Add routes for stashing and reading a timed collection (#103)

Signed-off-by: markcor11 <[email protected]>

AUTHORS.md

@@ -8,4 +8,4 @@ Authors ordered by first contribution
  - Howard Hellyer (https://github.com/hhellyer)
  - Richard Chamberlain (https://github.com/rnchamberlain)
  - James Wallis (https://github.com/jamesemwallis)
-
+ - Mark Cornaia (https://github.com/markcor11)

rest/pom.xml

@@ -58,6 +58,12 @@
     	<version>2.0</version>
     	<scope>provided</scope>
     </dependency>
+    <dependency>
+      <groupId>javax.json</groupId>
+      <artifactId>javax.json-api</artifactId>
+      <version>1.1</version>
+      <scope>provided</scope>
+    </dependency>
   </dependencies>
 
   <build>

rest/src/main/java/com/ibm/javametrics/rest/api/MetricsEndpoint.java

@@ -30,15 +30,25 @@
 import javax.ws.rs.core.Response.Status;
 import javax.ws.rs.core.UriBuilder;
 import javax.ws.rs.core.UriInfo;
-
+import javax.json.Json;
+import javax.json.JsonObjectBuilder;
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.util.Timer;
+import java.util.TimerTask;
 import com.ibm.javametrics.analysis.MetricsData;
 import com.ibm.javametrics.analysis.MetricsProcessor;
 
 @Path("collections")
 public class MetricsEndpoint {
 
     MetricsProcessor mp = MetricsProcessor.getInstance();
+    final String METRICSFILE_PREFIX = getTempDir() + "/javametrics-collection";
 
+    // Get a list of running metric collections
     @GET
     @Produces(MediaType.APPLICATION_JSON)
     public Response getContexts(@Context UriInfo uriInfo) {
@@ -62,6 +72,7 @@ public Response getContexts(@Context UriInfo uriInfo) {
         return Response.ok(sb.toString()).build();
     }
 
+    // Begin collecting a new set of metrics
     @POST
     @Produces(MediaType.APPLICATION_JSON)
     public Response newContext(@Context UriInfo uriInfo) {
@@ -75,6 +86,7 @@ public Response newContext(@Context UriInfo uriInfo) {
         return Response.status(Status.CREATED).header("Location", uri).entity("{\"uri\":\"" + uri + "\"}").build();
     }
 
+    // Return the metrics collected so far by ID {metricsId}
     @Path("/{metricsId}")
     @GET
     @Produces(MediaType.APPLICATION_JSON)
@@ -87,6 +99,7 @@ public Response getMetrics(@PathParam("metricsId") int id) {
         return Response.ok(metrics.toJson(id)).build();
     }
 
+    // Reset the metrics collected by {metricsId}
     @Path("/{metricsId}")
     @PUT
     @Produces(MediaType.APPLICATION_JSON)
@@ -99,6 +112,7 @@ public Response resetContext(@PathParam("metricsId") int id) {
         return Response.noContent().build();
     }
 
+    // Delete the collection by {metricsId}
     @Path("/{metricsId}")
     @DELETE
     public Response deleteContext(@PathParam("metricsId") int id) {
@@ -110,4 +124,99 @@ public Response deleteContext(@PathParam("metricsId") int id) {
         return Response.noContent().build();
     }
 
+    // Start collecting a timed run of metrics for {seconds}.
+    // Returns the collection path that includes an ID which can be used to retrieve the summary
+    @Path("/{seconds}")
+    @POST
+    @Produces(MediaType.APPLICATION_JSON)
+    public Response newTimedContext(@Context UriInfo uriInfo, @PathParam("seconds") int seconds) {
+        if (mp.getContextIds().length > 9) {
+            return Response.status(Status.BAD_REQUEST).build();
+        }
+
+        int contextId = mp.addContext();
+        String metricsFilePath =  METRICSFILE_PREFIX + String.valueOf(contextId);
+        URI uri = getCollectionIDFromURIInfo(uriInfo, contextId);
+
+        // Start timing the collection recording
+        Timer timer = new Timer();
+        System.out.println("JavaMetrics: Started metrics collection #"+contextId);
+        TimerTask collectionTimerTask = createCollectionTimer(timer, metricsFilePath, contextId);
+        timer.schedule(collectionTimerTask, seconds * 1000);
+
+        return Response.status(Status.CREATED).header("Location", uri).entity("{\"uri\":\"" + uri + "\"}").build();
+    }
+
+    private URI getCollectionIDFromURIInfo(UriInfo uriInfo, int contextId) {
+        // remove parameters from url
+        String urlPath = uriInfo.getPath();
+        UriBuilder builder = UriBuilder.fromPath(urlPath.substring(0,urlPath.indexOf("/")));
+        builder.path(Integer.toString(contextId));
+        return builder.build();
+    }
+
+    // Fetch the recorded stashed metrics and remove the temp file if it exists
+    @Path("/{metricsId}/stashed")
+    @GET
+    @Produces(MediaType.APPLICATION_JSON)
+    public Response getStashedMetrics(@PathParam("metricsId") int id) {
+        try {
+            if (!mp.removeContext(id)) {
+                return Response.status(Status.NOT_FOUND).build();
+            }
+            String metricsFilePath = METRICSFILE_PREFIX+String.valueOf(id);
+            File tempFile = new File(metricsFilePath);
+            if (!tempFile.exists() || tempFile.isDirectory()) {
+                return Response.status(Status.NOT_FOUND).build();
+            }
+            String data = new String(Files.readAllBytes(Paths.get(metricsFilePath)));
+            tempFile.delete();
+            return Response.ok(data).build();
+		} catch (Exception e) {
+            return Response.status(Status.INTERNAL_SERVER_ERROR).build();
+        }
+    }
+
+     // Return the metrics collected so far by ID {metricsId}
+     @Path("/features")
+     @GET
+     @Produces(MediaType.APPLICATION_JSON)
+     public Response getFeatures(@Context UriInfo uriInfo) {
+        JsonObjectBuilder featureList = Json.createObjectBuilder();
+        featureList.add("timedMetrics",true);
+        return Response.ok(featureList.build()).build();
+     }
+
+    private String getTempDir() {
+        return System.getProperty("java.io.tmpdir");
+    }
+
+
+    private TimerTask createCollectionTimer(Timer timer, String metricsFilePath, int contextId) {
+        return new TimerTask() {
+            public void run() {
+                Thread timerThread = collectionTimerThread(timer,  metricsFilePath,  contextId);
+                timerThread.start();
+            }
+        };
+    }
+
+    private Thread collectionTimerThread(Timer timer, String metricsFilePath, int contextId) {
+        return new Thread(new Runnable() {
+            public void run() {
+                try (FileWriter tempFile = new FileWriter(metricsFilePath)) {
+                    MetricsData metrics = mp.getMetricsData(contextId);
+                    if (metrics == null) {
+                        System.out.println("JavaMetrics: Unable to locate the running collection");
+                    } else {
+                        tempFile.write(metrics.toJson(contextId));
+                        System.out.println("JavaMetrics: Stashed collection # "+contextId);
+                    }
+                } catch (IOException e) {
+                    e.printStackTrace();
+                }
+                timer.cancel();
+            }
+        });
+    }
 }