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Add CPU profiling support to the AdminServlet (fixes dropwizard#927)
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81 changes: 81 additions & 0 deletions
81
metrics-servlets/src/main/java/com/codahale/metrics/servlets/CpuProfileServlet.java
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,81 @@ | ||
| package com.codahale.metrics.servlets; | ||
|
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| import java.io.IOException; | ||
| import java.io.OutputStream; | ||
| import java.util.concurrent.locks.Lock; | ||
| import java.util.concurrent.locks.ReentrantLock; | ||
| import javax.servlet.ServletException; | ||
| import javax.servlet.http.HttpServlet; | ||
| import javax.servlet.http.HttpServletRequest; | ||
| import javax.servlet.http.HttpServletResponse; | ||
| import org.joda.time.Duration; | ||
| import com.papertrail.profiler.CpuProfile; | ||
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|
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| /** | ||
| * An HTTP servlets which outputs a {@link https://github.com/gperftools/gperftools} parseable response. | ||
| */ | ||
| public class CpuProfileServlet extends HttpServlet { | ||
| private static final long serialVersionUID = -668666696530287501L; | ||
| private static final String CONTENT_TYPE = "pprof/raw"; | ||
| private static final String CACHE_CONTROL = "Cache-Control"; | ||
| private static final String NO_CACHE = "must-revalidate,no-cache,no-store"; | ||
| private final Lock lock = new ReentrantLock(); | ||
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| @Override | ||
| protected void doGet(HttpServletRequest req, | ||
| HttpServletResponse resp) throws ServletException, IOException { | ||
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| int duration = 10; | ||
| if (req.getParameter("duration") != null) { | ||
| try { | ||
| duration = Integer.parseInt(req.getParameter("duration")); | ||
| } catch (NumberFormatException e) { | ||
| duration = 10; | ||
| } | ||
| } | ||
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| int frequency = 100; | ||
| if (req.getParameter("frequency") != null) { | ||
| try { | ||
| frequency = Integer.parseInt(req.getParameter("frequency")); | ||
| } catch (NumberFormatException e) { | ||
| frequency = 100; | ||
| } | ||
| } | ||
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| final Thread.State state; | ||
| if ("blocked".equalsIgnoreCase(req.getParameter("state"))) { | ||
| state = Thread.State.BLOCKED; | ||
| } | ||
| else { | ||
| state = Thread.State.RUNNABLE; | ||
| } | ||
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| resp.setStatus(HttpServletResponse.SC_OK); | ||
| resp.setHeader(CACHE_CONTROL, NO_CACHE); | ||
| resp.setContentType(CONTENT_TYPE); | ||
| final OutputStream output = resp.getOutputStream(); | ||
| try { | ||
| doProfile(output, duration, frequency, state); | ||
| } finally { | ||
| output.close(); | ||
| } | ||
| } | ||
|
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| protected void doProfile(OutputStream out, int duration, int frequency, Thread.State state) throws IOException { | ||
| if (lock.tryLock()) { | ||
| try { | ||
| CpuProfile profile = CpuProfile.record(Duration.standardSeconds(duration), | ||
| frequency, state); | ||
| if (profile == null) { | ||
| throw new RuntimeException("could not create CpuProfile"); | ||
| } | ||
| profile.writeGoogleProfile(out); | ||
| return; | ||
| } finally { | ||
| lock.unlock(); | ||
| } | ||
| } | ||
| throw new RuntimeException("Only one profile request may be active at a time"); | ||
| } | ||
| } |
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43 changes: 43 additions & 0 deletions
43
metrics-servlets/src/test/java/com/codahale/metrics/servlets/CpuProfileServletTest.java
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,43 @@ | ||
| package com.codahale.metrics.servlets; | ||
|
|
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| import static org.assertj.core.api.Assertions.assertThat; | ||
| import org.eclipse.jetty.http.HttpHeader; | ||
| import org.eclipse.jetty.servlet.ServletTester; | ||
| import org.junit.Before; | ||
| import org.junit.Test; | ||
|
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| public class CpuProfileServletTest extends AbstractServletTest { | ||
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| @Override | ||
| protected void setUp(ServletTester tester) { | ||
| tester.addServlet(CpuProfileServlet.class, "/pprof"); | ||
| } | ||
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| @Before | ||
| public void setUp() throws Exception { | ||
| request.setMethod("GET"); | ||
| request.setURI("/pprof?duration=1"); | ||
| request.setVersion("HTTP/1.0"); | ||
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| processRequest(); | ||
| } | ||
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| @Test | ||
| public void returns200OK() throws Exception { | ||
| assertThat(response.getStatus()) | ||
| .isEqualTo(200); | ||
| } | ||
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| @Test | ||
| public void returnsPprofRaw() throws Exception { | ||
| assertThat(response.get(HttpHeader.CONTENT_TYPE)) | ||
| .isEqualTo("pprof/raw"); | ||
| } | ||
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| @Test | ||
| public void returnsUncacheable() throws Exception { | ||
| assertThat(response.get(HttpHeader.CACHE_CONTROL)) | ||
| .isEqualTo("must-revalidate,no-cache,no-store"); | ||
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| } | ||
| } |