import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
+import java.net.ProtocolException;
import java.net.URL;
import java.util.HashMap;
import java.util.List;
private static final int CONNECT_TIMEOUT_MS = 10 * 1000; // 10 seconds
+ private static final int MAX_RETRIES = 3;
+
+ private static final int HTTP_OK = 200;
+
+ private static final int HTTP_OVERLOAD = 429;
+
/*
* update these constants when Jalview has been checked / updated for
* changes to Ensembl REST API (ref JAL-2105)
* @see http://rest.ensembl.org/documentation/info/ping
* @return
*/
- private boolean checkEnsembl()
+ boolean checkEnsembl()
{
BufferedReader br = null;
try
* if ping takes more than 2 seconds to respond, treat as if unavailable
*/
br = getHttpResponse(ping, null, 2 * 1000);
+ if (br == null)
+ {
+ return false;
+ }
JSONParser jp = new JSONParser();
JSONObject val = (JSONObject) jp.parse(br);
String pingString = val.get("ping").toString();
}
/**
- * Writes the HTTP request and gets the response as a reader.
+ * Sends the HTTP request and gets the response as a reader
*
* @param url
* @param ids
protected BufferedReader getHttpResponse(URL url, List<String> ids,
int readTimeout) throws IOException
{
- // long now = System.currentTimeMillis();
+ int retriesLeft = MAX_RETRIES;
+ HttpURLConnection connection = null;
+ int responseCode = 0;
+
+ while (retriesLeft > 0)
+ {
+ connection = tryConnection(url, ids, readTimeout);
+ responseCode = connection.getResponseCode();
+ if (responseCode == HTTP_OVERLOAD) // 429
+ {
+ retriesLeft--;
+ checkRetryAfter(connection);
+ }
+ else
+ {
+ retriesLeft = 0;
+ }
+ }
+ if (responseCode != HTTP_OK) // 200
+ {
+ /*
+ * note: a GET request for an invalid id returns an error code e.g. 415
+ * but POST request returns 200 and an empty Fasta response
+ */
+ System.err.println("Response code " + responseCode + " for " + url);
+ return null;
+ }
+
+ InputStream response = connection.getInputStream();
+
+ // System.out.println(getClass().getName() + " took "
+ // + (System.currentTimeMillis() - now) + "ms to fetch");
+
+ BufferedReader reader = null;
+ reader = new BufferedReader(new InputStreamReader(response, "UTF-8"));
+ return reader;
+ }
+
+ /**
+ * @param url
+ * @param ids
+ * @param readTimeout
+ * @return
+ * @throws IOException
+ * @throws ProtocolException
+ */
+ protected HttpURLConnection tryConnection(URL url, List<String> ids,
+ int readTimeout) throws IOException, ProtocolException
+ {
+ // System.out.println(System.currentTimeMillis() + " " + url);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
/*
{
writePostBody(connection, ids);
}
-
- int responseCode = connection.getResponseCode();
-
- if (responseCode != 200)
- {
- /*
- * note: a GET request for an invalid id returns an error code e.g. 415
- * but POST request returns 200 and an empty Fasta response
- */
- System.err.println("Response code " + responseCode + " for " + url);
- return null;
- }
- // get content
- InputStream response = connection.getInputStream();
-
- // System.out.println(getClass().getName() + " took "
- // + (System.currentTimeMillis() - now) + "ms to fetch");
-
- checkRateLimits(connection);
-
- BufferedReader reader = null;
- reader = new BufferedReader(new InputStreamReader(response, "UTF-8"));
- return reader;
+ return connection;
}
/**
- * Inspect response headers for any sign of server overload and respect any
- * 'retry-after' directive
+ * Inspects response headers for a 'retry-after' directive, and waits for the
+ * directed period (if less than 10 seconds)
*
* @see https://github.com/Ensembl/ensembl-rest/wiki/Rate-Limits
* @param connection
*/
- void checkRateLimits(HttpURLConnection connection)
+ void checkRetryAfter(HttpURLConnection connection)
{
- // number of requests allowed per time interval:
- String limit = connection.getHeaderField("X-RateLimit-Limit");
- // length of quota time interval in seconds:
- // String period = connection.getHeaderField("X-RateLimit-Period");
- // seconds remaining until usage quota is reset:
- String reset = connection.getHeaderField("X-RateLimit-Reset");
- // number of requests remaining from quota for current period:
- String remaining = connection.getHeaderField("X-RateLimit-Remaining");
- // number of seconds to wait before retrying (if remaining == 0)
String retryDelay = connection.getHeaderField("Retry-After");
// to test:
// retryDelay = "5";
- EnsemblInfo info = domainData.get(getDomain());
if (retryDelay != null)
{
- System.err.println("Ensembl REST service rate limit exceeded, wait "
- + retryDelay + " seconds before retrying");
try
{
- info.retryAfter = System.currentTimeMillis()
- + (1000 * Integer.valueOf(retryDelay));
- } catch (NumberFormatException e)
+ int retrySecs = Integer.valueOf(retryDelay);
+ if (retrySecs > 0 && retrySecs < 10)
+ {
+ System.err
+ .println("Ensembl REST service rate limit exceeded, waiting "
+ + retryDelay + " seconds before retrying");
+ Thread.sleep(1000 * retrySecs);
+ }
+ } catch (NumberFormatException | InterruptedException e)
{
- System.err
- .println("Unexpected value for Retry-After: " + retryDelay);
+ System.err.println("Error handling Retry-After: " + e.getMessage());
}
}
- else
- {
- info.retryAfter = 0;
- // debug:
- // System.out.println(String.format(
- // "%s Ensembl requests remaining of %s (reset in %ss)",
- // remaining, limit, reset));
- }
}
/**
long now = System.currentTimeMillis();
/*
- * check if we are waiting for 'Retry-After' to expire
- */
- if (info.retryAfter > now)
- {
- System.err.println("Still " + (1 + (info.retryAfter - now) / 1000)
- + " secs to wait before retrying Ensembl");
- return false;
- }
- else
- {
- info.retryAfter = 0;
- }
-
- /*
* recheck if Ensembl is up if it was down, or the recheck period has elapsed
*/
boolean retestAvailability = (now
{
JSONParser jp = new JSONParser();
URL url = null;
+ BufferedReader br = null;
+
try
{
url = new URL(
getDomain() + "/info/data?content-type=application/json");
- BufferedReader br = getHttpResponse(url, null);
- JSONObject val = (JSONObject) jp.parse(br);
- JSONArray versions = (JSONArray) val.get("releases");
- domainData.get(getDomain()).dataVersion = versions.get(0).toString();
+ br = getHttpResponse(url, null);
+ if (br != null)
+ {
+ JSONObject val = (JSONObject) jp.parse(br);
+ JSONArray versions = (JSONArray) val.get("releases");
+ domainData.get(getDomain()).dataVersion = versions.get(0)
+ .toString();
+ }
} catch (Throwable t)
{
System.err.println(
"Error checking Ensembl data version: " + t.getMessage());
+ } finally
+ {
+ if (br != null)
+ {
+ try
+ {
+ br.close();
+ } catch (IOException e)
+ {
+ // ignore
+ }
+ }
}
}
git://source.jalview.org / jalview.git / commitdiff