Fix coils and discrete input register initialization (#20)

Try fixing issue #19

Author: cybcon

Dockerfile

@@ -8,17 +8,16 @@ LABEL site.local.os.version="3.17"
 LABEL site.local.runtime.name="Python"
 LABEL site.local.runtime.version="3.10.9"
 LABEL site.local.program.name="Python Modbus TCP Server"
-LABEL site.local.program.version="1.1.3"
+LABEL site.local.program.version="1.1.4"
 
-RUN addgroup -g 1000 -S pythonuser \
-    && adduser -u 1000 -S pythonuser -G pythonuser \
-    && mkdir -p /app \
-    && pip3 install --no-cache-dir 'pymodbus>=2,<3'
-COPY --chown=root:root app/* /app/
+COPY --chown=root:root /src /
+
+RUN pip3 install --no-cache-dir -r /requirements.txt
 
-USER pythonuser
 EXPOSE 5020/tcp
 
+USER 1434:1434
+
 # Start Server
 ENTRYPOINT ["python", "-u", "/app/modbus_server.py"]
 CMD ["-f", "/app/modbus_server.json"]

examples/test.json

@@ -0,0 +1,44 @@
+{
+"server": {
+  "listenerAddress": "0.0.0.0",
+  "listenerPort": 5020,
+  "tlsParams": {
+    "description": "path to certificate and private key to enable tls",
+    "privateKey": null,
+    "certificate": null
+    },
+  "logging": {
+    "format": "%(asctime)-15s %(threadName)-15s  %(levelname)-8s %(module)-15s:%(lineno)-8s %(message)s",
+    "logLevel": "DEBUG"
+    }
+  },
+"registers": {
+  "description": "initial values for the register types",
+  "zeroMode": false,
+  "initializeUndefinedRegisters": true,
+  "discreteInput": {
+    "1": true,
+    "2": false,
+    "3": true,
+    "4": false
+  },
+  "coils": {
+    "1": false,
+    "2": true,
+    "3": true,
+    "4": false
+  },
+  "holdingRegister": {
+    "1": "0xCC01",
+    "2": "0xCC02",
+    "3": "0xCC03",
+    "4": "0xCC04"
+    },
+  "inputRegister": {
+    "1": "0xDD01",
+    "2": "0xDD02",
+    "3": "0xDD03",
+    "4": "0xDD04"
+    }
+  }
+}

app/modbus_server.json renamed to src/app/modbus_server.json

@@ -3,6 +3,8 @@
 Modbus TCP server script for debugging
 Author: Michael Oberdorf IT-Consulting
 Datum: 2020-03-30
+Last modified by: Hackergarden Meetup@Codecentric
+Last modified at: 2023-11-07
 *************************************************************************** """
 import sys
 import os
@@ -18,8 +20,8 @@
 import json
 
 # default configuration file path
-config_file='/opt/modbus_server/etc/modbus_server.json'
-VERSION='1.1.3'
+config_file='/app/modbus_server.json'
+VERSION='1.1.4'
 """
 ###############################################################################
 # F U N C T I O N S
@@ -39,7 +41,7 @@ def get_ip_address():
         pass
     return(ipaddr)
 
-def run_server(listener_address='0.0.0.0', listener_port=5020, tls_cert=None, tls_key=None, zeroMode=False, discreteInputs=dict(), coils=dict(), holdingRegisters=dict(), inputRegisters=dict()):
+def run_server(listener_address: str = '0.0.0.0', listener_port: int = 5020, tls_cert: str = None, tls_key: str = None, zeroMode: bool = False, discreteInputs: dict = dict(), coils: dict = dict(), holdingRegisters: dict = dict(), inputRegisters: dict = dict()):
     """
     Run the modbus server(s)
     @param listener_address: string, IP address to bind the listener (default: '0.0.0.0')
@@ -139,10 +141,11 @@ def run_server(listener_address='0.0.0.0', listener_port=5020, tls_cert=None, tl
         # StartTcpServer(context, identity=identity, framer=ModbusRtuFramer, address=(listener_address, listener_port))
 
 
-def prepareRegister(register, initializeUndefinedRegisters=False):
+def prepareRegister(register: dict, initType: str, initializeUndefinedRegisters: bool = False) -> dict:
     """
     Function to prepare the register to have the correct data types
     @param register: dict(), the register dictionary, loaded from json file
+    @param initType: str(), how to initialize the register values 'boolean' or 'word'
     @param initializeUndefinedRegisters: boolean, fill undefined registers with 0x00 (default: False)
     @return: dict(), register with correct data types
     """
@@ -160,17 +163,34 @@ def prepareRegister(register, initializeUndefinedRegisters=False):
 
         val = register[key]
         valOut = val
-        if isinstance(val, str) and str(val)[0:2] == '0x':
+        if initType == 'word' and isinstance(val, str) and str(val)[0:2] == '0x':
             valOut = int(val, 16)
             log.debug('  Transform value for register: ' + str(keyOut) + ' from: ' + str(val) + ' ('+ str(type(key)) + ') to: ' + str(valOut) + ' (' + str(type(valOut)) + ')')
+        elif initType == 'boolean':
+            if isinstance(val, bool):
+              valOut = val
+              log.debug('  Set register: ' + str(keyOut) + ' to: ' + str(valOut) + ' (' + str(type(valOut)) + ')')
+            elif isinstance(val, int):
+              if val == 0:
+                valOut = False
+              else:
+                valOut = True
+              log.debug('  Transform value for register: ' + str(keyOut) + ' from: ' + str(val) + ' ('+ str(type(key)) + ') to: ' + str(valOut) + ' (' + str(type(valOut)) + ')')
         outRegister[keyOut] = valOut
 
     if initializeUndefinedRegisters:
-        log.debug('  Fill undefined registers with 0x00')
+        if initType == 'word':
+          log.debug('  Fill undefined registers with 0x00')
+        elif initType == 'boolean':
+          log.debug('  Fill undefined registers with False')
         for r in range(0, 65536, 1):
             if r not in outRegister:
+              if initType == 'word':
                 #log.debug('  Initialize address: ' + str(r) + ' with 0')
                 outRegister[r] = 0
+              elif initType == 'boolean':
+                #log.debug('  Initialize address: ' + str(r) + ' with False')
+                outRegister[r] = False
 
     return(outRegister)
 
@@ -194,7 +214,8 @@ def prepareRegister(register, initializeUndefinedRegisters=False):
         config_file=args.config_file
 
 # read configuration file
-with open(config_file, encoding='utf-8') as f: CONFIG = json.load(f)
+with open(config_file, encoding='utf-8') as f:
+  CONFIG = json.load(f)
 
 
 # Initialize logger
@@ -209,15 +230,16 @@ def prepareRegister(register, initializeUndefinedRegisters=False):
 else: log.setLevel(logging.INFO)
 
 
-# be sure the data types within the dictionaries are correct (json will only allow strings as keys)
-discreteInputs = prepareRegister(CONFIG['registers']['discreteInput'], CONFIG['registers']['initializeUndefinedRegisters'])
-coils=prepareRegister(CONFIG['registers']['coils'], CONFIG['registers']['initializeUndefinedRegisters'])
-holdingRegisters=prepareRegister(CONFIG['registers']['holdingRegister'], CONFIG['registers']['initializeUndefinedRegisters'])
-inputRegisters=prepareRegister(CONFIG['registers']['inputRegister'], CONFIG['registers']['initializeUndefinedRegisters'])
-
-
 # start the server
 log.info('Starting Modbus TCP Server, v' + str(VERSION))
+log.debug('Loaded successfully the configuration file: {}'.format(config_file))
+
+# be sure the data types within the dictionaries are correct (json will only allow strings as keys)
+discreteInputs = prepareRegister(register = CONFIG['registers']['discreteInput'], initType='boolean', initializeUndefinedRegisters = CONFIG['registers']['initializeUndefinedRegisters'])
+coils=prepareRegister(register = CONFIG['registers']['coils'], initType='boolean', initializeUndefinedRegisters = CONFIG['registers']['initializeUndefinedRegisters'])
+holdingRegisters=prepareRegister(register = CONFIG['registers']['holdingRegister'], initType='word', initializeUndefinedRegisters = CONFIG['registers']['initializeUndefinedRegisters'])
+inputRegisters=prepareRegister(register = CONFIG['registers']['inputRegister'], initType='word', initializeUndefinedRegisters = CONFIG['registers']['initializeUndefinedRegisters'])
+
 # try to get the interface IP address
 localIPAddr = get_ip_address()
 if localIPAddr != '': log.info('Outbund device IP address is: ' + localIPAddr)

app/modbus_server.py renamed to src/app/modbus_server.py

@@ -0,0 +1,2 @@
+pip >= 23
+pymodbus >= 2, < 3