Python读取JSON设备列表实现Netmiko SSH及过滤指定JSON字段

Let's break down your two problems and walk through practical solutions—these are super common when working with API-sourced device data and network automation!

Problem 1: Fixing TypeError: string indices must be integers When Connecting Devices #

That error pops up because your script is trying to treat a string like a dictionary. Here's the typical scenario:

Your JSON file isn't a pure array of device dictionaries. Instead, it has an outer wrapper key (like {"devices": [...]}), and you're accidentally iterating over the wrapper keys (strings like "devices") instead of the actual device list.

Solution: Extract the Device Array First #

First, identify the outer key in your JSON that holds the device list (common names are devices, device_list, result, etc.). Then extract that array before looping with Netmiko.

Example corrected script:

import json
from netmiko import ConnectHandler

# Load your JSON file (or replace with API response parsing)
with open("your_api_devices.json", "r") as f:
    api_response = json.load(f)

# Extract the actual device array—replace "devices" with your JSON's outer key
device_list = api_response.get("devices", [])

# Now loop through the device dictionary array safely
for device in device_list:
    try:
        conn = ConnectHandler(
            ip=device["ip"],
            username=device["username"],
            password=device["password"],
            device_type="cisco_ios"  # Adjust to your device type (e.g., "juniper_junos")
        )
        # Run your desired commands here
        print(f"Successfully connected to {device['ip']}")
        output = conn.send_command("show run | include hostname")
        print(output)
        conn.disconnect()
    except Exception as e:
        print(f"Connection failed for {device['ip']}: {str(e)}")

• Use get() to avoid crashes if the outer key doesn't exist (it returns an empty list as a fallback).
• Double-check your JSON structure with a tool like jq or a JSON viewer to confirm the outer key name.

Problem 2: Filtering JSON to Keep Only Required Fields #

To generate a JSON file with just username, ip, and password, you'll need to iterate over the raw device data and build a new list of dictionaries with only those fields.

Solution: Build a Filtered Device List #

You can do this with a simple loop or a concise list comprehension—both work, pick the one you find more readable.

Option 1: Explicit Loop (Great for clarity)

import json

# Load raw API data
with open("raw_api_response.json", "r") as f:
    raw_data = json.load(f)

# Extract the device array first (same as Problem 1)
raw_devices = raw_data.get("devices", [])

# Filter to keep only the fields you need
filtered_devices = []
for device in raw_devices:
    # Use get() to avoid KeyError if a field is missing in some devices
    filtered_device = {
        "ip": device.get("ip"),
        "username": device.get("username"),
        "password": device.get("password")
    }
    # Optional: Skip devices with missing required fields
    if all(filtered_device.values()):
        filtered_devices.append(filtered_device)

# Save the filtered data to a new JSON file
with open("filtered_devices.json", "w") as f:
    # Save as an object with a "devices" key, or just the array if preferred
    json.dump({"devices": filtered_devices}, f, indent=4)

Option 2: List Comprehension (More concise)

# Same setup as above, then:
filtered_devices = [
    {key: device[key] for key in ["ip", "username", "password"] if key in device}
    for device in raw_devices
]

# Save the filtered list
with open("filtered_devices.json", "w") as f:
    json.dump(filtered_devices, f, indent=4)

• The if key in device check ensures you don't get a KeyError if a device is missing a field.
• Use indent=4 to make the output JSON human-readable.

内容的提问来源于stack exchange，提问作者chenoi