;
315
316	public Call(String apiUrl) {	15✔
317	this.apiUrl = apiUrl;	9✔
318	}	3✔
319
320	public void run() {
321	get = new HttpGet(apiUrl + "api/" + queryRef.getAsUrlString());	36✔
322	get.setHeader("Accept", "text/csv, text/turtle;q=0.9, application/ld+json;q=0.8");	15✔
323	HttpResponse resp = null;	6✔
324	try {
325	resp = NanopubUtils.getHttpClient().execute(get);	15✔
326	if (!wasSuccessfulNonempty(resp)) {	9!
327	throw new IOException(resp.getStatusLine().toString());	×
328	}
329	if (!isReadyStatus(resp)) {	9!
330	Header h = resp.getFirstHeader(QUERY_STATUS_HEADER);	×
331	String status = h == null ? "missing" : h.getValue();	×
332	evict(apiUrl, "status " + status);	×
333	EntityUtils.consumeQuietly(resp.getEntity());	×
334	} else {	×
335	finished(this, resp, apiUrl);	21✔
336	}
337	} catch (Exception ex) {	3✔
338	if (resp != null) EntityUtils.consumeQuietly(resp.getEntity());	6!
339	logger.error("Request to {} was not successful: {}", apiUrl, ex.getMessage());	21✔
340	}	3✔
341	calls.remove(this);	18✔
342	}	3✔
343
344	private void abort() {
345	if (get == null) return;	9!
346	if (get.isAborted()) return;	12!
347	get.abort();	9✔
348	}	3✔
349
350	}
351
352	}

Nanopublication / nanopub-java / 25662474597

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