fix: #35

introduced REST_MAX_WORKER_COUNT

README.md

@@ -26,10 +26,11 @@ in the Context Configuration:
 | REST_WD                       |  The working directory to be set for every request |
 | REST_ADAPTERPGM               |  The adapter, typically RestBCAdapter.bbj |
 | REST_ADAPTERTERM              |  The terminal to set, e.g. IO or Tx |
-| REST_TIMEOUT                  |  The timeout after which idle background workers terminate. Default: 60 seconds. | Timeout after 
+| REST_TIMEOUT                  |  The timeout after which idle background workers terminate. Default: 60 seconds. 
+| REST_SERVLET_TIMEOUT | Timeout after 
 which a timeout is sent as response if the worker did not return in this moment. |
 | REST_KILL_WORKER_AT_TIMEOUT | If set to 1 the worker will be killed when the servlet observes a timeout. If not set or 0, the worker will continue to run, potentially for a long time if the request was bad and leads to long code execution. |
-| REST_WORKER_IDLEOUT | The timeout after which idle background workers terminate. Default: 60 seconds. |
+| REST_MAX_WORKER_COUNT | The maximum number of parallel workers per user |
 | REST_MAX_WORKER_RECYCLECOUNT | The number of rounds a worker is re-used before it ends itself and cleans up |
 | REST_AUTHPGM                  | The authentication program handling custom authentication rules. Default: authenticate.bbj |
 | REST_REQUESTLOG               |  Optional: path to a VKeyed file that will log every request |

RestBCAdapter.bbj

@@ -81,9 +81,9 @@ responseSemaphore! = BBjAPI().getGlobalNamespace().getValue(ses$+"_RESPONSE_SEM"
 done_login:
 
 
-REST_WORKER_IDLEOUT=60
-if servletParams!.containsKey("REST_WORKER_IDLEOUT") then
-    REST_WORKER_IDLEOUT=num(servletParams!.get("REST_WORKER_IDLEOUT").toString(),err=*next)
+REST_TIMEOUT=60
+if servletParams!.containsKey("REST_TIMEOUT") then
+    REST_TIMEOUT=num(servletParams!.get("REST_TIMEOUT").toString(),err=*next)
 endif
 
 
@@ -95,15 +95,15 @@ endif
 
 main_loop:
 
-    CLEAR EXCEPT user$, password$, ses$, requestSemaphore!, responseSemaphore!, ses!, authenticated, REST_WORKER_IDLEOUT, usecount, debug, authpgm$, servletParams!, REST_MAX_WORKER_RECYCLECOUNT
+    CLEAR EXCEPT user$, password$, ses$, requestSemaphore!, responseSemaphore!, ses!, authenticated, REST_TIMEOUT, usecount, debug, authpgm$, servletParams!, REST_MAX_WORKER_RECYCLECOUNT
 
 
     seterr execerr
 
     dummy$=STBL("!SESSIONINFO",ses$+" - idle "+str(usecount))
 
     rem requestSemaphore!.acquire()
-    if !requestSemaphore!.tryAcquire(1,REST_WORKER_IDLEOUT,java.util.concurrent.TimeUnit.SECONDS) then
+    if !requestSemaphore!.tryAcquire(1,REST_TIMEOUT,java.util.concurrent.TimeUnit.SECONDS) then
         rem a timeout has occurred while trying to acquire the semaphore
 
         rem remove the sessions' namespace values

RestBridge.bbj

@@ -218,6 +218,13 @@ class public RestBridge
             ses_list! = BBjAPI().getGlobalNamespace().getValue(uid$+"_list")
         endif
 
+        running_list! = BBjAPI().getGlobalNamespace().getValue(uid$+"_running_list",err=*next)
+        if running_list! = null() then
+            BBjAPI().getGlobalNamespace().setValue(uid$+"_running_list",new java.util.HashSet())
+            running_list! = BBjAPI().getGlobalNamespace().getValue(uid$+"_running_list")
+        endif
+
+
         while 1
             if (ses_list!.empty())
                 servletParams! = #getServletParameters(context!)
@@ -229,6 +236,33 @@ class public RestBridge
                     goto setup_err
                 endif
 
+                if servletParams!.containsKey("REST_MAX_WORKER_COUNT") then
+
+                    REST_MAX_WORKER_COUNT = NUM(STR(servletParams!.get("REST_MAX_WORKER_COUNT")))
+
+                    if (debug) then
+                        System.out.println("REST: Checking for REST_MAX_WORKER_COUNT="+str(REST_MAX_WORKER_COUNT))
+                        System.out.println("REST: "+str(running_list!.size())+" running.")
+                    fi
+
+                    if running_list!.size() >=  REST_MAX_WORKER_COUNT then
+
+                            rem first try to see if they're really all busy
+                            ks! = running_list!.clone().iterator()
+                            while ks!.hasNext()
+                                s$ = ks!.next()
+                                if (!#checkSession(s$)) then
+                                    running_list!.remove(s$)
+                                    System.out.println("****CLEAN OUT FROM RUNNING LIST: "+s$)
+                                fi
+                            wend
+                    fi
+
+                    if running_list!.size() >=  REST_MAX_WORKER_COUNT then
+                            goto too_many_workers_err
+                    fi
+                fi
+
                 ses$ = #newSession(auth$,servletParams!)
                 break
             else
@@ -239,6 +273,8 @@ class public RestBridge
             endif
         wend
 
+        running_list!.add(ses$)
+
         params! = new HashMap()
         it! = request!.getParameterNames().iterator()
         while it!.hasNext()
@@ -326,6 +362,8 @@ class public RestBridge
         else
             answer! = #invoke(ses$,req!)
         fi
+
+        running_list!.remove(ses$)
         ses_list!.push(ses$)
 
         accept$=str(params!.get("_ACCEPT"))
@@ -682,6 +720,20 @@ class public RestBridge
             fi
             response!.sendError(500,"STBLs not set up correctly! Need REST_WD and REST_ADAPTERPGM in config.bbx" )
             #logResponse(req_id$,response!)
+            methodret
+
+        too_many_workers_err:
+            response!.setContentType("text/plain")
+            s! = response!.getOutputStream()
+            s!.write("Too many workers!")
+            if debug then
+                System.out.println("REST: too many workers!" )
+            fi
+            response!.sendError(429,"Too many requests!" )
+            #logResponse(req_id$,response!)
+            methodret
+
+
     methodend
 
 
@@ -882,11 +934,11 @@ class public RestBridge
                 fi
             fi
 
-            namespace!.removeValue(ses$+"_REQUEST")
-            namespace!.removeValue(ses$+"_RESPONSE")
-            namespace!.removeValue(ses$+"_REQUEST_SEM")
-            namespace!.removeValue(ses$+"_RESPONSE_SEM")
-            namespace!.removeValue(ses$+"_SERVLET_PARAMETERS")
+            namespace!.removeValue(ses$+"_REQUEST", err=*next)
+            namespace!.removeValue(ses$+"_RESPONSE", err=*next)
+            namespace!.removeValue(ses$+"_REQUEST_SEM", err=*next)
+            namespace!.removeValue(ses$+"_RESPONSE_SEM", err=*next)
+            namespace!.removeValue(ses$+"_SERVLET_PARAMETERS", err=*next)
             namespace!.removeValue(ses$+"_OUTPUT_HANDLER", err=*next)
             namespace!.removeValue(ses$+"_INPUT_HANDLER", err=*next)
             namespace!.removeValue(ses$+"_THREAD", err=*next)
@@ -900,7 +952,6 @@ class public RestBridge
 
         methodret response!
 
-
         noSes:
             throw  "Session invalid",11
 
@@ -1070,8 +1121,8 @@ class public RestBridge
         parameterNames!.add("REST_TIMEOUT")
         parameterNames!.add("REST_SERVLET_TIMEOUT")
         parameterNames!.add("REST_KILL_WORKER_AT_TIMEOUT")
-        parameterNames!.add("REST_WORKER_IDLEOUT")
         parameterNames!.add("REST_MAX_WORKER_RECYCLECOUNT")
+        parameterNames!.add("REST_MAX_WORKER_COUNT")
         parameterNames!.add("REST_AUTHPGM")
         parameterNames!.add("REST_REQUESTLOG")
         parameterNames!.add("USE_GET_ALLOWED_FILTER")