This text provides several use-case of the yanglint(1) interactive mode. For basic information about the yanglint(1) usage, please see the man page.
The examples are supposed to be went through one by one. Some of the examples suppose the specific schemas loaded in some of the previous example is still loaded. If an addition work is need, the preparation part in the example provides information what to do.
To show all available command of the yanglint(1), use the help command:
> help Available commands: help Display commands description add Add a new model print Print model data Load, validate and optionally print instance data xpath Get data nodes satisfying an XPath expression list List all the loaded models feature Print/enable/disable all/specific features of models searchpath Set the search path for models clear Clear the context - remove all the loaded models verb Change verbosity quit Quit the program ? Display commands description exit Quit the program
To show the information about the specific command, use the help command in combination with the command name you are interested in:
> help searchpath searchpath <model-dir-path>
The input files referred in this document are available together with this document.
Let's have two data models module1.yang and module1b.yang. They differ in the module name but their namespaces are the same.
Preparation:
> clear > add module1.yang > list
Output:
List of the loaded models (mod-set-id 5):
ietf-inet-types@2013-07-15
ietf-yang-types@2013-07-15
ietf-yang-library@2015-07-03
module1
Command and its output:
> add module1b.yang
libyang[0]: Two different modules ("module1" and "module1b") have the same namespace "urn:yanglint:module".
libyang[0]: Module "module1b" parsing failed.
YANG/YIN syntax
module2.yin contains a syntax error. There is a bad syntax of the type statement in YIN file.
<type value="string"/>
instead of
<type name="string"/>
Preparation:
> clear
Command and its output:
> add module2.yin libyang[0]: Missing argument "name" to keyword "type". libyang[0]: Module "module1" parsing failed.
Similarly, there is a typo in module2.yang.
XPath errors
libyang and yanglint(1) is able to detect also errors in XPath expressions. In module3.yang the must expression refers to the node which does not exists.
Preparation:
> clear
Command and its output:
> add module3.yang libyang[0]: Schema node "a" not found (../c/a). libyang[0]: Path is related to the previous error message. (path: /module3:m) libyang[0]: Module "module3" parsing failed.
Note that libyang does not provide line numbers of the error. Instead it tries to print the path to the related node. in some cases (as this one) it is not able to print the path immediately so the path (to the node m which refers node which does not exist) is printed in the second message.
Preparation:
> clear > add ietf-netconf-acm.yang
Unknown data
By default, yanglint ignores unknown data and no error is printed (you can compare real content of the datastore.xml file and what yanglint prints in the following command if you add -f xml option).
Command and its output:
> data -t config datastore.xml
We use option -t to specify type of the data in datastore.xml. By the config value we declare that the input file contains all the configuration data (with at least all the mandatory nodes as required by the loaded schemas), but without the status data. More examples of different data types will follow.
To handle unknown data as error, use strict mode (-s option).
Command and its output:
> data -t config -s datastore.xml libyang[0]: Unknown element "interfaces". (path: /) Failed to parse data.
Note that in case of working with complete datastore including the status data (no -t option is specified), yanglint(1) has to add status data from its internal ietf-yang-library module. Using the -s option in this case forces validation in time of parsing the input file so it is expected to include also the mandatory status data from the ietf-yang-library module.
Multiple top-level elements in a single document
As a feature and in conflict with the XML definition, yanglint(1) (and libyang) is able to read XML files with multiple top-level elements. Such documents are not well-formed according to the XML spec, but it fits to how the YANG interconnects data trees (defined as top-level elements of a single schema or by multiple schemas).
Preparation:
Command and its output:
> clear > add ietf-netconf-acm.yang > add ietf-interfaces.yang > add ietf-ip.yang > add iana-if-type.yang
Command and its output:
> data -t config -s datastore.xml
Different data content types
Since NETCONF requires the data described by YANG to be used in different situations (e.g. as , result of the with status data included or as a result of the without the status data and possibly filtered, so without specified subtrees), it must be possible to specify which kind of data is going to be parsed. In yanglint(1), this is done via -t option. The list of supported modes can be displayed by the -h option given to the data command. In general, the auto value lets the yanglint(1) to recognize the data type automatically by the additional top-level elements added to the parsed data. This is the same way as pyang(1) uses. Note, that the automatic data type recognition is available only for the XML input.
Malformed XML data
Command and its output:
> data -t edit config-missing-key.xml libyang[0]: Invalid (mixed names) opening (nam) and closing (name) element tags. (path: /nacm/groups/group/nam) Failed to parse data.
State information in edit-config XML
Command and its output:
> data -t edit config-unknown-element.xml libyang[0]: Unknown element "denied-operations". (path: /ietf-netconf-acm:nacm/denied-operations) Failed to parse data.
Missing required element in NETCONF data
Command and its output:
> data data-missing-key.xml libyang[0]: Missing required element "name" in "rule". (path: /ietf-netconf-acm:nacm/rule-list[name='almighty']/rule) Failed to parse data.
Malformed XML
Command and its output:
> data data-malformed-xml.xml libyang[0]: Invalid (mixed names) opening (nam) and closing (rule) element tags. (path: /nacm/rule-list/rule/nam) Failed to parse data.
Command and its output:
> data data-malformed-xml2.xml libyang[0]: Invalid (mixed names) opening (module-name) and closing (name) element tags. (path: /nacm/rule-list/rule/name/module-name) Failed to parse data.
Bad value
Command and its output:
> data data-out-of-range-value.xml libyang[0]: Invalid value "-1" in "denied-operations" element. (path: /ietf-netconf-acm:nacm/denied-operations) Failed to parse data.
Preparation:
> clear > add ietf-netconf-acm-when.yang
When condition is not satisfied since denied-operation = 0
Command and its output:
> data data-acm.xml
The command succeeds. It is because yanglint(1) (via libyang) performs autodeletion - the not satisfied when condition in denied-data-writes causes its automatic (silent) deletion.
Preparation:
> clear > add ietf-netconf-acm.yang
Print a pyang-style tree
Command and its output:
> print ietf-netconf-acm
module: ietf-netconf-acm
+--rw nacm
+--rw enable-nacm? boolean <true>
+--rw read-default? action-type <permit>
+--rw write-default? action-type <deny>
+--rw exec-default? action-type <permit>
+--rw enable-external-groups? boolean <true>
+--ro denied-operations ietf-yang-types:zero-based-counter32
+--ro denied-data-writes ietf-yang-types:zero-based-counter32
+--ro denied-notifications ietf-yang-types:zero-based-counter32
+--rw groups
| +--rw group* [name]
| +--rw name group-name-type
| +--rw user-name* user-name-type
+--rw rule-list* [name]
+--rw name string
+--rw group* union
+--rw rule* [name]
+--rw name string
+--rw module-name? union <*>
+--rw (rule-type)?
| +--:(protocol-operation)
| | +--rw rpc-name? union
| +--:(notification)
| | +--rw notification-name? union
| +--:(data-node)
| +--rw path node-instance-identifier
+--rw access-operations? union <*>
+--rw action action-type
+--rw comment? string
>
Obtain information about model
Command and its output:
> print -f info ietf-netconf-acm
Module: ietf-netconf-acm
Namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-acm
Prefix: nacm
Desc: NETCONF Access Control Model.
Copyright (c) 2012 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD
License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC 6536; see
the RFC itself for full legal notices.
Reference:
Org: IETF NETCONF (Network Configuration) Working Group
Contact: WG Web: <http://tools.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
WG Chair: Mehmet Ersue
<mailto:mehmet.ersue@nsn.com>
WG Chair: Bert Wijnen
<mailto:bertietf@bwijnen.net>
Editor: Andy Bierman
<mailto:andy@yumaworks.com>
Editor: Martin Bjorklund
<mailto:mbj@tail-f.com>
YANG ver: 1.0
Deviated: no
Implement: yes
URI:
Revisions: 2012-02-22
Includes:
Imports: yang:ietf-yang-types
Typedefs: user-name-type
matchall-string-type
access-operations-type
group-name-type
action-type
node-instance-identifier
Idents:
Features:
Augments:
Deviation:
Data: container "nacm"
Print information about specific model part
Command and its output:
> print -f info -t /ietf-netconf-acm:nacm/ietf-netconf-acm:enable-nacm ietf-netconf-ac
Leaf: enable-nacm
Module: ietf-netconf-acm
Desc: Enables or disables all NETCONF access control
enforcement. If 'true', then enforcement
is enabled. If 'false', then enforcement
is disabled.
Reference:
Config: read-write
Status: current
Mandatory: no
Type: boolean
Units:
Default: true
If-feats:
When:
Must:
NACM: default-deny-all
Preparation:
> clear > add ietf-netconf-acm.yang
Print all user-name elements that occure in data
Command and its output:
> xpath -e //ietf-netconf-acm:user-name data-acm.xml
Result:
Leaflist "user-name" (val: smith)
Leaflist "user-name" (val: smith)
Leaflist "user-name" (val: doe)
Print all data that satisfies condition
Command and its output:
> xpath -e //ietf-netconf-acm:user-name[text()="smith"] data-acm.xml
Result:
Leaflist "user-name" (val: smith)
Leaflist "user-name" (val: smith)
feature in YangPreparation:
> clear > add ietf-interfaces.yang > add ietf-ip.yang > add iana-if-type.yang
Note: This example also shows JSON output of the command.
Command and its output:
> feature -e * ietf-ip
> data -f json -t config data-ip.xml
{
"ietf-interfaces:interfaces": {
"interface": [
{
"name": "eth0",
"description": "Wire Connection",
"type": "iana-if-type:ethernetCsmacd",
"enabled": true,
"ietf-ip:ipv4": {
"address": [
{
"ip": "192.168.1.15",
"netmask": "255.255.255.0"
},
{
"ip": "192.168.1.10",
"netmask": "255.255.255.0"
}
]
}
}
]
}
}