PySMI (lextudio)

1.4.3 · active · verified Fri Apr 17

PySMI (lextudio) is a pure-Python library for parsing and converting SNMP/SMI MIB definitions. It provides tools to work with MIB files, resolve dependencies, and generate various output formats, including PySNMP-compatible Python modules. The current version is 1.4.3 and it maintains an active, though not rapid, release cadence.

Common errors

```
ModuleNotFoundError: No module named 'pysmi'
```
cause The `pysmi-lextudio` package was not installed, or an outdated `pysmi` package (the old one) was installed, leading to incorrect import paths.

fix Ensure you have installed the correct package: `pip install pysmi-lextudio`. If you previously installed `pysmi`, uninstall it first: `pip uninstall pysmi`.
```
pysmi.error.SmiError: MIB module "SOME-DEPENDENT-MIB" not found
```
cause The parser could not locate a required MIB module that the MIB being processed imports from. This usually means the dependent MIB file is missing from the configured search paths.

fix Add the directory containing `SOME-DEPENDENT-MIB.mib` (and any other dependencies) to your MIB builder's sources using `mibBuilder.addMibSources(FileReader('/path/to/mib/directory'))`.
```
UnicodeDecodeError: 'utf-8' codec can't decode byte 0x... in position ...: invalid start byte
```
cause A MIB file is not encoded in UTF-8, but PySMI attempts to read it as such by default, leading to a decoding failure.

fix When adding `FileReader` sources, specify the correct encoding if known: `FileReader('/path/to/mib/directory', encoding='iso-8859-1')` (replace `iso-8859-1` with the actual encoding if different).

Warnings

breaking Users upgrading from `pysmi` 0.x to 1.x (or `pysmi-lextudio` 1.x) will encounter significant API changes due to a complete refactoring. Code written for 0.x versions is incompatible with 1.x.
Fix: Refer to the `pysmi-lextudio` 1.x documentation and examples for updated API usage, particularly around `SmiStarParser`, `SmiBuilder`, and `CodeGen` classes.
gotcha PySMI requires all dependent MIB modules to be available in the provided MIB sources. If a MIB imports symbols from another MIB not found in the search paths, a `SmiError: MIB module '...' not found` will be raised. This includes common base MIBs like `SNMPv2-SMI` or `RFC1213-MIB`.
Fix: Ensure all necessary MIB files, including standard RFCs, are present in the directories added via `mibBuilder.addMibSources(FileReader('/path/to/mib/directory'))`.
gotcha There is an older, unmaintained `pysmi` package on PyPI. Always use `pysmi-lextudio` for the actively developed and supported version. Installing the wrong package will result in `ModuleNotFoundError` or outdated functionality.
Fix: Verify your installation command is `pip install pysmi-lextudio`. If you encounter issues, uninstall `pysmi` if present (`pip uninstall pysmi`) and then install `pysmi-lextudio`.

Install

pip install pysmi-lextudio Install stable version

Imports

SmiStarParser
```
from pysmi.parser import SmiStarParser
```
SmiBuilder
```
from pysmi.builder import SmiBuilder
```
PySnmpCodeGen
```
from pysmi.codegen import PySnmpCodeGen
```
FileReader
```
from pysmi.reader import FileReader
```

Quickstart

This quickstart demonstrates how to parse a simple MIB file using PySMI. It creates a temporary MIB file and a dummy 'SNMPv2-SMI' for basic dependency resolution, then uses `SmiBuilder` and `FileReader` to load and verify the MIB module.

import os
import tempfile
from pysmi.builder import SmiBuilder
from pysmi.reader import FileReader

mib_content = """
DUMMY-MIB DEFINITIONS ::= BEGIN
    IMPORTS
        MODULE-IDENTITY, OBJECT-TYPE, enterprises
            FROM SNMPv2-SMI;

    dummyMIB MODULE-IDENTITY
        LAST-UPDATED "202310260000Z"
        ORGANIZATION "Example"
        CONTACT-INFO "example@example.com"
        DESCRIPTION
            "A dummy MIB for testing purposes."
        REVISION "202310260000Z"
        DESCRIPTION
            "Initial revision."
        ::= { enterprises 99999 }

    dummyObject OBJECT-TYPE
        SYNTAX      INTEGER
        MAX-ACCESS  read-only
        STATUS      current
        DESCRIPTION
            "A dummy object."
        ::= { dummyMIB 1 }

END
"""

with tempfile.TemporaryDirectory() as temp_dir:
    mib_path = os.path.join(temp_dir, "DUMMY-MIB.mib")
    # PySMI often needs standard MIBs; for simplicity, we mock an empty SNMPv2-SMI
    # In a real scenario, you'd point to a directory with actual standard MIBs
    snmpv2_smi_path = os.path.join(temp_dir, "SNMPv2-SMI.mib")
    with open(snmpv2_smi_path, "w") as f:
        f.write("SNMPv2-SMI DEFINITIONS ::= BEGIN END")

    with open(mib_path, "w") as f:
        f.write(mib_content)

    mibBuilder = SmiBuilder()
    mibBuilder.addMibSources(FileReader(temp_dir))

    try:
        mibBuilder.loadModules("DUMMY-MIB")
        # Retrieve the MIB node by name or OID to verify
        if mibBuilder.getMibNode(('DUMMY-MIB', 1)):
            print("Successfully loaded 'DUMMY-MIB' and found 'dummyObject'.")
        else:
            print("Failed to find 'dummyObject' within 'DUMMY-MIB'.")
    except Exception as e:
        print(f"Error loading MIB: {e}")

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