Package: ntc-templates-bsh
NTC TEMPLATES BSHRepository of TextFSM Templates for Network Devices, and Python wrapper for TextFSM's CliTable.TextFSMis a project built by Google that takes CLI string output and passes each line through a series of regular expressions until it finds a match. The regular expressions use named capture groups to build a text table out of the significant text. The names of the capture groups are used as column headers, and the captured values are stored as rows in the table.This project provides a large collection of TextFSM Templates (text parsers) for a variety of Networking Vendors. In addition to the templates, there is a function that will convert the CLI output into a CliTable object; the resulting text table is converted into a list of dictionaries mapping the column headers with each row in the table.As of v2.0.0, this project usesPoetryfor packaging and distribution. In order to use poetry, thetemplatesdirectory has been moved tontc_templates/templatesInstallation and UsageThe project can be installed using either Git + Poetry or PyPI.Git$gitclonegit@github.com:bsh-developers/ntc-templates-bsh.git
$# Optional steps to install ntc-templates as a python package$poetryinstall
$PyPI$pipinstallntc-templates-bsh
$Usage>>>fromntc_templates.parseimportparse_output>>>vlan_output=("VLAN Name                             Status    Ports\n""---- -------------------------------- --------- -------------------------------\n""1    default                          active    Gi0/1\n""10   Management                       active\n""50   VLan50                           active    Fa0/1, Fa0/2, Fa0/3, Fa0/4, Fa0/5,\n""                                                Fa0/6, Fa0/7, Fa0/8\n")>>>vlan_parsed=parse_output(platform="cisco_ios",command="show vlan",data=vlan_output)>>>vlan_parsed[{'vlan_id':'1','name':'default','status':'active','interfaces':['Gi0/1']},{'vlan_id':'10','name':'Management','status':'active','interfaces':[]},{'vlan_id':'50','name':'VLan50','status':'active','interfaces':['Fa0/1','Fa0/2','Fa0/3','Fa0/4','Fa0/5','Fa0/6','Fa0/7','Fa0/8']}]>>>Define Custom Templates DirectoryTo use a custom templates directory set the environmental variableNTC_TEMPLATES_DIR.Requirementsindexfile needs to be defined with standard structure.SeeEach custom template should be defined.To manaully set variable:exportNTC_TEMPLATES_DIR=/path/to/new/location/templatesTo set within your program:importosos.environ["NTC_TEMPLATES_DIR"]="/path/to/new/templates/location/templates"ContributingPull requests are welcomed and automatically built and tested through TravisCI.New TemplatesTo contribute new templates, each new pull request must include the following:TextFSM templateModified version of theindexfileTestsRaw version of text to be parsedYAML file containing the expected parsed dictionaryTextFSM TemplateTextFSM templates should be placed in the./templatesdirectory and should adhere to the following NTC-Templates style.
The TextFSM template name should be in the following format:NamingThe template should be named using:{{ vendor_os }}_{{ command_with_underscores }}.textfsmEx: cisco_ios_show_cdp_neighbors.textfsmNote: The vendor name must be valid from theos_choicestests, which is primarily based onNetmikolist of supported vendors. New vendors added should adhere tovendor_os.Ex: vmware_nsxValuesThe capture group names should be in UPPERCASE.An example of the proper format is shown below.Value TIME (\d+:\d+:\d+)
Value TIMEZONE (\S+)
Value DAYWEEK (\w+)
Value MONTH (\d+)
Value DAY (\d+)
Value YEAR (\d+)

Start
  ^${TIME}\s+${TIMEZONE}\s+${DAYWEEK}\s+${DAY}/${MONTH}/${YEAR} -> Record
  ^. -> ErrorStatesIf the raw output has a heading, theStartstate should match on the column headings and then transition to another state that will match the device's output table with the capture groups. This helps ensure the regex patterns for the capture groups are attempting to match the correct information, and allows templates to easily add additional States for tables that have different headings.
Example:Raw Output... omitted
Network Next Hop Metric LocPrf Weight Path
*> 111.111.111.111/32 112.112.112.112 4294967295 4294967295 65535 1000 1000 1000 iSample TemplateStart
# Checking for header
^\s*Network\s+Next(?:\s+|-)[Hh]op\s+Metric\s+LocPrf\s+Weight\s+Path\s*$$ -> BGPTable

BGPTable
 ... omittedEachstateshould end with^. -> Error. This helps to ensure we're accounting for every line within the raw output for the command. This doesn't mean we have to capture all the data as aValue, but we do have to account for it. In addition, it is also good to provide an expression to match blank lines,^\s*$$An example would be the following raw output:NAME: "3640 chassis", DESCR: "3640 chassis"
PID: , VID: 0xFF, SN: FF1045C5The template would be the following:Value NAME (.*)
Value DESCRIPTION (.*)

Start
  ^NAME:\s+"${NAME}",\s*DESCR:\s+"${DESCRIPTION}"
  ^PID:\s*,\s*VID:\s*\S+,\s*SN:\s*\S+
  ^\s*$$
  ^. -> ErrorTaking a look at the example template above, you notice that we're using\s* and\s+. These are the preferred way to match space characters, and should be used over the literal space character. For example,This\s+is\s+preferred\s*$$vsThis is not preferred$$\s* accounts for zero or more spaces (use when the output may or may not have a space between characters)\s+accounts for one or more spaces (use when output will have a space, but could have more than one space)Index FileThe Index file binds the templates to the commands being run. Special care has been taken on ordering, as there is potential for issues. e.g.show ip routepicking up forshow ip router vrf <vrf-name>. We have used a combination of ordering, as defined:OS in alphabetical orderTemplate name in length orderWhen length is the same, use alphabetical order of command nameKeep space between OS'sExample:Template, Hostname, Platform, Command

# same os, same length, used alphabetical order of command name
arista_eos_show_mlag.textfsm, .*, arista_eos, sh[[ow]] ml[[ag]]
arista_eos_show_vlan.textfsm, .*, arista_eos, sh[[ow]] vl[[an]]

# os in alphabetical order and space between cisco_asa and arista_eos
cisco_asa_dir.textfsm,  .*, cisco_asa, dir

# same os, template name length different and space between cisco_asa and cisco_ios
cisco_ios_show_capability_feature_routing.textfsm,  .*, cisco_ios, sh[[ow]] cap[[ability]] f[[eature]] r[[outing]]
cisco_ios_show_interface_transceiver.textfsm, .*, cisco_ios, sh[[ow]] int[[erface]] trans[[ceiver]]
cisco_ios_show_cdp_neighbors_detail.textfsm, .*, cisco_ios, sh[[ow]] c[[dp]] neig[[hbors]] det[[ail]]TestsTests will be located in./testswith the following hierarchy:./tests/{{ vendor_os }}/{{ command_name }}/The{{ command_name }}directory should include the.rawfile that includes the raw output of the command to be parsed, and the.ymlfile of the returned structured data.$lstests/cisco_ios/show_clock/
cisco_ios_show_clock.yml
cisco_ios_show_clock.raw
$Raw version of input textThe raw text file should containonlythe output of the CLI command to be parsed. It shouldnotcontain the CLI command itself.An example of the proper format is shown below:$cattests/cisco_ios/show_clock/cisco_ios_show_clock.raw
*18:57:38.347UTCMonOct192015$YAML file containing expected parsed dictionaryThe parsed file should match the data that is returned from theparse_outputfunction discussed in the beginning. Dictionary keys should be in lowercase.The parsed text file should be placed in a directory in the./testsdirectory with the same name as the template file but replace.textfsmfile extension with.yml. The raw text file and the parsed text file should be in the same directory.ex. ./tests/cisco_ios/show_clock/There are available helpers to create the parsed file in the correct format (SeeDevelopment Helper Scriptsbelow).An example of the proper format is shown below:$cat./tests/cisco_ios/show_clock/cisco_ios_show_clock.yml
---
parsed_sample:-time:"18:57:38.347"timezone:"UTC"dayweek:"Mon"month:"Oct"day:"19"year:"2015"$Multiplerawandparsedfiles are supported per directory, and are encouraged, as there are differences depending on version, length, etc. Additional test files and more real life data helps ensure backwards compatibility is maintained as each template is updated and merged into the repo.All YAML files must adhere to the YAML standards defined in the.yamllintfile in the root directory. Yamllint provides thorough documentation of their configuration settingshere.Development Helper ScriptsA cli utility is provided to assist with properly building the parsed files. This utility depends on some packages listed in the dev install requirements; seeInstall and Usagefor directions on installing the dev requirements. All arguments that can be passed to the script are mutually exclusive (i.e. you can only pass one argument). The file can be made executable with thechmod +x development_scripts.pycommand. The arguments are:-y: Takes the path to a YAML file and ensures that the file adheres to the .yamllint settings-yd: Takes a glob path to a directory or directories that will ensure all files ending in.ymladhere to the .yamllint settings-c: Takes the path to a.rawfile, and generates the parsed data and saves the results adjacent to the.rawfile following the defined standards in .yamllint.-cd: Takes a glob path to a directory or directories containing.rawfiles, and creates the appropriate parsed files in the appropriate directory.The-yand-ydarguments are designed to allow developers to generate the expected parsed file how they want, and ensure that the formatting adheres to the defined standard for this project.The-cand-cdarguments usentc_templates.parse.parse_output()to generate the parsed data; this means that you can use these arguments to auto-generate the test.ymlfile(s) for new templates; just be sure that the template's parsing behavior meets expectations. In order for the data to be parsed, the template must be placed inntc_templates/templates/and thentc_templates/templates/indexfile must be updated to correctly point to the template file(s).$./development_scripts.py-ydtests/cisco_ios/show_mac-address-table
tests/cisco_ios/show_mac-address-table/cisco_ios_show_mac-address-table2.yml
tests/cisco_ios/show_mac-address-table/cisco_ios_show_mac-address-table3.yml
tests/cisco_ios/show_mac-address-table/cisco_ios_show_mac-address-table5.yml
tests/cisco_ios/show_mac-address-table/cisco_ios_show_mac-address-table4.yml
tests/cisco_ios/show_mac-address-table/cisco_ios_show_mac-address-table.yml
$
$lstests/arista_eos/show_version/
arista_eos_show_version.raw
$
$./development_scripts.py-ctests/arista_eos/show_version/arista_eos_show_version.txt
$lstests/arista_eos/show_version/
arista_eos_show_version.rawarista_eos_show_version.yml
$Updating/Fixing Existing TemplatesWhen either fixing a bug within a template or adding additionalValuesto be captured, additional test files should be added to ensure backwards compatibility and that the new data is being parsed correctly.To add additional raw/parsed tests for a command:Navigate to./tests/{{ vendor_os }}/{{ command_name }}/Create new.rawand.ymlfiles within the directory, preferrably with a name identifying why the data is unique:Existing raw:./tests/cisco_ios/show_version/cisco_ios_show_version.rawNew raw:./tests/cisco_ios/show_version/cisco_ios_show_version_stack_platforms.rawExisting parsed:./tests/cisco_ios/show_version/cisco_ios_show_version.ymlNew parsed:./tests/cisco_ios/show_version/cisco_ios_show_version_stack_platforms.ymlTestingYou can test your changes locally within your Git branch before submitting a PR. If you do not havetoxalready installed, you can do that using pip or your systems package manager. Tox should be ran inside thentc-templatesroot directory. The tox file is configured to run against python3.6,python3.7, and python3.8, if none/some of those python versions are unavailabletoxwill skip them. The tox.ini file can be updated with an available Python version.$tox
GLOBsdist-make:/home/travis/build/networktocode/ntc-templates/setup.py
py36create:/home/travis/build/networktocode/ntc-templates/.tox/py36
py36inst:/home/travis/build/networktocode/ntc-templates/.tox/.tmp/package/1/ntc_templates-1.6.0.zip
py36installed:appdirs==1.4.4,attrs==20.3.0,black==20.8b1,click==7.1.2,dataclasses==0.8,future==0.18.2,importlib-metadata==3.7.0,iniconfig==1.1.1,mypy-extensions==0.4.3,ntc-templates==1.6.0,packaging==20.9,pathspec==0.8.1,pluggy==0.13.1,py==1.10.0,pyparsing==2.4.7,pytest==6.2.2,PyYAML==5.4.1,regex==2020.11.13,ruamel.yaml==0.16.12,ruamel.yaml.clib==0.2.2,six==1.15.0,textfsm==1.1.0,toml==0.10.2,typed-ast==1.4.2,typing-extensions==3.7.4.3,yamllint==1.26.0,zipp==3.4.0
py36run-test-pre:PYTHONHASHSEED='4147443973'py36run-test:commands[0]|black./--diff--check
Alldone!✨🍰✨9fileswouldbeleftunchanged.
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SKIPPED:py38:InterpreterNotFound:python3.8congratulations:)Thecommand"tox"exitedwith0.


Done.Yourbuildexitedwith0.
$QuestionsFor any questions or comments, please feel free to swing by thenetworktocode slack channel.Sign uphereCHANGELOGChangelog should be generated usinggithub_changelog_generatorFAQFrom an outsiders view, some design choices, requirements, and testing procedures can seem arbitrary. The following list of FAQ is intended to
help provide context and better guide users and contributors of ntc-templates.Why is there a requirement to useErrorin every template?Ensuring that the textfsm template can account for every line is the only method to ensure that data was not accidentally missed. Take the following example. Initially we account for status to be:Value STATUS (up|down)Given the result of:Interface                      Status         Protocol Description
Gi0/0/1                        admin down     down
Gi0/0/2                        up             up       ISP Connection
Gi0/0/3                        down           downThe output would miss the G0/0/1 interface, since theSTATUSofadmin downnot known. If this was a low percentage use case, it can go
undetected, and result in incorrect information being returned. Instead, by ensuring that we fail fast, anErroris raised and hopefully
GitHub Issue is put in.Then why isn'tErrorused in all templates?Initially the controls were not as strong, so many templates were put in until issues like the previous became an issue.Does the project support requests for additional templates or additional data in an existing template?We are no longer considering additional template requests at this time. The project has existed for over 5 years (initially within ntc-ansible)
and nearly 200 template at this point any additional requests are essentially edge use cases. Meaning, for five years of usage, no one else
has asked for this feature. There is a limited maintainers who primarily use their free time to maintain the project.Are you open to adding maintainers to the project?Yes, we would consider giving a proven member of the project and community maintainer rights. Please inquiry emailinginfo@networktocode.com.I simply want to add my template to the project, I do not want to add all of these tests and controls, can I just do so?Short answer no, from an outsiders point of view the contributor requirements may seem overly complex, however features added by engineers
rarely come back to support them. The burden of support is on the maintainers and a certain level of quality assurance is required for that to
happen. That includes updating the index file appropriately and adding proper raw and expected value files.Why don't you grab all of the data in the template?There is no intention for ntc-templates to become feature complete, some of the data is less interesting, or can be better understood from
other commands. This is actually an area where the project chose to be loose, as we do not want to over-burden the contributor. If you feel
that the additional data should be added, you are welcome to add the feature, but it would not be considered a bug, and thus not supported by
the maintainers of the this project.Why does the index order matter?The "greediness" of the template match ensures that there longest matches first. For example, ifshow ip ospfwas aboveshow ip ospf database, theshow ip ospftemplate would be used in both cases. The additional steps are because of general programmatic hygiene.Will you accept my template if I create it?In most cases, yes. However, there are a few edge cases. For example if requesting to add ashow cdp neighborswhen there is already ashow cdp neighbors detailstemplate created. That is additional complexity added to the project with little value.Why was my issue closed?The most likely reasons are:Did not follow the Issue creation template.Did not provide the data required to act upon the request.A prolonged time with no response.What is meant that this is a parsing project, not a data modeling project?The project intends to parse, meaning post processing is assumed in order to normalize the data. This project does not intend to solve that
problem set. This is often noted in keys being different between the same command on multiple OS's. This was not intentional as at first there was not strict enforcement. That being said, there is no intention to retrofit this use case for the above stated reasons. This use case is
best handled in post processing.I have never submitted a Pull Request before, how do I do so?This is outside the scope of this project, but thisvideoshould provide the instructions on
how to do so.Does this work on windows?Based on thisPRit should, however this is not a supported option. We are willing
to take in qualified Pull Requests to have the feature, but have no intention of actively supporting.Can you provide general guidance?This is best handled via real time communication. Feel free to join our slack community (sign up information above) and reach out on the #networktocode channel. Please be aware of timezones, downtimes, and help is performed based on goodwill and timing, and not guaranteed.Known IssuesCannot import name clitable from textfsmntc-templatesdepends ontextfsm, which hasn't published a source distribution to pypi in a while. Seehttps://github.com/google/textfsm/issues/65.This means that for users with a build chain that depends on source distributions only (i.e. no wheels), ntc-templates appears to have a bug:File "/usr/local/Cellar/foo/version/libexec/lib/python3.7/site-packages/ntc_templates/parse.py", line 3, in <module>
    from textfsm import clitable
ImportError: cannot import name 'clitable' from 'textfsm'What's actually happening here is that textfsm provides a source distribution only up to version 0.4.1 (2018-04-09) but the ntc-templates code relies on the interface from version 1.1.0 (2019-07-24) which is only available as a wheel. So the way for users to fix this problem if they encounter it is to install textfsm 1.1.0.pip install textfsm==1.1.0This was taken fromhttps://github.com/networktocode/ntc-templates/issues/731