Value mappings: add regex value mapping. (#38931)

packages/grafana-data/src/field/displayProcessor.test.ts

@@ -157,6 +157,50 @@ describe('Format value', () => {
     expect(result.text).toEqual('elva');
   });
 
+  it('should replace a matching regex', () => {
+    const valueMappings: ValueMapping[] = [
+      { type: MappingType.RegexToText, options: { pattern: '([^.]*).example.com', result: { text: '$1' } } },
+    ];
+
+    const instance = getDisplayProcessorFromConfig({ decimals: 1, mappings: valueMappings });
+    const result = instance('hostname.example.com');
+
+    expect(result.text).toEqual('hostname');
+  });
+
+  it('should not replace a non-matching regex', () => {
+    const valueMappings: ValueMapping[] = [
+      { type: MappingType.RegexToText, options: { pattern: '([^.]*).example.com', result: { text: '$1' } } },
+    ];
+
+    const instance = getDisplayProcessorFromConfig({ decimals: 1, mappings: valueMappings });
+    const result = instance('hostname.acme.com');
+
+    expect(result.text).toEqual('hostname.acme.com');
+  });
+
+  it('should empty a matching regex without replacement', () => {
+    const valueMappings: ValueMapping[] = [
+      { type: MappingType.RegexToText, options: { pattern: '([^.]*).example.com', result: { text: '' } } },
+    ];
+
+    const instance = getDisplayProcessorFromConfig({ decimals: 1, mappings: valueMappings });
+    const result = instance('hostname.example.com');
+
+    expect(result.text).toEqual('');
+  });
+
+  it('should not empty a non-matching regex', () => {
+    const valueMappings: ValueMapping[] = [
+      { type: MappingType.RegexToText, options: { pattern: '([^.]*).example.com', result: { text: '' } } },
+    ];
+
+    const instance = getDisplayProcessorFromConfig({ decimals: 1, mappings: valueMappings });
+    const result = instance('hostname.acme.com');
+
+    expect(result.text).toEqual('hostname.acme.com');
+  });
+
   it('should return value with color if mapping has color', () => {
     const valueMappings: ValueMapping[] = [{ type: MappingType.ValueToText, options: { Low: { color: 'red' } } }];
 

packages/grafana-data/src/types/valueMapping.ts

@@ -4,6 +4,7 @@
 export enum MappingType {
   ValueToText = 'value', // was 1
   RangeToText = 'range', // was 2
+  RegexToText = 'regex',
   SpecialValue = 'special',
 }
 
@@ -47,6 +48,21 @@ export interface RangeMap extends BaseValueMap<RangeMapOptions> {
   type: MappingType.RangeToText;
 }
 
+/**
+ * @alpha
+ */
+export interface RegexMapOptions {
+  pattern: string;
+  result: ValueMappingResult;
+}
+
+/**
+ * @alpha
+ */
+export interface RegexMap extends BaseValueMap<RegexMapOptions> {
+  type: MappingType.RegexToText;
+}
+
 /**
  * @alpha
  */
@@ -77,4 +93,4 @@ export interface SpecialValueMap extends BaseValueMap<SpecialValueOptions> {
 /**
  * @alpha
  */
-export type ValueMapping = ValueMap | RangeMap | SpecialValueMap;
+export type ValueMapping = ValueMap | RangeMap | RegexMap | SpecialValueMap;

packages/grafana-data/src/utils/valueMappings.ts

@@ -1,5 +1,6 @@
 import { MappingType, SpecialValueMatch, ThresholdsConfig, ValueMap, ValueMapping, ValueMappingResult } from '../types';
 import { getActiveThreshold } from '../field';
+import { stringToJsRegex } from '../text/string';
 
 export function getValueMappingResult(valueMappings: ValueMapping[], value: any): ValueMappingResult | null {
   for (const vm of valueMappings) {
@@ -38,6 +39,22 @@ export function getValueMappingResult(valueMappings: ValueMapping[], value: any)
 
         return vm.options.result;
 
+      case MappingType.RegexToText:
+        if (value == null) {
+          console.log('null value');
+          continue;
+        }
+
+        if (typeof value !== 'string') {
+          console.log('non-string value', typeof value);
+          continue;
+        }
+
+        const regex = stringToJsRegex(vm.options.pattern);
+        const thisResult = Object.create(vm.options.result);
+        thisResult.text = value.replace(regex, vm.options.result.text || '');
+        return thisResult;
+
       case MappingType.SpecialValue:
         switch (vm.options.match) {
           case SpecialValueMatch.Null: {