sonic-config-engine uses libswsscommon instead of swsssdk (#6406)

**- Why I did it**
swsssdk will be deprecated. Migrate sonic-config-engine to use libswsscommon library instead

**- How to verify it**
Unit test

platform/vs/docker-sonic-vs/start.sh

@@ -31,6 +31,11 @@ if [[ -f /usr/share/sonic/virtual_chassis/default_config.json ]]; then
     CHASS_CFG="-j /usr/share/sonic/virtual_chassis/default_config.json"
 fi
 
+# Note: libswsscommon requires a dabase_config file in /var/run/redis/sonic-db/
+# Prepare this file before any dependent application, such as sonic-cfggen
+mkdir -p /var/run/redis/sonic-db
+cp /etc/default/sonic-db/database_config.json /var/run/redis/sonic-db/
+
 SYSTEM_MAC_ADDRESS=$(ip link show eth0 | grep ether | awk '{print $2}')
 sonic-cfggen -a '{"DEVICE_METADATA":{"localhost": {"mac": "'$SYSTEM_MAC_ADDRESS'", "buffer_model": "traditional"}}}' $CHASS_CFG --print-data > /etc/sonic/init_cfg.json
 
@@ -68,9 +73,6 @@ else
    echo "10.8.1.200 redis_chassis.server" >> /etc/hosts
 fi
 
-mkdir -p /var/run/redis/sonic-db
-cp /etc/default/sonic-db/database_config.json /var/run/redis/sonic-db/
-
 supervisorctl start redis-server
 
 start_chassis_db=`sonic-cfggen -v DEVICE_METADATA.localhost.start_chassis_db -y $chassisdb_cfg_file`

rules/sonic-config.mk

@@ -2,15 +2,17 @@
 
 SONIC_CONFIG_ENGINE_PY2 = sonic_config_engine-1.0-py2-none-any.whl
 $(SONIC_CONFIG_ENGINE_PY2)_SRC_PATH = $(SRC_PATH)/sonic-config-engine
-$(SONIC_CONFIG_ENGINE_PY2)_DEPENDS += $(SWSSSDK_PY2) $(SONIC_PY_COMMON_PY2)
+$(SONIC_CONFIG_ENGINE_PY2)_DEPENDS += $(SONIC_PY_COMMON_PY2)
+$(SONIC_CONFIG_ENGINE_PY2)_DEBS_DEPENDS += $(PYTHON_SWSSCOMMON)
 $(SONIC_CONFIG_ENGINE_PY2)_PYTHON_VERSION = 2
 SONIC_PYTHON_WHEELS += $(SONIC_CONFIG_ENGINE_PY2)
 
 # SONIC_CONFIG_ENGINE_PY3 package
 
 SONIC_CONFIG_ENGINE_PY3 = sonic_config_engine-1.0-py3-none-any.whl
 $(SONIC_CONFIG_ENGINE_PY3)_SRC_PATH = $(SRC_PATH)/sonic-config-engine
-$(SONIC_CONFIG_ENGINE_PY3)_DEPENDS += $(SWSSSDK_PY3) $(SONIC_PY_COMMON_PY3)
+$(SONIC_CONFIG_ENGINE_PY3)_DEPENDS += $(SONIC_PY_COMMON_PY3)
+$(SONIC_CONFIG_ENGINE_PY3)_DEBS_DEPENDS += $(PYTHON3_SWSSCOMMON)
 # Synthetic dependency to avoid building the Python 2 and 3 packages
 # simultaneously and any potential conflicts which may arise
 $(SONIC_CONFIG_ENGINE_PY3)_DEPENDS += $(SONIC_CONFIG_ENGINE_PY2)

src/sonic-config-engine/portconfig.py

@@ -5,7 +5,7 @@
     import re
     import sys
 
-    from swsssdk import ConfigDBConnector
+    from swsscommon.swsscommon import ConfigDBConnector
     from sonic_py_common import device_info
 except ImportError as e:
     raise ImportError("%s - required module not found" % str(e))

src/sonic-config-engine/redis_bcc.py

@@ -19,11 +19,11 @@ def load_bytecode(self, bucket):
             return
         code = self._client.get(self._client.LOGLEVEL_DB, self.REDIS_HASH, bucket.key)
         if code is not None:
-            bucket.bytecode_from_string(b64decode(code))
+            bucket.bytecode_from_string(b64decode(code.encode()))
 
     def dump_bytecode(self, bucket):
         if self._client is None:
             return
         self._client.set(self._client.LOGLEVEL_DB, self.REDIS_HASH,
-                         bucket.key, b64encode(bucket.bytecode_to_string()))
+                         bucket.key, b64encode(bucket.bytecode_to_string()).decode())
 

src/sonic-config-engine/sonic-cfggen

@@ -43,7 +43,7 @@ from portconfig import get_port_config, get_breakout_mode
 from redis_bcc import RedisBytecodeCache
 from sonic_py_common.multi_asic import get_asic_id_from_name, is_multi_asic
 from sonic_py_common import device_info
-from swsssdk import SonicV2Connector, ConfigDBConnector, SonicDBConfig, ConfigDBPipeConnector
+from swsscommon.swsscommon import SonicV2Connector, ConfigDBConnector, SonicDBConfig, ConfigDBPipeConnector
 
 
 PY3x = sys.version_info >= (3, 0)