napalm 简单介绍
napalm （Network Automation and Programmability Abstraction Layer with Multivendor support）顾名思义，是一个给多个厂家设备都抽象了相同名字方法的 网络自动化 python库.
官方参考文档：https://napalm.readthedocs.io/en/latest/
一、导入napalm
```python
from napalm import *
```
表示导入naplam这个包，只会导入2个东西(python中__all__决定的)：
```python
##关键源码 napalm/__init__.py
__all__ = ("get_network_driver", "SUPPORTED_DRIVERS")
```
get_network_driver 表示获取具体厂商驱动的 方法
SUPPORTED_DRIVERS 表示驱动已经支持哪些厂家，是一个列表, 后续自定义了驱动 把名字加上即可
二、获取厂家(设备型号)驱动
获取具体厂商的驱动(以思科的ios为例)：
```python
from napalm import *
ios_driver = get_network_driver(‘ios‘)
```
get_network_driver 根据输入的驱动名字来导入对应的包（napalm实际上是一个包含多个包的包）
```python
## 关键代码 napalm/base/__init__.py
def get_network_driver(name, prepend=True):
if name == "mock":
return MockDriver
# 这里主要是对输入内容合法性进行过滤 #
if not (isinstance(name, str) and len(name) > 0):
raise ModuleImportError("Please provide a valid driver name.")
# 根据输入对驱动名进行导包 importlib #
# Only lowercase allowed
name = name.lower()
# Try to not raise error when users requests IOS-XR for e.g.
module_install_name = name.replace("-", "")
community_install_name = "napalm_{name}".format(name=module_install_name)
custom_install_name = "custom_napalm.{name}".format(name=module_install_name)
# Can also request using napalm_[SOMETHING]
if "napalm" not in module_install_name and prepend is True:
module_install_name = "napalm.{name}".format(name=module_install_name)
# Order is custom_napalm_os (local only) -> napalm.os (core) -> napalm_os (community)
for module_name in [
custom_install_name,
module_install_name,
community_install_name,
]:
try:
module = importlib.import_module(module_name)
break
except ImportError as e:
message = str(e)
if "No module named" in message:
# py2 doesn‘t have ModuleNotFoundError exception
failed_module = message.split()[-1]
if failed_module.replace("‘", "") in module_name:
continue
raise e
else:
raise ModuleImportError(
‘Cannot import "{install_name}". Is the library installed?‘.format(
install_name=name
)
)
# 导入模块的对象中必须包含NetworkDriver子类(后续自定义驱动的话，也要继承NetworkDriver)， 然后返回对应的 驱动class #
for name, obj in inspect.getmembers(module):
if inspect.isclass(obj) and issubclass(obj, NetworkDriver):
return obj
# 如果输入的驱动名字 没有匹配上，那么会抛出异常 #
# looks like you don‘t have any Driver class in your module...
raise ModuleImportError(
‘No class inheriting "napalm.base.base.NetworkDriver" found in "{install_name}".‘.format(
install_name=module_install_name
)
)```
```
四、查看ios驱动实现了哪些方法
```python
from napalm import *
ios_driver = get_network_driver(‘ios‘)
print(list(i for i in dir(ios_driver) if not i.startswith(‘_‘))) # 查看ios_driver实现的方法
```
输出:
```python
[‘bgp_time_conversion‘, ‘cli‘, ‘close‘, ‘commit_config‘, ‘compare_config‘, ‘compliance_report‘, ‘confirm_commit‘, ‘connection_tests‘, ‘dest_file_system‘, ‘discard_config‘, ‘get_arp_table‘, ‘get_bgp_config‘, ‘get_bgp_neighbors‘, ‘get_bgp_neighbors_detail‘, ‘get_config‘, ‘get_environment‘, ‘get_facts‘, ‘get_firewall_policies‘, ‘get_interfaces‘, ‘get_interfaces_counters‘, ‘get_interfaces_ip‘, ‘get_ipv6_neighbors_table‘, ‘get_lldp_neighbors‘, ‘get_lldp_neighbors_detail‘, ‘get_mac_address_table‘, ‘get_network_instances‘, ‘get_ntp_peers‘, ‘get_ntp_servers‘, ‘get_ntp_stats‘, ‘get_optics‘, ‘get_probes_config‘, ‘get_probes_results‘, ‘get_route_to‘, ‘get_snmp_information‘, ‘get_users‘, ‘get_vlans‘, ‘has_pending_commit‘, ‘is_alive‘, ‘load_merge_candidate‘, ‘load_replace_candidate‘, ‘load_template‘, ‘open‘, ‘parse_uptime‘, ‘ping‘, ‘post_connection_tests‘, ‘pre_connection_tests‘, ‘rollback‘, ‘traceroute‘]
```
五、实际上napalm在base包中，也就是父类NetworkDriver中定义了很多方法，
这些方法实际上是每个厂家驱动都要实现的，如果没有实现 调用时会抛出"为定义的错误"。
同时，NetworkDriver中定义的方法，也是我们后续自定义其他厂家驱动时 需要去覆盖实现的具体方法。
```python
import napalm
list1 = list(i for i in dir(napalm.base.NetworkDriver) if not i.startswith(‘_‘))
print(list1)
# output #
[‘cli‘, ‘close‘, ‘commit_config‘, ‘compare_config‘, ‘compliance_report‘, ‘confirm_commit‘, ‘connection_tests‘, ‘discard_config‘, ‘get_arp_table‘, ‘get_bgp_config‘, ‘get_bgp_neighbors‘, ‘get_bgp_neighbors_detail‘, ‘get_config‘, ‘get_environment‘, ‘get_facts‘, ‘get_firewall_policies‘, ‘get_interfaces‘, ‘get_interfaces_counters‘, ‘get_interfaces_ip‘, ‘get_ipv6_neighbors_table‘, ‘get_lldp_neighbors‘, ‘get_lldp_neighbors_detail‘, ‘get_mac_address_table‘, ‘get_network_instances‘, ‘get_ntp_peers‘, ‘get_ntp_servers‘, ‘get_ntp_stats‘, ‘get_optics‘, ‘get_probes_config‘, ‘get_probes_results‘, ‘get_route_to‘, ‘get_snmp_information‘, ‘get_users‘, ‘get_vlans‘, ‘has_pending_commit‘, ‘is_alive‘, ‘load_merge_candidate‘, ‘load_replace_candidate‘, ‘load_template‘, ‘open‘, ‘ping‘, ‘post_connection_tests‘, ‘pre_connection_tests‘, ‘rollback‘, ‘traceroute‘]```