CommandGenerator.getNext() & .getBulk() methods now support the

maxCalls kwarg to limit the maximum number of request-response
iterations to perform

3 files changed, 53 insertions, 29 deletions

diff --git a/CHANGES b/CHANGES
index f55229d..bb09e2c 100644
--- a/CHANGES
+++ b/CHANGES
@@ -152,6 +152,8 @@ Revision 4.2.5
   to facilitate authentication data management in user applications.
 - Oneliner transport target classes now support the getTransportInfo()
   method that returns network addresses used on protocol level.
+- Oneliner CommandGenerator.getNext() & .getBulk() methods now support the
+  maxCalls kwarg to limit the maximum number of iterations to perform.
 - The config.addSocketTransport() helper renamed into config.addTransport()
   and improved by automatically instantiating compatible TransportDispatcher
   making it dispatcher-agnostic. As an additional bonus, application may not
diff --git a/examples/v3arch/oneliner/manager/cmdgen/getbulk-v3-with-custom-mib-path-and-options.py b/examples/v3arch/oneliner/manager/cmdgen/getbulk-v3-with-custom-mib-path-and-options.py
index f85cf6b..a0f0f29 100644
--- a/examples/v3arch/oneliner/manager/cmdgen/getbulk-v3-with-custom-mib-path-and-options.py
+++ b/examples/v3arch/oneliner/manager/cmdgen/getbulk-v3-with-custom-mib-path-and-options.py
@@ -8,7 +8,8 @@
 # * to an Agent at demo.snmplabs.com:161
 # * for all OIDs past TCP-MIB::tcpConnTable
 # * TCP-MIB will be searched by a user-specified path
-# * run till end-of-mib condition is reported by Agent OR maxRows == 20
+# * run till end-of-mib condition is reported by Agent OR maxRows == 100 OR
+#   maxCalls == 10 request-response interactions occur
 # * ignoring non-increasing OIDs whenever reported by Agent
 #
 # make sure IF-MIB.py is search path
@@ -22,7 +23,7 @@ errorIndication, errorStatus, errorIndex, varBindTable = cmdGen.bulkCmd(
     cmdgen.UdpTransportTarget(('demo.snmplabs.com', 161)),
     0, 50,
     cmdgen.MibVariable('TCP-MIB', 'tcpConnTable').addMibSource('/tmp/mymibs'),
-    lexicographicMode=True, maxRows=100, ignoreNonIncreasingOid=True
+    lexicographicMode=True, maxRows=100, maxCalls=10,ignoreNonIncreasingOid=True
 )
 
 if errorIndication:
diff --git a/pysnmp/entity/rfc3413/oneliner/cmdgen.py b/pysnmp/entity/rfc3413/oneliner/cmdgen.py
index 65bc2c7..1e91042 100644
--- a/pysnmp/entity/rfc3413/oneliner/cmdgen.py
+++ b/pysnmp/entity/rfc3413/oneliner/cmdgen.py
@@ -626,18 +626,6 @@ class CommandGenerator:
                 appReturn['varBindTable'] = varBindTotalTable
                 return
             else:
-                if maxRows and len(varBindTotalTable) >= maxRows or \
-                        hasattr(self, 'maxRows') and self.maxRows and \
-                        len(varBindTotalTable) >= self.maxRows:
-                    appReturn['errorIndication'] = errorIndication
-                    appReturn['errorStatus'] = errorStatus
-                    appReturn['errorIndex'] = errorIndex
-                    if hasattr(self, 'maxRows'):
-                        appReturn['varBindTable'] = varBindTotalTable[:self.maxRows]
-                    else:
-                        appReturn['varBindTable'] = varBindTotalTable[:maxRows]
-                    return
-                
                 varBindTableRow = varBindTable and varBindTable[-1] or varBindTable
                 for idx in range(len(varBindTableRow)):
                     name, val = varBindTableRow[idx]
@@ -660,6 +648,27 @@ class CommandGenerator:
                 
                 varBindTotalTable.extend(varBindTable)
 
+                if maxRows and len(varBindTotalTable) >= maxRows or \
+                        hasattr(self, 'maxRows') and self.maxRows and \
+                        len(varBindTotalTable) >= self.maxRows:
+                    appReturn['errorIndication'] = errorIndication
+                    appReturn['errorStatus'] = errorStatus
+                    appReturn['errorIndex'] = errorIndex
+                    if hasattr(self, 'maxRows'):
+                        appReturn['varBindTable'] = varBindTotalTable[:self.maxRows]
+                    else:
+                        appReturn['varBindTable'] = varBindTotalTable[:maxRows]
+                    return
+ 
+                if maxCalls[0] > 0:
+                    maxCalls[0] -= 1
+                    if maxCalls[0] == 0:
+                      appReturn['errorIndication'] = errorIndication
+                      appReturn['errorStatus'] = errorStatus
+                      appReturn['errorIndex'] = errorIndex
+                      appReturn['varBindTable'] = varBindTotalTable
+                      return
+
                 return 1 # continue table retrieval
 
         lookupNames = kwargs.get('lookupNames', False)        
@@ -668,6 +677,7 @@ class CommandGenerator:
         contextName = kwargs.get('contextName', null)
         lexicographicMode = kwargs.get('lexicographicMode', False)
         maxRows = kwargs.get('maxRows', 0)
+        maxCalls = [ kwargs.get('maxCalls', 0) ]
         ignoreNonIncreasingOid = kwargs.get('ignoreNonIncreasingOid', False)
 
         varBindHead = [ univ.ObjectIdentifier(x[0]) for x in self.__asynCmdGen.makeReadVarBinds(varNames) ]
@@ -714,22 +724,8 @@ class CommandGenerator:
                     else:
                         break
 
-                varBindTotalTable.extend(varBindTable) # XXX out of table 
-                                                       # rows possible
-
-                if maxRows and len(varBindTotalTable) >= maxRows or \
-                        hasattr(self, 'maxRows') and self.maxRows and \
-                        len(varBindTotalTable) >= self.maxRows:  # obsolete
-                    appReturn['errorIndication'] = errorIndication
-                    appReturn['errorStatus'] = errorStatus
-                    appReturn['errorIndex'] = errorIndex
-                    if hasattr(self, 'maxRows'):
-                        appReturn['varBindTable'] = varBindTotalTable[:self.maxRows]
-                    else:
-                        appReturn['varBindTable'] = varBindTotalTable[:maxRows]
-                    return
-
                 varBindTableRow = varBindTable and varBindTable[-1] or varBindTable
+
                 for idx in range(len(varBindTableRow)):
                     name, val = varBindTableRow[idx]
                     if not isinstance(val, univ.Null):
@@ -748,6 +744,30 @@ class CommandGenerator:
                     appReturn['varBindTable'] = varBindTotalTable
                     return
 
+                varBindTotalTable.extend(varBindTable) # XXX out of table 
+                                                       # rows possible
+
+                if maxCalls[0] > 0:
+                    maxCalls[0] -= 1
+                    if maxCalls[0] == 0:
+                      appReturn['errorIndication'] = errorIndication
+                      appReturn['errorStatus'] = errorStatus
+                      appReturn['errorIndex'] = errorIndex
+                      appReturn['varBindTable'] = varBindTotalTable
+                      return
+ 
+                if maxRows and len(varBindTotalTable) >= maxRows or \
+                        hasattr(self, 'maxRows') and self.maxRows and \
+                        len(varBindTotalTable) >= self.maxRows:  # obsolete
+                    appReturn['errorIndication'] = errorIndication
+                    appReturn['errorStatus'] = errorStatus
+                    appReturn['errorIndex'] = errorIndex
+                    if hasattr(self, 'maxRows'):
+                        appReturn['varBindTable'] = varBindTotalTable[:self.maxRows]
+                    else:
+                        appReturn['varBindTable'] = varBindTotalTable[:maxRows]
+                    return
+
                 return 1 # continue table retrieval
 
         lookupNames = kwargs.get('lookupNames', False)        
@@ -756,6 +776,7 @@ class CommandGenerator:
         contextName = kwargs.get('contextName', null)
         lexicographicMode = kwargs.get('lexicographicMode', False)
         maxRows = kwargs.get('maxRows', 0)
+        maxCalls = [ kwargs.get('maxCalls', 0) ]
         ignoreNonIncreasingOid = kwargs.get('ignoreNonIncreasingOid', False)
 
         varBindHead = [ univ.ObjectIdentifier(x[0]) for x in self.__asynCmdGen.makeReadVarBinds(varNames) ]