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Add ComparePath func (#787)
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* Add ComparePath func

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@DanG100
DanG100 authored Feb 17, 2023
1 parent 4123dde commit 1f980b3
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Showing 2 changed files with 241 additions and 12 deletions.
98 changes: 98 additions & 0 deletions util/gnmi.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -255,3 +255,101 @@ func JoinPaths(prefix, suffix *gpb.Path) (*gpb.Path, error) {
}
return joined, nil
}

// CompareRelation describes of the relation between to gNMI paths.
type CompareRelation int

const (
// Equal means the paths are the same.
Equal CompareRelation = iota
// Disjoint means the paths do not overlap at all.
Disjoint
// Subset means a path is strictly smaller than the other.
Subset
// Superset means a path is strictly larger than the other.
Superset
// PartialIntersect means a path partial overlaps the other.
PartialIntersect
)

// ComparePaths returns the set relation between two paths.
// It returns an error if the paths are invalid or not one of the relations.
func ComparePaths(a, b *gpb.Path) CompareRelation {
if a.Origin != b.Origin {
return Disjoint
}

shortestLen := len(a.Elem)

// If path a is longer than b, then we start by assuming a subset relationship, and vice versa.
// Otherwise assume paths are equal.
relation := Equal
if len(a.Elem) > len(b.Elem) {
relation = Subset
shortestLen = len(b.Elem)
} else if len(a.Elem) < len(b.Elem) {
relation = Superset
}

for i := 0; i < shortestLen; i++ {
elemRelation := comparePathElem(a.Elem[i], b.Elem[i])
switch elemRelation {
case PartialIntersect, Disjoint:
return elemRelation
case Superset, Subset:
if relation == Equal {
relation = elemRelation
} else if elemRelation != relation {
return PartialIntersect
}
}
}

return relation
}

// comparePathElem compare two path elements a, b and returns:
// subset: if every definite key in a is wildcard in b.
// superset: if every wildcard key in b is non-wildcard in b.
// error: not two keys are both subset and superset.
func comparePathElem(a, b *gpb.PathElem) CompareRelation {
if a.Name != b.Name {
return Disjoint
}

// Start by assuming a perfect match. Then relax this property as we scan through the key values.
setRelation := Equal
for k, aVal := range a.Key {
bVal, ok := b.Key[k]
switch {
case aVal == bVal, aVal == "*" && !ok: // Values are equal (possibly be implicit wildcards).
continue
case aVal == "*": // Values not equal, a value is superset of b value.
if setRelation == Subset {
return PartialIntersect
}
setRelation = Superset
case bVal == "*", !ok: // Values not equal, a value is subset of b value.
if setRelation == Superset {
return PartialIntersect
}
setRelation = Subset
default: // Values not equal, but of the same size.
return Disjoint
}
}
for k, bVal := range b.Key {
_, ok := a.Key[k]
switch {
case ok, bVal == "*": // Key has already been visited, or values are equal.
continue
case bVal != "*": // If a contains an implicit wildcard and b isn't.
if setRelation == Subset {
return PartialIntersect
}
setRelation = Superset
}
}

return setRelation
}
155 changes: 143 additions & 12 deletions util/gnmi_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,7 @@
// See the License for the specific language governing permissions and
// limitations under the License.

package util
package util_test

import (
"strings"
Expand All @@ -21,6 +21,8 @@ import (
"github.com/google/go-cmp/cmp"
"github.com/openconfig/gnmi/errdiff"
"github.com/openconfig/goyang/pkg/yang"
"github.com/openconfig/ygot/util"
"github.com/openconfig/ygot/ygot"
"google.golang.org/protobuf/encoding/prototext"
"google.golang.org/protobuf/proto"
"google.golang.org/protobuf/testing/protocmp"
Expand Down Expand Up @@ -123,7 +125,7 @@ func TestPathMatchesPrefix(t *testing.T) {

for _, tt := range tests {
t.Run(tt.desc, func(t *testing.T) {
if got, want := PathMatchesPrefix(pathNoKeysToGNMIPath(tt.path), strings.Split(tt.prefix, "/")), tt.want; got != want {
if got, want := util.PathMatchesPrefix(pathNoKeysToGNMIPath(tt.path), strings.Split(tt.prefix, "/")), tt.want; got != want {
t.Errorf("%s: got: %v want: %v", tt.desc, got, want)
}
})
Expand Down Expand Up @@ -191,7 +193,7 @@ func TestTrimGNMIPathPrefix(t *testing.T) {
t.Run(tt.desc, func(t *testing.T) {
path := pathNoKeysToGNMIPath(tt.path)
prefix := strings.Split(tt.prefix, "/")
got := gnmiPathNoKeysToPath(TrimGNMIPathPrefix(path, prefix))
got := gnmiPathNoKeysToPath(util.TrimGNMIPathPrefix(path, prefix))
if got != tt.want {
t.Errorf("%s: got: %s want: %s", tt.desc, got, tt.want)
}
Expand Down Expand Up @@ -229,7 +231,7 @@ func TestPopGNMIPath(t *testing.T) {

for _, tt := range tests {
t.Run(tt.desc, func(t *testing.T) {
if got, want := gnmiPathNoKeysToPath(PopGNMIPath(pathNoKeysToGNMIPath(tt.path))), tt.want; got != want {
if got, want := gnmiPathNoKeysToPath(util.PopGNMIPath(pathNoKeysToGNMIPath(tt.path))), tt.want; got != want {
t.Errorf("%s: got: %s want: %s", tt.desc, got, want)
}
})
Expand Down Expand Up @@ -325,7 +327,7 @@ func TestPathElemsEqual(t *testing.T) {

for _, tt := range tests {
t.Run(tt.desc, func(t *testing.T) {
if got := PathElemsEqual(tt.lhs, tt.rhs); got != tt.want {
if got := util.PathElemsEqual(tt.lhs, tt.rhs); got != tt.want {
t.Fatalf("did not get expected result, got: %v, want: %v", got, tt.want)
}
})
Expand Down Expand Up @@ -424,7 +426,7 @@ func TestPathElemSlicesEqual(t *testing.T) {

for _, tt := range tests {
t.Run(tt.desc, func(t *testing.T) {
if got := PathElemSlicesEqual(tt.inElemsA, tt.inElemsB); got != tt.want {
if got := util.PathElemSlicesEqual(tt.inElemsA, tt.inElemsB); got != tt.want {
t.Fatalf("did not get expected result, got: %v, want: %v", got, tt.want)
}
})
Expand Down Expand Up @@ -519,7 +521,7 @@ func TestPathMatchesPathElemPrefix(t *testing.T) {

for _, tt := range tests {
t.Run(tt.desc, func(t *testing.T) {
if got := PathMatchesPathElemPrefix(tt.inPath, tt.inPrefix); got != tt.want {
if got := util.PathMatchesPathElemPrefix(tt.inPath, tt.inPrefix); got != tt.want {
t.Fatalf("did not get expected result, got: %v, want: %v", got, tt.want)
}
})
Expand Down Expand Up @@ -746,7 +748,7 @@ func TestPathMatchesQuery(t *testing.T) {
}}
for _, tt := range tests {
t.Run(tt.desc, func(t *testing.T) {
if got := PathMatchesQuery(tt.inPath, tt.inQuery); got != tt.want {
if got := util.PathMatchesQuery(tt.inPath, tt.inQuery); got != tt.want {
t.Fatalf("did not get expected result, got: %v, want: %v", got, tt.want)
}
})
Expand Down Expand Up @@ -836,7 +838,7 @@ func TestTrimGNMIPathElemPrefix(t *testing.T) {

for _, tt := range tests {
t.Run(tt.desc, func(t *testing.T) {
if got := TrimGNMIPathElemPrefix(tt.inPath, tt.inPrefix); !proto.Equal(got, tt.want) {
if got := util.TrimGNMIPathElemPrefix(tt.inPath, tt.inPrefix); !proto.Equal(got, tt.want) {
t.Fatalf("did not get expected path, got: %s, want: %s", prototext.Format(got), prototext.Format(tt.want))
}
})
Expand Down Expand Up @@ -872,7 +874,7 @@ func TestFindPathElemPrefix(t *testing.T) {
}}

for _, tt := range tests {
if got := FindPathElemPrefix(tt.inPaths); !proto.Equal(got, tt.want) {
if got := util.FindPathElemPrefix(tt.inPaths); !proto.Equal(got, tt.want) {
t.Errorf("%s: FindPathElemPrefix(%v): did not get expected prefix, got: %s, want: %s", tt.name, tt.inPaths, prototext.Format(got), prototext.Format(tt.want))
}
}
Expand Down Expand Up @@ -979,7 +981,7 @@ func TestFindModelData(t *testing.T) {
}}

for _, tt := range tests {
got, err := FindModelData(tt.in)
got, err := util.FindModelData(tt.in)

if diff := errdiff.Substring(err, tt.wantErrSubstring); diff != "" {
t.Errorf("%s: FindModelData(%v): did not get expected error, %s", tt.name, tt.in, diff)
Expand Down Expand Up @@ -1039,7 +1041,7 @@ func TestJoinPaths(t *testing.T) {

for _, tt := range tests {
t.Run(tt.desc, func(t *testing.T) {
got, err := JoinPaths(tt.prefix, tt.suffix)
got, err := util.JoinPaths(tt.prefix, tt.suffix)
if diff := errdiff.Substring(err, tt.wantErrSubstring); diff != "" {
t.Errorf("JoinPaths(%v, %v) got unexpected error diff: %s", tt.prefix, tt.suffix, diff)
}
Expand All @@ -1052,3 +1054,132 @@ func TestJoinPaths(t *testing.T) {
})
}
}

func mustStringToPath(t testing.TB, path string) *gpb.Path {
p, err := ygot.StringToStructuredPath(path)
if err != nil {
t.Fatal(err)
}
return p
}

func TestComparePaths(t *testing.T) {
tests := []struct {
desc string
a, b *gpb.Path
want util.CompareRelation
}{{
desc: "different origins",
a: &gpb.Path{Origin: "foo"},
b: &gpb.Path{Origin: "bar"},
want: util.Disjoint,
}, {
desc: "disjoint paths",
a: mustStringToPath(t, "/foo"),
b: mustStringToPath(t, "/bar"),
want: util.Disjoint,
}, {
desc: "disjoint paths by list keys",
a: mustStringToPath(t, "/foo[a=1][b=2]"),
b: mustStringToPath(t, "/foo[a=1][b=3]"),
want: util.Disjoint,
}, {
desc: "equal paths",
a: mustStringToPath(t, "/foo"),
b: mustStringToPath(t, "/foo"),
want: util.Equal,
}, {
desc: "equal paths with list keys",
a: mustStringToPath(t, "/foo[a=1]"),
b: mustStringToPath(t, "/foo[a=1]"),
want: util.Equal,
}, {
desc: "equal paths with implicit wildcards",
a: mustStringToPath(t, "/foo[a=*]"),
b: mustStringToPath(t, "/foo"),
want: util.Equal,
}, {
desc: "equal paths with implicit wildcards",
a: mustStringToPath(t, "/foo"),
b: mustStringToPath(t, "/foo[a=*]"),
want: util.Equal,
}, {
desc: "superset by length",
a: mustStringToPath(t, "/foo"),
b: mustStringToPath(t, "/foo/bar"),
want: util.Superset,
}, {
desc: "superset by length and keys",
a: mustStringToPath(t, "/foo[a=*]"),
b: mustStringToPath(t, "/foo[b=1]/bar"),
want: util.Superset,
}, {
desc: "superset by list keys",
a: mustStringToPath(t, "/foo[a=*]"),
b: mustStringToPath(t, "/foo[a=1]"),
want: util.Superset,
}, {
desc: "superset by list keys implicit wildcard",
a: mustStringToPath(t, "/foo"),
b: mustStringToPath(t, "/foo[a=1]"),
want: util.Superset,
}, {
desc: "subset by length",
a: mustStringToPath(t, "/foo/bar"),
b: mustStringToPath(t, "/foo"),
want: util.Subset,
}, {
desc: "subset by length and keys",
a: mustStringToPath(t, "/foo[a=1]/bar"),
b: mustStringToPath(t, "/foo[b=*]"),
want: util.Subset,
}, {
desc: "subset by list keys",
a: mustStringToPath(t, "/foo[a=1]"),
b: mustStringToPath(t, "/foo[a=*]"),
want: util.Subset,
}, {
desc: "subset by list keys implicit wildcard",
a: mustStringToPath(t, "/foo[a=1]"),
b: mustStringToPath(t, "/foo"),
want: util.Subset,
}, {
desc: "error single elem is both subset and superset",
a: mustStringToPath(t, "/foo[a=1][b=*]"),
b: mustStringToPath(t, "/foo[a=*][b=1]"),
want: util.PartialIntersect,
}, {
desc: "error single elem is both subset and superset implicit wildcards",
a: mustStringToPath(t, "/foo[a=1]"),
b: mustStringToPath(t, "/foo[b=1]"),
want: util.PartialIntersect,
}, {
desc: "error path is both subset and superset",
a: mustStringToPath(t, "/foo[a=*]/bar[b=1]"),
b: mustStringToPath(t, "/foo[b=1]/bar[b=*]"),
want: util.PartialIntersect,
}, {
desc: "error path elem is both subset and superset",
a: mustStringToPath(t, "/foo[a=1]/bar[b=*]"),
b: mustStringToPath(t, "/foo[b=*]/bar[b=1]"),
want: util.PartialIntersect,
}, {
desc: "error shorter path is both subset and superset",
a: mustStringToPath(t, "/foo[a=*]/bar"),
b: mustStringToPath(t, "/foo[b=1]"),
want: util.PartialIntersect,
}, {
desc: "error path elem is both subset and superset",
a: mustStringToPath(t, "/foo[a=1]"),
b: mustStringToPath(t, "/foo[b=*]/bar"),
want: util.PartialIntersect,
}}
for _, tt := range tests {
t.Run(tt.desc, func(t *testing.T) {
got := util.ComparePaths(tt.a, tt.b)
if got != tt.want {
t.Errorf("ComparePaths(%v, %v) got unexpected result: got %v, want %v", tt.a, tt.b, got, tt.want)
}
})
}
}

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