promql: use natural sort in sort_by_label and sort_by_label_desc (#13411)

These functions are intended for humans, as robots can already sort the results
however they please. Humans like things sorted "naturally":

* https://blog.codinghorror.com/sorting-for-humans-natural-sort-order/

A similar thing has been done to Grafana, which is also used by humans:

* https://github.com/grafana/grafana/pull/78024
* https://github.com/grafana/grafana/pull/78494

Signed-off-by: Ivan Babrou <github@ivan.computer>

docs/querying/functions.md

@@ -594,6 +594,8 @@ Same as `sort`, but sorts in descending order.
 
 Please note that the sort by label functions only affect the results of instant queries, as range query results always have a fixed output ordering.
 
+This function uses [natural sort order](https://en.wikipedia.org/wiki/Natural_sort_order).
+
 ## `sort_by_label_desc()`
 
 **This function has to be enabled via the [feature flag](../feature_flags/) `--enable-feature=promql-experimental-functions`.**
@@ -602,6 +604,8 @@ Same as `sort_by_label`, but sorts in descending order.
 
 Please note that the sort by label functions only affect the results of instant queries, as range query results always have a fixed output ordering.
 
+This function uses [natural sort order](https://en.wikipedia.org/wiki/Natural_sort_order).
+
 ## `sqrt()`
 
 `sqrt(v instant-vector)` calculates the square root of all elements in `v`.

go.mod

@@ -19,6 +19,7 @@ require (
 	github.com/edsrzf/mmap-go v1.1.0
 	github.com/envoyproxy/go-control-plane v0.11.1
 	github.com/envoyproxy/protoc-gen-validate v1.0.2
+	github.com/facette/natsort v0.0.0-20181210072756-2cd4dd1e2dcb
 	github.com/fsnotify/fsnotify v1.7.0
 	github.com/go-kit/log v0.2.1
 	github.com/go-logfmt/logfmt v0.6.0

go.sum

@@ -166,6 +166,8 @@ github.com/envoyproxy/protoc-gen-validate v1.0.2 h1:QkIBuU5k+x7/QXPvPPnWXWlCdaBF
 github.com/envoyproxy/protoc-gen-validate v1.0.2/go.mod h1:GpiZQP3dDbg4JouG/NNS7QWXpgx6x8QiMKdmN72jogE=
 github.com/evanphx/json-patch v5.6.0+incompatible h1:jBYDEEiFBPxA0v50tFdvOzQQTCvpL6mnFh5mB2/l16U=
 github.com/evanphx/json-patch v5.6.0+incompatible/go.mod h1:50XU6AFN0ol/bzJsmQLiYLvXMP4fmwYFNcr97nuDLSk=
+github.com/facette/natsort v0.0.0-20181210072756-2cd4dd1e2dcb h1:IT4JYU7k4ikYg1SCxNI1/Tieq/NFvh6dzLdgi7eu0tM=
+github.com/facette/natsort v0.0.0-20181210072756-2cd4dd1e2dcb/go.mod h1:bH6Xx7IW64qjjJq8M2u4dxNaBiDfKK+z/3eGDpXEQhc=
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
 github.com/fatih/color v1.9.0/go.mod h1:eQcE1qtQxscV5RaZvpXrrb8Drkc3/DdQ+uUYCNjL+zU=
 github.com/fatih/color v1.13.0/go.mod h1:kLAiJbzzSOZDVNGyDpeOxJ47H46qBXwg5ILebYFFOfk=

promql/functions.go

@@ -21,6 +21,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/facette/natsort"
 	"github.com/grafana/regexp"
 	"github.com/prometheus/common/model"
 	"golang.org/x/exp/slices"
@@ -380,15 +381,16 @@ func funcSortByLabel(vals []parser.Value, args parser.Expressions, enh *EvalNode
 		for _, label := range labels {
 			lv1 := a.Metric.Get(label)
 			lv2 := b.Metric.Get(label)
-			// 0 if a == b, -1 if a < b, and +1 if a > b.
+
-			switch strings.Compare(lv1, lv2) {
+			if lv1 == lv2 {
-			case -1:
-				return -1
-			case +1:
-				return +1
-			default:
 				continue
 			}
+
+			if natsort.Compare(lv1, lv2) {
+				return -1
+			}
+
+			return +1
 		}
 
 		return 0
@@ -409,19 +411,16 @@ func funcSortByLabelDesc(vals []parser.Value, args parser.Expressions, enh *Eval
 		for _, label := range labels {
 			lv1 := a.Metric.Get(label)
 			lv2 := b.Metric.Get(label)
-			// If label values are the same, continue to the next label
+
 			if lv1 == lv2 {
 				continue
 			}
-			// 0 if a == b, -1 if a < b, and +1 if a > b.
+
-			switch strings.Compare(lv1, lv2) {
+			if natsort.Compare(lv1, lv2) {
-			case -1:
 				return +1
-			case +1:
-				return -1
-			default:
-				continue
 			}
+
+			return -1
 		}
 
 		return 0

promql/testdata/functions.test

@@ -482,6 +482,19 @@ load 5m
 	http_requests{job="app-server", instance="0", group="canary"}		0+70x10
 	http_requests{job="app-server", instance="1", group="canary"}		0+80x10
 	http_requests{job="api-server", instance="2", group="production"}	0+10x10
+	cpu_time_total{job="cpu", cpu="0"} 0+10x10
+	cpu_time_total{job="cpu", cpu="1"} 0+10x10
+	cpu_time_total{job="cpu", cpu="2"} 0+10x10
+	cpu_time_total{job="cpu", cpu="3"} 0+10x10
+	cpu_time_total{job="cpu", cpu="10"} 0+10x10
+	cpu_time_total{job="cpu", cpu="11"} 0+10x10
+	cpu_time_total{job="cpu", cpu="12"} 0+10x10
+	cpu_time_total{job="cpu", cpu="20"} 0+10x10
+	cpu_time_total{job="cpu", cpu="21"} 0+10x10
+	cpu_time_total{job="cpu", cpu="100"} 0+10x10
+	node_uname_info{job="node_exporter", instance="4m600", release="1.2.3"} 0+10x10
+	node_uname_info{job="node_exporter", instance="4m5", release="1.11.3"} 0+10x10
+	node_uname_info{job="node_exporter", instance="4m1000", release="1.111.3"} 0+10x10
 
 eval_ordered instant at 50m sort_by_label(http_requests, "instance")
 	http_requests{group="production", instance="0", job="api-server"} 100
@@ -579,6 +592,28 @@ eval_ordered instant at 50m sort_by_label_desc(http_requests, "instance", "group
 	http_requests{group="canary", instance="0", job="app-server"} 700
 	http_requests{group="canary", instance="0", job="api-server"} 300
 
+eval_ordered instant at 50m sort_by_label(cpu_time_total, "cpu")
+	cpu_time_total{job="cpu", cpu="0"} 100
+	cpu_time_total{job="cpu", cpu="1"} 100
+	cpu_time_total{job="cpu", cpu="2"} 100
+	cpu_time_total{job="cpu", cpu="3"} 100
+	cpu_time_total{job="cpu", cpu="10"} 100
+	cpu_time_total{job="cpu", cpu="11"} 100
+	cpu_time_total{job="cpu", cpu="12"} 100
+	cpu_time_total{job="cpu", cpu="20"} 100
+	cpu_time_total{job="cpu", cpu="21"} 100
+	cpu_time_total{job="cpu", cpu="100"} 100
+
+eval_ordered instant at 50m sort_by_label(node_uname_info, "instance")
+	node_uname_info{job="node_exporter", instance="4m5", release="1.11.3"} 100
+	node_uname_info{job="node_exporter", instance="4m600", release="1.2.3"} 100
+	node_uname_info{job="node_exporter", instance="4m1000", release="1.111.3"} 100
+
+eval_ordered instant at 50m sort_by_label(node_uname_info, "release")
+	node_uname_info{job="node_exporter", instance="4m600", release="1.2.3"} 100
+	node_uname_info{job="node_exporter", instance="4m5", release="1.11.3"} 100
+	node_uname_info{job="node_exporter", instance="4m1000", release="1.111.3"} 100
+
 # Tests for holt_winters
 clear