libyang python APIs (sonic-net#10)

* libyang python APIs
- libyang python wrapper: class sonic_yang
- setup.py to build sonic_yang_mgmt-1.0-py2-none-any.whl
- pytest for the libyang python class: sonic_yang

* Add python wheel package dependency on debs/stretch targets in slave.mk

* Add sonic-yang-mgmt debian package to sonic-broadcom.bin and install libyang python 2 and sonic-yang-mgmt on switch

* Python APIs for libyang
- Add exceptions
- specify data_xpath and schema_xpath
- Add more test cases

* Add error messges for libyang Python APIs

files/build_templates/sonic_debian_extension.j2

@@ -110,6 +110,15 @@ sudo cp {{swsssdk_py2_wheel_path}} $FILESYSTEM_ROOT/$SWSSSDK_PY2_WHEEL_NAME
 sudo https_proxy=$https_proxy LANG=C chroot $FILESYSTEM_ROOT pip install $SWSSSDK_PY2_WHEEL_NAME
 sudo rm -rf $FILESYSTEM_ROOT/$SWSSSDK_PY2_WHEEL_NAME
 
+# Install sonic-yang-mgmt Python 2 package, install dependencies
+sudo dpkg --root=$FILESYSTEM_ROOT -i $debs_path/libyang_*.deb
+sudo dpkg --root=$FILESYSTEM_ROOT -i $debs_path/libyang-cpp_*.deb
+sudo dpkg --root=$FILESYSTEM_ROOT -i $debs_path/python2-yang_*.deb
+SONIC_YANG_MGMT_PY2_WHEEL_NAME=$(basename {{sonic_yang_mgmt_py2_wheel_path}})
+sudo cp {{sonic_yang_mgmt_py2_wheel_path}} $FILESYSTEM_ROOT/$SONIC_YANG_MGMT_PY2_WHEEL_NAME
+sudo https_proxy=$https_proxy LANG=C chroot $FILESYSTEM_ROOT pip install $SONIC_YANG_MGMT_PY2_WHEEL_NAME
+sudo rm -rf $FILESYSTEM_ROOT/$SONIC_YANG_MGMT_PY2_WHEEL_NAME
+
 # Install sonic-platform-common Python 2 package
 PLATFORM_COMMON_PY2_WHEEL_NAME=$(basename {{platform_common_py2_wheel_path}})
 sudo cp {{platform_common_py2_wheel_path}} $FILESYSTEM_ROOT/$PLATFORM_COMMON_PY2_WHEEL_NAME

rules/sonic-yang-mgmt-py2.mk

@@ -3,4 +3,6 @@
 SONIC_YANG_MGMT_PY2 = sonic_yang_mgmt-1.0-py2-none-any.whl
 $(SONIC_YANG_MGMT_PY2)_SRC_PATH = $(SRC_PATH)/sonic-yang-mgmt
 $(SONIC_YANG_MGMT_PY2)_PYTHON_VERSION = 2
+$(SONIC_YANG_MGMT_PY2)_DEBS_DEPENDS = $(LIBYANG)
+
 SONIC_PYTHON_WHEELS += $(SONIC_YANG_MGMT_PY2)

slave.mk

@@ -440,7 +440,8 @@ SONIC_TARGET_LIST += $(addprefix $(PYTHON_DEBS_PATH)/, $(SONIC_PYTHON_STDEB_DEBS
 #     $(SOME_NEW_WHL)_PYTHON_VERSION = 2 (or 3)
 #     $(SOME_NEW_WHL)_DEPENDS = $(SOME_OTHER_WHL1) $(SOME_OTHER_WHL2) ...
 #     SONIC_PYTHON_WHEELS += $(SOME_NEW_WHL)
-$(addprefix $(PYTHON_WHEELS_PATH)/, $(SONIC_PYTHON_WHEELS)) : $(PYTHON_WHEELS_PATH)/% : .platform $$(addsuffix -install,$$(addprefix $(PYTHON_WHEELS_PATH)/,$$($$*_DEPENDS)))
+$(addprefix $(PYTHON_WHEELS_PATH)/, $(SONIC_PYTHON_WHEELS)) : $(PYTHON_WHEELS_PATH)/% : .platform $$(addsuffix -install,$$(addprefix $(PYTHON_WHEELS_PATH)/,$$($$*_DEPENDS))) \
+		$$(addsuffix -install,$$(addprefix $(DEBS_PATH)/,$$($$*_DEBS_DEPENDS)))
 	$(HEADER)
 	pushd $($*_SRC_PATH) $(LOG)
 	# apply series of patches if exist
@@ -624,7 +625,8 @@ $(addprefix $(TARGET_PATH)/, $(SONIC_INSTALLERS)) : $(TARGET_PATH)/% : \
         $(addprefix $(PYTHON_WHEELS_PATH)/,$(SONIC_CONFIG_ENGINE)) \
         $(addprefix $(PYTHON_WHEELS_PATH)/,$(SONIC_PLATFORM_COMMON_PY2)) \
         $(addprefix $(PYTHON_WHEELS_PATH)/,$(REDIS_DUMP_LOAD_PY2)) \
-        $(addprefix $(PYTHON_WHEELS_PATH)/,$(SONIC_PLATFORM_API_PY2))
+        $(addprefix $(PYTHON_WHEELS_PATH)/,$(SONIC_PLATFORM_API_PY2)) \
+        $(addprefix $(PYTHON_WHEELS_PATH)/,$(SONIC_YANG_MGMT_PY2))
 	$(HEADER)
 	# Pass initramfs and linux kernel explicitly. They are used for all platforms
 	export debs_path="$(STRETCH_DEBS_PATH)"
@@ -649,6 +651,7 @@ $(addprefix $(TARGET_PATH)/, $(SONIC_INSTALLERS)) : $(TARGET_PATH)/% : \
 	export platform_common_py2_wheel_path="$(addprefix $(PYTHON_WHEELS_PATH)/,$(SONIC_PLATFORM_COMMON_PY2))"
 	export redis_dump_load_py2_wheel_path="$(addprefix $(PYTHON_WHEELS_PATH)/,$(REDIS_DUMP_LOAD_PY2))"
 	export install_debug_image="$(INSTALL_DEBUG_TOOLS)"
+	export sonic_yang_mgmt_py2_wheel_path="$(addprefix $(PYTHON_WHEELS_PATH)/,$(SONIC_YANG_MGMT_PY2))"
 
 	$(foreach docker, $($*_DOCKERS),\
 		export docker_image="$(docker)"

src/sonic-yang-mgmt/setup.py

@@ -7,17 +7,17 @@
 from setuptools.command.build_py import build_py
 from os import system
 from sys import exit
+import pytest
+import os
 
 # important reuirements parameters
 build_requirements = ['../../target/debs/stretch/libyang_1.0.73_amd64.deb',
-                      '../../target/debs/stretch/libyang-cpp_1.0.73_amd64.deb',
-                      '../../target/debs/stretch/python2-yang_1.0.73_amd64.deb']
+                        '../../target/debs/stretch/libyang-cpp_1.0.73_amd64.deb',
+                        '../../target/debs/stretch/python2-yang_1.0.73_amd64.deb',]
 
-install_requirements = []
+setup_requirements = ['pytest-runner']
 
-setup_requirements = ['pytest-runner',]
-
-test_requirements = ['pytest>=3', ]
+test_requirements = ['pytest>=3']
 
 # read me
 with open('README.rst') as readme_file:
@@ -39,9 +39,10 @@ def run (self):
             if 'target/debs'in req:
                 pkg_install_cmd = "sudo dpkg -i {}".format(req)
                 if (system(pkg_install_cmd)):
-                    print("{} installed".format(req))
+                    print("{} installation failed".format(req))
+                    exit(1)
                 else:
-                    print("{} installtion failed".format(req))
+                    print("{} installed".format(req))
 
         #  run tests for yang models
         test_yang_cmd = "python {} -f {} -y {}".format(yang_test_py, test_yangJson_file, yang_model_dir)
@@ -53,8 +54,13 @@ def run (self):
             print("YANG Tests passed\n")
 
         # Continue usual build steps
-        build_py.run(self)
+        # run pytest for libyang python APIs
+        self.pytest_args = []
+        errno = pytest.main(self.pytest_args)
+        if (errno):
+            exit(errno)
 
+        build_py.run(self)
 
 setup(
     cmdclass={
@@ -77,12 +83,13 @@ def run (self):
         'Programming Language :: Python :: 3.8',
     ],
     description="Package contains YANG models for sonic.",
-    install_requires=install_requirements,
+    tests_require = test_requirements,
     license="GNU General Public License v3",
     long_description=readme + '\n\n',
     include_package_data=True,
     keywords='sonic_yang_mgmt',
     name='sonic_yang_mgmt',
+    py_modules=['sonic_yang'],
     packages=find_packages(),
     setup_requires=setup_requirements,
     version='1.0',