exhuma/puresnmp

Pure Python SNMPv2 Library

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TL;DR

Jump right in with the cookbook

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Quick Info

What

A pure Python implementation for Python 3.6+ of SNMP without any external dependencies (neither MIBs or libsnmp).

Why

SNMP in itself is simple and well defined. A bit convoluted, but simple. MIB parsing however complicates the code-base and is technically not required. They add typing information and variables and give names to OIDs. All existing libraries have a direct or indirect dependency on libsnmp. With all the advantages and disadvantages.

The aim of this project is to focus on SNMP in itself and provide a very simple API. Instead of implementing ASN.1 parsing, the SNMP related ASN.1 and information is hard-coded (keeping in mind that all that's hard-coded is well defined).

It is of course possible to wrap this package in another package adding MIB parsing and processing. This is, and will be however out of the scope of this project!

When

First commit: Sat Jul 23 12:01:05 2016 +0200

Who

Michel Albert

Installation

pip install puresnmp

Package Version Numbers

As an important side-note, you might want to know that this project follows Semantic Versioning.

Examples

See the cookbook.

Development & Maintenance

The easiest way to get started it to use the provided "development container" in the .devcontainer folder. When using VS-Code with the Remote Development extension it will be picked up automatically when opening the project. If not, open the command-console and select Remote-Containers: Rebuild Container to get started.

Type ./env/bin/pytest to ensure that everything is set up properly. It should run and pass all unit-tests.

This will provide a container with all required dependencies for development. Including a tiny SNMP daemon on hostname snmpd which can be used to play around with.

puresnmp's Issues

Simplify the "external" API.

Currently the top-level module contains a couple of duplicate functions, for example walk and multiwalk or get and multiget.

This can lead to confusion. It was meant to keep the arguments simple for simple requests but introduces too much inconsistency. The "multi" functions should be kept. This way all functions will accept a lit of OIDs making the overall API calls more consistent.

string length calculation confusion

puresnmp.x690.types.OctetString.init() converts value to ascii, but then calculates length on the original possibly unicode input value.

now, since it's converting to ascii, any multi-byte character would just throw a unicode error anyway, but it feels wrong to be calculating the length on the wrong value.

Please feel free to just close this as me being pedantic, but the I posted this is because I was already typing this issue report before I realized it wasn't a bug and it could cause others confusion in the future.

OID '0' raises an IndexError

When receiving the byte value 06 00 the library raises an IndexError.

It should however return the following OID:

ObjectIdentifier(0)

Implement Bulk Requests

As the title says.

Large numeric values are not properly encoded

As reported to me via e-mail:

Hi Albert,

looks like the encode_length() function in x690/util.py is broken. It produces little endian byte ordering for the long definite form instead of big endian.
Inserting

output.reverse()

before prefixing the info length seems to do the job. The decoding is correct, though.

Regards,
harti

Some integers are encoded wrong

As reported by harti:

I observed this by chance when encoding 32768. The current code yields 0x8000. Since integers are signed (also the unsigned types!) this actually is a -0. The correct encoding is 0x008000. The following code in Integer seems to fix this, but it deserves probably more testing for the edge cases:

def __bytes__(self):
    if self.value == 0:
        octets = [0]
    else:
        # Split long integers into multiple octets.
        remainder = self.value
        octets = []
       
        while True:
            octets.append(remainder & 0b11111111)
            if remainder == 0 or remainder == -1:
                break
            remainder = remainder >> 8
        if remainder == 0 and octets[-1] == 0b10000000:
            octets.append(0)
        octets.reverse()
       
        # remove leading octet if there is a string of 9 zeros or ones
        while len(octets) > 1 and (octets[0] == 0 and octets[1] & 0b10000000 == 0) or \
            (octets[0] == 0b11111111 and octets[1] & 0b10000000 != 0):
            del octets[0]
           
    tinfo = TypeInfo(self.TYPECLASS, TypeInfo.PRIMITIVE, self.TAG)
    return bytes(tinfo) + bytes([len(octets)]) + bytes(octets)

Review PEP8 compliance & Write/Update Contribution Guide

I've introduced some PEP8 errors (Identified in #32 which should be fixed. Additionally, to avoid confusion in future PRs, the contribution guide should contain a note about which linter is used.

SNMPv1 support

Tried to use puresnmp against a SNMPv1 device, and was unsuccessful. After digging into the docs some more, it seems it only supports SNMPv2c currently, with v3 support planned.

However, there are still a significant number of SNMPv1 devices "out in the wild". Would you consider supporting SNMPv1, or do you consider that to be out of scope for this project?

I'd be willing to write up an implementation when I get some time.

Provide a non-leaky API

Currently, the package provides a "leaky abstraction" in the sense that calls to the main entry-point functions return data-types which are internal to puresnmp (most notably ObjectIdentifier).

The returned data-types should always be pure Python types.

Sometimes the "raw" data-types may provide useful functionalities, and as such a second entry-point should be provided to return the values unmodified. This would make it explicit to the end-user what kind of types are returned.

full OID walk doesn't yield until walk is complete

Is there a reason why doing a full walk on a device, it doesn't start yielding until after it has accumulated all the data from the device? Would it break anything to modify the logic to start yielding in multiwalk's "while unfinished_oids" block?

Implement ObjectIdentifier.parentof and ObjectIdentifier.childof

These are functions available in another library I wrote years back and some projects depend on this functionality.

Currently __contains__ exist which may cover this. This ticket exists so that I don't forget to verify this before releasing 1.3.

Old implementation (incompatible when used verbatim):

def parentof(self, other):
    """
    Returns ``True`` if *other* is a direct parent of this OID:

        >>> ObjectIdentifier('1.2').parentof(ObjectIdentifier('1.2.3'))
        True
        >>> ObjectIdentifier('1.3').parentof(ObjectIdentifier('1.2.3'))
        False
    """
    # pylint: disable=protected-access
    if not isinstance(other, ObjectIdentifier):
        other = ObjectIdentifier(other)
    if self == other:
        return True
    if len(self._nodes) > len(other._nodes):
        return False
    common_head = other._nodes[:len(self._nodes)]
    return common_head == self._nodes

def childof(self, other):
    """
    Returns ``True`` if *other* is a direct child of this OID:

        >>> ObjectIdentifier('1.2.3').childof(ObjectIdentifier('1.2'))
        True
        >>> ObjectIdentifier('1.1.3').childof(ObjectIdentifier('1.2'))
        False
    """
    # pylint: disable=protected-access
    if not isinstance(other, ObjectIdentifier):
        other = ObjectIdentifier(other)
    if self == other:
        return False
    if len(self._nodes) < len(other._nodes):
        return False
    common_head = self._nodes[:len(other._nodes)]
    return common_head == other._nodes

Add information about types to the docs.

The set command requires typing information for variables. However, there is no reference of the available types available in the docs.

Add the necessary information to the docs!

Make the ObjectIdentifier type sortable

Typo in "contributing" doc.

really no my domain of expertise

should be

really not my domain of expertise

Verify consistency with RFC3416

RFC 3416 contains more details about variable types and their inheritance than I originally found. Additionally it's from a more recent RFC which was not linked in the one I used originally.

Compare the existing codebase with RFC3416 and see if there are no errors.

Fix License info in setup.py

The license in setup.py should be MIT, not BSD,

Publish on pypi

Publish official release on pypi as soon as the remaining issues for Release 1.0 are implemented.

Fix assymetry between converting a PDU to bytes and converting bytes to a PDU.

When using pop_tlv to convert a bytes object to a bytes object into a PDU object, the result is different than what you might expect.

• Instantiating a PDU class takes pure Python integer objects as initialisor arguments.
• When converting a PDU using pop_tlv these values are represented as puresnmp Integer instance.

This has been observed with the error_index and error_status fields.

Querying for a non-existent OID on a target machine causes a non-handled exception to occur

When querying for a non-existent OID on a target machine, it causes an exception which is not handled properly by puresnmp.

Traceback (most recent call last):
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/pdu.py", line 184, in decode
    return super().decode(data)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/pdu.py", line 89, in decode
    values, data = pop_tlv(data)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/x690/types.py", line 89, in pop_tlv
    value = cls.from_bytes(chunk)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/x690/types.py", line 134, in from_bytes
    return cls.decode(data)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/x690/types.py", line 319, in decode
    value, data = pop_tlv(data)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/x690/types.py", line 89, in pop_tlv
    value = cls.from_bytes(chunk)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/x690/types.py", line 134, in from_bytes
    return cls.decode(data)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/x690/types.py", line 319, in decode
    value, data = pop_tlv(data)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/x690/types.py", line 89, in pop_tlv
    value = cls.from_bytes(chunk)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/x690/types.py", line 134, in from_bytes
    return cls.decode(data)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/pdu.py", line 80, in decode
    raise EmptyMessage('No data to decode!')
puresnmp.exc.EmptyMessage: No data to decode!

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "main_test.py", line 306, in <module>
    analyzer_list, importer_list, import_analyzer_mapping, snmp_statistics = first_run()
  File "main_test.py", line 265, in first_run
    effected_importers = snmp_statistics.gen_effected_importers(import_analyzer_mapping.get_mapping())
  File "main_test.py", line 230, in gen_effected_importers
    backedup_analyzers = self._analyzer_que_lookup()
  File "main_test.py", line 216, in _analyzer_que_lookup
    result = get(ip_address, self.community, snmp_oid)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/__init__.py", line 60, in get
    return multiget(ip, community, [oid], port)[0]
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/__init__.py", line 84, in multiget
    raw_response = Sequence.from_bytes(response)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/x690/types.py", line 134, in from_bytes
    return cls.decode(data)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/x690/types.py", line 319, in decode
    value, data = pop_tlv(data)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/x690/types.py", line 89, in pop_tlv
    value = cls.from_bytes(chunk)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/x690/types.py", line 134, in from_bytes
    return cls.decode(data)
  File "/usr/lib/python3.5/site-packages/puresnmp-1.1.5-py3.5.egg/puresnmp/pdu.py", line 186, in decode
    raise NoSuchOID('Nothing found at the given OID (%s)' % exc)
puresnmp.exc.NoSuchOID: Nothing found at the given OID (No data to decode!)

Documentation is not properly generated on readthedocs.org

The documentation process ends in success, but the docs are incomplete. The build log contains the following two interesting tracebacks:

/home/docs/checkouts/readthedocs.org/user_builds/puresnmp/checkouts/stable/docs/developer_guide/api/puresnmp.rst:25: WARNING: autodoc: failed to import module 'puresnmp'; the following exception was raised:
Traceback (most recent call last):
  File "/home/docs/checkouts/readthedocs.org/user_builds/puresnmp/envs/stable/lib/python3.4/site-packages/sphinx/ext/autodoc.py", line 385, in import_object
    __import__(self.modname)
  File "/home/docs/checkouts/readthedocs.org/user_builds/puresnmp/envs/stable/lib/python3.4/site-packages/puresnmp-1.1.3.post2-py3.4.egg/puresnmp/__init__.py", line 39, in <module>
    'version.txt').decode('ascii').strip()
  File "/home/docs/checkouts/readthedocs.org/user_builds/puresnmp/envs/stable/lib/python3.4/site-packages/pkg_resources/__init__.py", line 1162, in resource_string
    self, resource_name
  File "/home/docs/checkouts/readthedocs.org/user_builds/puresnmp/envs/stable/lib/python3.4/site-packages/pkg_resources/__init__.py", line 1603, in get_resource_string
    return self._get(self._fn(self.module_path, resource_name))
  File "/home/docs/checkouts/readthedocs.org/user_builds/puresnmp/envs/stable/lib/python3.4/site-packages/pkg_resources/__init__.py", line 1726, in _get
    with open(path, 'rb') as stream:
FileNotFoundError: [Errno 2] No such file or directory: '/home/docs/checkouts/readthedocs.org/user_builds/puresnmp/envs/stable/lib/python3.4/site-packages/puresnmp-1.1.3.post2-py3.4.egg/puresnmp/version.txt'

/home/docs/checkouts/readthedocs.org/user_builds/puresnmp/checkouts/stable/docs/developer_guide/api/puresnmp.const.rst:4: WARNING: autodoc: failed to import module 'puresnmp.const'; the following exception was raised:
Traceback (most recent call last):
  File "/home/docs/checkouts/readthedocs.org/user_builds/puresnmp/envs/stable/lib/python3.4/site-packages/sphinx/ext/autodoc.py", line 385, in import_object
    __import__(self.modname)
  File "/home/docs/checkouts/readthedocs.org/user_builds/puresnmp/envs/stable/lib/python3.4/site-packages/puresnmp-1.1.3.post2-py3.4.egg/puresnmp/__init__.py", line 18, in <module>
    from . import types  # NOQA (must be here for type detection)
ImportError: cannot import name 'types'

"bulkwalk" does not work properly

In the current release (1.1.1), bulkwalk raises the following error on OID 1.3.6.1.2.1.2.1:

Traceback (most recent call last):
  File "my__.tester.py", line 90, in <module>
    test_if_oper_stat()
  File "my__.tester.py", line 85, in test_if_oper_stat
    for row in iftable:
  File "/home/users/michel/work/pynet/env/lib/python3.4/site-packages/puresnmp/__init__.py", line 475, in bulkwalk
    for oid, value in result:
  File "/home/users/michel/work/pynet/env/lib/python3.4/site-packages/puresnmp/__init__.py", line 225, in multiwalk
    unfinished_oids = get_unfinished_walk_oids(varbinds, requested_oids)
  File "/home/users/michel/work/pynet/env/lib/python3.4/site-packages/puresnmp/__init__.py", line 201, in get_unfinished_walk_oids
    for k, v in results.items()}
  File "/home/users/michel/work/pynet/env/lib/python3.4/site-packages/puresnmp/__init__.py", line 201, in <dictcomp>
    for k, v in results.items()}
IndexError: list index out of range

IpAddress is encoded with the wrong tag

As reported by harti:

The type inherits from OctetString and the OctetString encoder has the type hardcoded. Using the following in OctetString fixes the issue:

def __bytes__(self):
    tinfo = TypeInfo(self.TYPECLASS, TypeInfo.PRIMITIVE, self.TAG)
    return bytes(tinfo) + self.length + self.value

Review type-hierarchy of NonASN1Type &

Creating a separate issue from something identified in PR #32:

By @remdragon:

Actually, I did the alias wrong. I need to create it as a subclass of
UnknownType so that repr() will output the correct value. Also, I think the
subclass will be necessary in order to flag it as deprecated anyway. Please
give me a chance to fix that.

Inconsistency of return types of "walk" and "bulkwalk"

"walk" returns pythonized values whereas "bulkwalk" returns raw values.

"bulkwalk" should also return pythonized values.

Provide access to the lower-level SNMP variable types.

Currently (by design) the SNMP types are converted to Python types on the library boundaries.

This make day-to-day work easy and straight-forward. But information is lost which may be helpful in some cases and should be made accessible.

I'm planning to refactor the existing functions into "low-level" functions which will also be intended to be used by end-users of the library. Then, in order to retain the "easy" interface, new functions will be introduced which depend on the older, lower-level functions and to the existing type conversions.

Allow modifying the socket chunk-size

Currently the chunk-size for socket reading is hardcoded to 4096 bytes. This value could be made configurable for the end-user. This is kind of related to #45 as it may reduce the chance of running into #45. However, fixing #45 has priority!

This is also related to #1 as it is another configuration value for the network behaviour.

Currently the timeout value is exposed by most top-level functions. To guarantee backwards-compatibility a new argument chunk_size should be introduced.

For the next major release, this would make more sense in the creation of an SNMP-Client instance (see also #3)

Implement "tabular" data without MIB information

It is possible to get something very similar to tables, even without MIBs. It is doable to return a list of dicts, where each list item represents a row in the table, and the dict contains the colums where the key equals the column ID from the OID.

Why not a list of lists?

Some manufaturers have "sparse" tables. This introduces an ambiguity when using lists as columns: If an index is set to None, does that mean the element was missing, or does it mean it was explicitly reported as Null.

Using dicts removes this ambiguity.

Add a brief explanation of ASN.1 and MIB to the docs.

For SNMP beginners, these terms are unknown. A simple 1-2 sentence entry in the glossary would help. No need to go into detail. Just one sentence & link to an external (authoritative) document.

pyinstaller packaging

Ran into an issue when packaging up puresnmp in a project with pyinstaller.

The program wouldn't run because version.txt didn't get included.

Can I remove dependency on that file or prevent the script from crashing if it can't be found?

Implement __len__ for ObjectIdentifier

Running len(ObjectIdentifier.from_string('1.2.3.4')) should return 4

Check whether it makes sense to make use of the namedtuple used in decode_length

The decode_length function returns a namedtuple since one of the latest commits. This opens up the possibility to access its elements via name instead of indices. This makes code more readable. I don't remember if the return value is always used via variable unpacking, or if the indices are used somewhere.

In case the indices are used, they should be replaced with the new namedtuple attributes.

fact finding for asyncio support

I'm interested in learning what it would take to bring asyncio support to puresnmp.

Endless loop for some devices caused by regression in 1.3.2

The endless loop which was fixed in 1.3.1 was reintroduced in 1.3.2

transport.send missing timeout argument in 1.5.1

Hello, thanks for this excellent approach to handle SNMP.
After update from from 1.4.1 to 1.5.1 the api stopped to work because of missing keyword argument:
in puresnmp/transport.py:

def send(self, ip, port, packet):  # pragma: no cover
    # type: ( str, int, bytes ) -> bytes

but the call remain using timeout:
in puresnmp/api/raw.py

response = transport.send(ip, port, to_bytes(packet), timeout=timeout)

bulkwalk incorrectly handles EndOfMibView

I'm retrieving a small table near the end of the MIB (followed by 5 scalars). The response contains the table, the 5 scalars and EndOfMibView. This leads to bulkwalk raising an exception.

Actually it should return the retrieved values and the EndOfMibView indication so that the application can read values near the end of the MIB and also figure out that it has hit the end of the MIB.

I tried to figure out where exactly the problem happens but I got lost...

This is the end of the response message:

_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00
.1.3.6.1.6.3.1.1.6.1.0=128024585
.1.3.6.1.6.3.10.2.1.1.0=80_00_08_be_80_33_37_34_30_37_37_33_33_35_35
.1.3.6.1.6.3.10.2.1.2.0=1
.1.3.6.1.6.3.10.2.1.3.0=1656
.1.3.6.1.6.3.10.2.1.4.0=1500
.1.3.6.1.6.3.10.2.1.4.0=[endOfMibView] } }

get and other methods does not support using host name instead of ip

In my test environment IP's might change so I prefer to use host names. Is there a way to get this working without extra layer on my side?

At the moment I am getting:
ValueError: 'server_name.mydomain.local' does not appear to be an IPv4 or IPv6 address

Duplicated type check

puresnmp/puresnmp/api/raw.py

Line 461 in d8ec41e

if not isinstance(oids, list):

This conditional is repeated three lines lower.

Support the IpAddress type

The type with tag 0x40 should be detected as IpAddress. This should be exposed as instance from the ipaddress module on the high-level border of the puresnmp module.

Response packets larger than 4096 bytes are not handled properly.

When a response is larger than 4096 bytes, the following error is raised:

[...]
  File "/home/users/malbert/work/private/puresnmp/puresnmp/api/pythonic.py", line 183, in bulkwalk
    for oid, value in result:
  File "/home/users/malbert/work/private/puresnmp/puresnmp/api/pythonic.py", line 117, in multiwalk
    for oid, value in raw_output:
  File "/home/users/malbert/work/private/puresnmp/puresnmp/api/raw.py", line 203, in multiwalk
    timeout)
  File "/home/users/malbert/work/private/puresnmp/puresnmp/api/raw.py", line 408, in fetcher
    port=port, timeout=timeout)
  File "/home/users/malbert/work/private/puresnmp/puresnmp/api/raw.py", line 367, in bulkget
    raw_response = Sequence.from_bytes(response)
  File "/home/users/malbert/work/private/puresnmp/puresnmp/x690/types.py", line 153, in from_bytes
    cls, expected_length, len(data)))
ValueError: Corrupt packet: Unexpected length for <class 'puresnmp.x690.types.Sequence'> Expected 6501 (0x1965) but got 4092 (0xffc)

This is due to the way sock.recv is used in puresnmp.transport. It only fetches one chunk and does not continue reading after that.

Prevent endless loops cause by incorrect SNMP implementations

I've run into a bug in a network device which does not behave correctly on GetNext requests. Instead of returning the next OID it will return the same OID as the one requested on some rare occasions.

This causes endless loops on walk and bulkwalk (and thus table requests as well). A check should be introduced that verifies that the OID received by getnext is different from the one passed in. A more precise check would be to check if the returned OID is "larger" than the one passed in.

These checks may have a considerable performance impact on larger walk operations, primarily the check if the OID is increasing. They should therefore be made optional.

Support multiple varbinds in GET, GETNEXT and SET

The PDUs support multiple OIDs in one packet and should be supported.

Usage of "recv_all" makes no sense for UDP

Data can only be read exactly once from a UDP socket. All bytes which don't fit into the buffer are discarded.

Currently the module puresnmp.transport contains an implementation to repeatedly read data from the socket if the buffer is too small. This makes only sense for TCP and causes a timeout exception for UDP if the package is too large.

puresnmp should simply read once. If any data is discarded (i.e. if the buffer-size is too small), it will result in a truncated package which will trigger a "corrupt packet" error. This should make it easier to pinpoint the error.

Additionally, the corrupt-package error message could include a hint to the buffer size.

Make the `__repr__` of IpAddress instances more human-readable.

Currently the representation of the IpAddress type contains a byte-string. Converting the byte-string to an ip-address would make log output much more readable.

The following line would break the API with the superclass Type:

IpAddress('192.168.1.1')

becuase the superclass requires a bytes object as argument. The following would keep a consistent API but would make output quite long:

IpAddress.from_string('192.168.1.1')

Alternatively a non-executable form may be used:

<IpAddress 192.168.1.1>

Merge "multi" methods with "simple" methods.

The code in the simple methods like puresnmp.get predate the functions in puresnmp.multiget. Other, similar cases exist for walk and set.

There's quite some code-duplication. It is possible to keep the "multi" functions, and make the "simple" functions thin wrappers around those "multi" methods. This should remove the duplication and still keep both versions available.

Why keep both, and why not only keep the "multi" variants?

One main aim of the library is to keep the API as simple as possible. Having both versions makes:

• The difference between both calls explicit
• the API of the "simple" methods as simple as possible.

Initial Update

The bot created this issue to inform you that pyup.io has been set up on this repo.
Once you have closed it, the bot will open pull requests for updates as soon as they are available.

Add a cookbook entry for bulk requests

As the title says.

Generated docs (API & Type Tree) is not published on readthedocs

Some parts of the documentation is auto-generated via the fabric script.

RTD does not run the fabric script and thus does not include the generated documentation. This needs to be fixed!

Process the "error-index" value in error-responses.

Error responses contain variable bindings. In case of an error, the error-index is set to the index of the failed variable binding. This detail is currently not included in error messages but should be.

Ensure that TimeTicks, Counter32 and Gauge32 work

I seem to remember to have implemented the TimeTick, Counter32 and Gauge32 types. But they are not properly detected!

Timeout takes too long if community string is incorrect

I've noticed when using an incorrect community string, a sent message never times out while waiting for a response (or it takes longer that I was willing to wait). Perhaps a sock.settimeout(2) or something similar should be added in the puresnmp.transport.send() function. It could also be made adjustable by adding a default argument in function calls.