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RFC7895 yang module library implementation (sonic-net#15)
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Added new yang ietf-yang-library.yang, which defines data models for
RFC7895 yang library discovery feature.

New app module yanglib_app.go to handle ietf-yang-library.yang APIs.
REST and gNMI requests for '/ietf-yang-library:modules-state' and its
child paths will be serviced by this app module.

Parses all NB yangs using goyang parser and builds the module info data
tree as per ietf-yang-library.yang. Yangs are parsed upon first request
and cached thereafter.

Uses translib.GetModel() API to identify the yang modules that are
implemented by apps. Other modules are marked as 'import' in yang
library response data. Transformer annotation files (*_annot.yang) are
ignored -- they do not define any data model.

Uses hardcoded module-set-id value for now. Should be changed to use
"yang bundle version" number when yang versioning feature is in.

Yang schema URL is included in the response only if main program set the
root URL through translib.SetSchemaRootURL() API. Schema URL is prepared
by appending the yang file name to the root URL.
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sachinholla committed Jul 30, 2020
1 parent cc01ce4 commit 1d730df
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Showing 7 changed files with 1,000 additions and 5 deletions.
4 changes: 2 additions & 2 deletions Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -81,9 +81,9 @@ $(GOYANG_BIN): $(GO_DEPS)
cd vendor/github.com/openconfig/goyang && \
$(GO) build -o $@ *.go

clean: models-clean translib-clean cvl-clean
clean: models-clean translib-clean cvl-clean go-deps-clean
git check-ignore debian/* | xargs -r $(RM) -r
$(RM) -r $(BUILD_DIR)

cleanall: clean go-deps-clean
cleanall: clean
git clean -fdX tools
2 changes: 2 additions & 0 deletions go.sum
Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,7 @@ github.com/golang/protobuf v1.4.0-rc.1.0.20200221234624-67d41d38c208/go.mod h1:x
github.com/golang/protobuf v1.4.0-rc.2/go.mod h1:LlEzMj4AhA7rCAGe4KMBDvJI+AwstrUpVNzEA03Pprs=
github.com/golang/protobuf v1.4.0-rc.4 h1:+EOh4OY6tjM6ZueeUKinl1f0U2820HzQOuf1iqMnsks=
github.com/golang/protobuf v1.4.0-rc.4/go.mod h1:WU3c8KckQ9AFe+yFwt9sWVRKCVIyN9cPHBJSNnbL67w=
github.com/golang/protobuf v1.4.0-rc.4.0.20200313231945-b860323f09d0 h1:aRz0NBceriICVtjhCgKkDvl+RudKu1CT6h0ZvUTrNfE=
github.com/golang/protobuf v1.4.0-rc.4.0.20200313231945-b860323f09d0/go.mod h1:WU3c8KckQ9AFe+yFwt9sWVRKCVIyN9cPHBJSNnbL67w=
github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
github.com/google/go-cmp v0.3.0/go.mod h1:8QqcDgzrUqlUb/G2PQTWiueGozuR1884gddMywk6iLU=
Expand Down Expand Up @@ -121,6 +122,7 @@ google.golang.org/protobuf v0.0.0-20200228230310-ab0ca4ff8a60/go.mod h1:cfTl7dwQ
google.golang.org/protobuf v1.20.1-0.20200309200217-e05f789c0967/go.mod h1:A+miEFZTKqfCUM6K7xSMQL9OKL/b6hQv+e19PK+JZNE=
google.golang.org/protobuf v1.20.1 h1:ESRXHgpUBG5D2I5mmsQIyYxB/tQIZfSZ8wLyFDf/N/U=
google.golang.org/protobuf v1.20.1/go.mod h1:KqelGeouBkcbcuB3HCk4/YH2tmNLk6YSWA5LIWeI/lY=
google.golang.org/protobuf v1.21.0 h1:qdOKuR/EIArgaWNjetjgTzgVTAZ+S/WXVrq9HW9zimw=
google.golang.org/protobuf v1.21.0/go.mod h1:47Nbq4nVaFHyn7ilMalzfO3qCViNmqZ2kzikPIcrTAo=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
Expand Down
245 changes: 245 additions & 0 deletions models/yang/ietf-yang-library.yang
Original file line number Diff line number Diff line change
@@ -0,0 +1,245 @@
module ietf-yang-library {
namespace "urn:ietf:params:xml:ns:yang:ietf-yang-library";
prefix "yanglib";

import ietf-yang-types {
prefix yang;
}
import ietf-inet-types {
prefix inet;
}

organization
"IETF NETCONF (Network Configuration) Working Group";

contact
"WG Web: <https://datatracker.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
WG Chair: Mehmet Ersue
<mailto:mehmet.ersue@nsn.com>
WG Chair: Mahesh Jethanandani
<mailto:mjethanandani@gmail.com>
Editor: Andy Bierman
<mailto:andy@yumaworks.com>
Editor: Martin Bjorklund
<mailto:mbj@tail-f.com>
Editor: Kent Watsen
<mailto:kwatsen@juniper.net>";

description
"This module contains monitoring information about the YANG
modules and submodules that are used within a YANG-based
server.
Copyright (c) 2016 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 7895; see
the RFC itself for full legal notices.";

revision 2016-06-21 {
description
"Initial revision.";
reference
"RFC 7895: YANG Module Library.";
}

/*
* Typedefs
*/

typedef revision-identifier {
type string {
pattern '\d{4}-\d{2}-\d{2}';
}
description
"Represents a specific date in YYYY-MM-DD format.";
}

/*
* Groupings
*/

grouping module-list {
description
"The module data structure is represented as a grouping
so it can be reused in configuration or another monitoring
data structure.";

grouping common-leafs {
description
"Common parameters for YANG modules and submodules.";

leaf name {
type yang:yang-identifier;
description
"The YANG module or submodule name.";
}
leaf revision {
type union {
type revision-identifier;
type string { length 0; }
}
description
"The YANG module or submodule revision date.
A zero-length string is used if no revision statement
is present in the YANG module or submodule.";
}
}

grouping schema-leaf {
description
"Common schema leaf parameter for modules and submodules.";

leaf schema {
type inet:uri;
description
"Contains a URL that represents the YANG schema
resource for this module or submodule.
This leaf will only be present if there is a URL
available for retrieval of the schema for this entry.";
}
}

list module {
key "name revision";
description
"Each entry represents one revision of one module
currently supported by the server.";

uses common-leafs;
uses schema-leaf;

leaf namespace {
type inet:uri;
mandatory true;
description
"The XML namespace identifier for this module.";
}
leaf-list feature {
type yang:yang-identifier;
description
"List of YANG feature names from this module that are
supported by the server, regardless of whether they are
defined in the module or any included submodule.";
}
list deviation {
key "name revision";
description
"List of YANG deviation module names and revisions
used by this server to modify the conformance of
the module associated with this entry. Note that
the same module can be used for deviations for
multiple modules, so the same entry MAY appear
within multiple 'module' entries.
The deviation module MUST be present in the 'module'
list, with the same name and revision values.
The 'conformance-type' value will be 'implement' for
the deviation module.";
uses common-leafs;
}
leaf conformance-type {
type enumeration {
enum implement {
description
"Indicates that the server implements one or more
protocol-accessible objects defined in the YANG module
identified in this entry. This includes deviation
statements defined in the module.
For YANG version 1.1 modules, there is at most one
module entry with conformance type 'implement' for a
particular module name, since YANG 1.1 requires that,
at most, one revision of a module is implemented.
For YANG version 1 modules, there SHOULD NOT be more
than one module entry for a particular module name.";
}
enum import {
description
"Indicates that the server imports reusable definitions
from the specified revision of the module but does
not implement any protocol-accessible objects from
this revision.
Multiple module entries for the same module name MAY
exist. This can occur if multiple modules import the
same module but specify different revision dates in
the import statements.";
}
}
mandatory true;
description
"Indicates the type of conformance the server is claiming
for the YANG module identified by this entry.";
}
list submodule {
key "name revision";
description
"Each entry represents one submodule within the
parent module.";
uses common-leafs;
uses schema-leaf;
}
}
}

/*
* Operational state data nodes
*/

container modules-state {
config false;
description
"Contains YANG module monitoring information.";

leaf module-set-id {
type string;
mandatory true;
description
"Contains a server-specific identifier representing
the current set of modules and submodules. The
server MUST change the value of this leaf if the
information represented by the 'module' list instances
has changed.";
}

uses module-list;
}

/*
* Notifications
*/

notification yang-library-change {
description
"Generated when the set of modules and submodules supported
by the server has changed.";
leaf module-set-id {
type leafref {
path "/yanglib:modules-state/yanglib:module-set-id";
}
mandatory true;
description
"Contains the module-set-id value representing the
set of modules and submodules supported at the server at
the time the notification is generated.";
}
}

}

25 changes: 22 additions & 3 deletions translib/path_utils.go
Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,12 @@ type PathInfo struct {
Vars map[string]string
}

// HasVar checks if the PathInfo contains given variable.
func (p *PathInfo) HasVar(name string) bool {
_, exists := p.Vars[name]
return exists
}

// Var returns the string value for a path variable. Returns
// empty string if no such variable exists.
func (p *PathInfo) Var(name string) string {
Expand Down Expand Up @@ -91,6 +97,14 @@ func NewPathInfo(path string) *PathInfo {

name := readUntil(r, '=')
value := readUntil(r, ']')

// Handle duplicate parameter names by suffixing "#N" to it.
// N is the number of occurance of that parameter name from left.
namePrefix := name
for k := 2; info.HasVar(name); k++ {
name = fmt.Sprintf("%s#%d", namePrefix, k)
}

if len(name) != 0 {
fmt.Fprintf(&template, "{}")
info.Vars[name] = value
Expand All @@ -104,12 +118,17 @@ func NewPathInfo(path string) *PathInfo {

func readUntil(r *strings.Reader, delim byte) string {
var buff strings.Builder
var escaped bool

for {
c, err := r.ReadByte()
if err == nil && c != delim {
buff.WriteByte(c)
} else {
if err != nil || (c == delim && !escaped) {
break
} else if c == '\\' && !escaped {
escaped = true
} else {
escaped = false
buff.WriteByte(c)
}
}

Expand Down
65 changes: 65 additions & 0 deletions translib/path_utils_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -162,3 +162,68 @@ func TestGetObjectFieldName(t *testing.T) {
}
}
}

func TestNewPathInfo_empty(t *testing.T) {
testPathInfo(t, "", "", mkmap())
}

func TestNewPathInfo_novar(t *testing.T) {
testPathInfo(t, "/test/simple", "/test/simple", mkmap())
}

func TestNewPathInfo_var1(t *testing.T) {
testPathInfo(t, "/test/xx[one=1]", "/test/xx{}", mkmap("one", "1"))
}

func TestNewPathInfo_vars(t *testing.T) {
testPathInfo(t, "/test/xx[one=1][two=2]/new[three=3]", "/test/xx{}{}/new{}",
mkmap("one", "1", "two", "2", "three", "3"))
}

func TestNewPathInfo_dup1(t *testing.T) {
testPathInfo(t, "/test/xx[one=1][two=2]/new[one=0001]", "/test/xx{}{}/new{}",
mkmap("one", "1", "two", "2", "one#2", "0001"))
}

func TestNewPathInfo_dups(t *testing.T) {
testPathInfo(t, "/test/one[xx=1]/two[yy=2]/three[xx=3]/four[zz=4]/five[yy=5]/six[xx=6]",
"/test/one{}/two{}/three{}/four{}/five{}/six{}",
mkmap("xx", "1", "yy", "2", "xx#2", "3", "zz", "4", "yy#2", "5", "xx#3", "6"))
}

func TestNewPathInfo_escaped_name(t *testing.T) {
testPathInfo(t, "/test/xx[one\\==1][two[\\]=2]", "/test/xx{}{}",
mkmap("one=", "1", "two[]", "2"))
}

func TestNewPathInfo_escaped_valu(t *testing.T) {
testPathInfo(t, "/test/xx[one=[1\\]][two=\\0\\02 [\\.\\D]", "/test/xx{}{}",
mkmap("one", "[1]", "two", "002 [.D"))
}

func testPathInfo(t *testing.T, path, expTemplate string, expVars map[string]string) {
info := NewPathInfo(path)
if info == nil {
t.Errorf("NewPathInfo() returned null!")
} else if info.Path != path {
t.Errorf("Expected info.Path = %s", path)
t.Errorf("Actual info.Path = %s", info.Path)
} else if info.Template != expTemplate {
t.Errorf("Expected info.Template = %s", expTemplate)
t.Errorf("Actual info.Template = %s", info.Template)
} else if reflect.DeepEqual(info.Vars, expVars) == false {
t.Errorf("Expected info.Vars = %v", expVars)
t.Errorf("Actual info.Vars = %v", info.Vars)
}
if t.Failed() {
t.Fatalf("NewPathInfo() failed to parse \"%s\"", path)
}
}

func mkmap(args ...string) map[string]string {
m := make(map[string]string)
for i := 0; (i + 1) < len(args); i += 2 {
m[args[i]] = args[i+1]
}
return m
}
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