UX tweaks, better output request behaviour

src/main/java/JobServ/JobServClient.java

@@ -54,8 +54,8 @@ public class JobServClient {
         try {
             return Integer.parseInt(this.programArgs[index]);
 
-        } catch (InputMismatchException e) {
+        } catch (NumberFormatException e) {
-            System.out.println(this.programArgs[index] + " is not a valid int, much less a valid pid");
+            System.out.println(this.programArgs[index] + " is not a valid integer");
             return -1;
         }
 
@@ -69,9 +69,9 @@ public class JobServClient {
         System.out.println("... new (command)\n"+
                            "Starts a new process on the server\n"+
                            "example: ./client key.pem cert.crt ca.crt localhost 8448 new echo hello world!\n\n"+
-                           "... output (pid)\n"+
+                           "... output (pid) (lines)\n"+
-                           "Garners output from process on server\n"+
+                           "Garners (lines) lines of output from process (pid) on server\n"+
-                           "example: ./client key.pem cert.crt ca.crt localhost 8448 output 0\n\n"+
+                           "example: ./client key.pem cert.crt ca.crt localhost 8448 output 0 5\n\n"+
                            "... status (pid)\n"+
                            "Returns whether process on server is running"+
                            "example: ./client key.pem cert.crt ca.crt localhost 8448 status 0\n\n"+
@@ -88,11 +88,6 @@ public class JobServClient {
      * makes a new process
      */
     public void makeNewProcess() {
-        if (this.programArgs.length < 6) {
-            System.out.println("Improper formatting, try client --help");
-            return;
-        }
-
         String command = "";
         for (int token = 6; token < this.programArgs.length; token++) {
             command += " " + this.programArgs[token];
@@ -121,12 +116,18 @@ public class JobServClient {
      * gets output from a process
      */
     public void getOutput() {
+        if (this.programArgs.length < 8) {
+            System.out.println("Improper formatting, need a lines and a pid argument.");
+            return;
+        }
+
         int candidatePid = this.getPidArg(6);
+        int lines = this.getPidArg(7);
         if (candidatePid < 0) {
             return;
         }
 
-        String processOutput = this.api.getProcessOutput(candidatePid);
+        String processOutput = this.api.getProcessOutput(candidatePid, lines);
         System.out.println(processOutput);
     }
 

src/main/java/JobServ/JobServClientAPIConnector.java

@@ -63,11 +63,12 @@ class JobServClientAPIConnector {
      * sends the server a request for output from the process identified by 'pid'
      * returns process output as string
      */
-    public String getProcessOutput(int pid) {
+    public String getProcessOutput(int pid, int lines) {
         logger.info("[+] requesting output");
 
-        PIDMessage request = PIDMessage.newBuilder()
+        OutputRequestMessage request = OutputRequestMessage.newBuilder()
             .setPid(pid)
+            .setLines(lines)
             .build();
         OutputMessage response;
 

src/main/java/JobServ/ProcessController.java

@@ -8,10 +8,11 @@
 
 package JobServ;
 
-import java.util.Scanner;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.IOException;
+import java.io.InputStreamReader;
+import java.io.BufferedReader;
 
 /*
  * ProcessController
@@ -28,7 +29,8 @@ class ProcessController {
     // interactive processes (out of scope for initial API)
     private OutputStream output;
     private InputStream input;
-    private Scanner outputScanner;
+    private InputStreamReader inputIntermediateStream;
+    private BufferedReader reader;
 
     private Process process;
 
@@ -46,8 +48,8 @@ class ProcessController {
         this.process = Runtime.getRuntime().exec(command);
         this.output = this.process.getOutputStream();
         this.input = this.process.getInputStream();
-        this.outputScanner = new Scanner(this.input);
+        this.inputIntermediateStream = new InputStreamReader(this.input);
-        this.outputScanner.useDelimiter("\\A");
+        this.reader = new BufferedReader(this.inputIntermediateStream);
     }
 
     /*
@@ -61,9 +63,6 @@ class ProcessController {
     /*
      * getStatus()
      * returns whether or not the process is running
-     * this isnt a very direct way of getting the information
-     * The alternative is to use reflection to get into the private UNIXProcess class
-     * for the PID and to check that against 'ps' or a similar command
      *
      * TODO: (for future release) return thread state
      */
@@ -85,7 +84,7 @@ class ProcessController {
      * returns the exit code of the process
      * 256 if process is still running
      * 257 if process was killed manually and no longer exists
-     * (unix/posix defines an exit code as a uint8, so 256 is fair game)
+     * (unix/posix defines an exit code as a uint8, so 256+ is fair game)
      */
     public int getReturn() {
         if (this.killedManually) {
@@ -103,17 +102,23 @@ class ProcessController {
      * getOutput()
      * gets output from process
      */
-    public String getOutput() {
+    public String getOutput(int lines) {
-        if (this.killedManually) {
+        String output = "";
-            return "";
+        for (int i = 0; i < lines; i++) {
+            String newLine = null;
+            try {
+                newLine = reader.readLine();
+            } catch (IOException e) {
+                newLine = "[-] SERVER: error reading process output: " + e.getMessage();
+            } finally {
+                if (newLine != null) {
+                    output += newLine + "\n";
+                }
             }
 
-        String out = "";
-        while(outputScanner.hasNext()) {
-            out += outputScanner.next();
         }
 
-        return out;
+        return output;
     }
 
     /*
@@ -121,15 +126,20 @@ class ProcessController {
      * Cleans up resources and destroys process
      */
     public void kill() {
+        if (this.killedManually) {
+            System.err.println("[~] Tried to kill already killed process");
+            return;
+        }
+
         try {
             this.input.close();
             this.output.close();
-            this.outputScanner.close();
+            this.inputIntermediateStream.close();
+            this.reader.close();
             this.process.destroy();
-        } catch (IOException e) {
-            // streams already closed
-        }
-
             this.killedManually = true;
+        } catch (IOException e) {
+            System.err.println("[-] Killing process failed: " + e.getMessage());
+        }
     }
 }

src/main/java/JobServ/ProcessManager.java

@@ -140,7 +140,7 @@ class ProcessManager {
      * returns output of process 'pid'
      * or returns description of error
      */
-    public String getProcessOutput(int pid) {
+    public String getProcessOutput(int pid, int lines) {
         try {
             if(!this.getLock(pid)) {
                 return "[-] SERVER: Process not found";
@@ -152,7 +152,7 @@ class ProcessManager {
         }
 
         ProcessController candidate = this.processMap.get(pid);
-        String output = candidate.getOutput();
+        String output = candidate.getOutput(lines);
         this.releaseLock(pid);
         return output;
     }

src/main/java/JobServ/ShellServerService.java

@@ -47,10 +47,11 @@ class ShellServerService extends ShellServerGrpc.ShellServerImplBase {
      * implements api endpoint as defined in jobserv.proto
      */
     @Override
-    public void getOutput(PIDMessage request,
+    public void getOutput(OutputRequestMessage request,
                           StreamObserver<OutputMessage> responder) {
 
-        String output = manager.getProcessOutput(request.getPid());
+        String output = manager.getProcessOutput(request.getPid(),
+                                                 request.getLines());
 
         OutputMessage reply = OutputMessage.newBuilder()
             .setOutput(output)
@@ -67,7 +68,8 @@ class ShellServerService extends ShellServerGrpc.ShellServerImplBase {
     public void newJob(NewJobMessage request,
                        StreamObserver<PIDMessage> responder) {
 
-        int newPid = manager.newProcess(request.getCommand());
+        String command = request.getCommand();
+        int newPid = manager.newProcess(command);
 
         PIDMessage reply = PIDMessage.newBuilder()
             .setPid(newPid)
@@ -101,7 +103,7 @@ class ShellServerService extends ShellServerGrpc.ShellServerImplBase {
     public void killJob(PIDMessage request,
                         StreamObserver<StatusMessage> responder) {
 
-        int status = manager.getProcessStatus(request.getPid());
+        int status = manager.killProcess(request.getPid());
 
         StatusMessage reply = StatusMessage.newBuilder()
             .setProcessStatus(status)

src/main/proto/jobserv.proto

@@ -10,7 +10,7 @@ package JobServ;
 service ShellServer {
         rpc getStatus (PIDMessage) returns (StatusMessage) {}
         rpc getReturn (PIDMessage) returns (ReturnMessage) {}
-        rpc getOutput (PIDMessage) returns (OutputMessage) {}
+        rpc getOutput (OutputRequestMessage) returns (OutputMessage) {}
         rpc killJob   (PIDMessage) returns (StatusMessage) {}
         rpc newJob    (NewJobMessage) returns (PIDMessage) {}
 }
@@ -23,6 +23,11 @@ message ReturnMessage {
         int32 ProcessReturnCode = 1;
 }
 
+message OutputRequestMessage {
+        int32 Pid = 1;
+        int32 Lines = 2;
+}
+
 message OutputMessage {
         string Output = 1;
 }

src/test/java/JobServ/ProcessManagerTest.java

@@ -145,7 +145,7 @@ public class ProcessManagerTest {
             //
         }
 
-        String out = manager.getProcessOutput(pid);
+        String out = manager.getProcessOutput(pid, 2);
         assertEquals("test\n", out); // calls string.equals()
 
         manager.shutdown();
@@ -159,7 +159,7 @@ public class ProcessManagerTest {
      */
     @Test
     public void getUnknownOutputTest() {
-        String out = manager.getProcessOutput(532);
+        String out = manager.getProcessOutput(532, 10);
         assertEquals("[-] SERVER: Process not found", out);
         manager.shutdown();
     }