[release-11.5.3] InfluxDB: Improve handling of template variables contained in regular expressions (InfluxQL) (#100977)

InfluxDB: Improve handling of template variables contained in regular expressions (InfluxQL) (#100762)

* Improve handling of template vars in regex

* Review

* Minor update

(cherry picked from commit 8b3047ba1e)

Co-authored-by: Andreas Christou <andreas.christou@grafana.com>

public/app/plugins/datasource/influxdb/datasource.test.ts

@@ -363,6 +363,18 @@ describe('interpolateQueryExpr', () => {
     expect(result).toBe(expectation);
   });
 
+  it('should **not** return the escaped value if the value **is not** wrapped in regex and the query is more complex (e.g. text is contained between two / but not a regex', () => {
+    const value = 'testmatch';
+    const variableMock = queryBuilder().withId('tempVar').withName('tempVar').withMulti(false).build();
+    const result = ds.interpolateQueryExpr(
+      value,
+      variableMock,
+      `select value where ("tag"::tag =~ /value/) AND where other = $tempVar $timeFilter GROUP BY time($__interval) tz('Europe/London')`
+    );
+    const expectation = `testmatch`;
+    expect(result).toBe(expectation);
+  });
+
   it('should return floating point number as it is', () => {
     const variableMock = queryBuilder()
       .withId('tempVar')

public/app/plugins/datasource/influxdb/datasource.ts

@@ -351,17 +351,30 @@ export default class InfluxDatasource extends DataSourceWithBackend<InfluxQuery,
     // If the variable is not a multi-value variable
     // we want to see how it's been used. If it is used in a regex expression
     // we escape it. Otherwise, we return it directly.
-    // regex below checks if the variable inside /^...$/ (^ and $ is optional)
+    // The regex below searches for regexes within the query string
+    const regexMatcher = new RegExp(
+      /\/((?![*+?])(?:[^\r\n\[/\\]|\\.|\[(?:[^\r\n\]\\]|\\.)*\])+)\/((?:g(?:im?|mi?)?|i(?:gm?|mg?)?|m(?:gi?|ig?)?)?)/,
+      'gm'
+    );
+    // If matches are found this regex is evaluated to check if the variable is contained in the regex /^...$/ (^ and $ is optional)
     // i.e. /^$myVar$/ or /$myVar/ or /^($myVar)$/
     const regex = new RegExp(`\\/(?:\\^)?(.*)(\\$${variable.name})(.*)(?:\\$)?\\/`, 'gm');
-    if (query && regex.test(query)) {
-      if (typeof value === 'string') {
-        return escapeRegex(value);
+    if (!query) {
+      return value;
+    }
+
+    const queryMatches = query.match(regexMatcher);
+    if (!queryMatches) {
+      return value;
+    }
+    for (const match of queryMatches) {
+      if (!match.match(regex)) {
+        continue;
       }
 
       // If the value is a string array first escape them then join them with pipe
       // then put inside parenthesis.
-      return `(${value.map((v) => escapeRegex(v)).join('|')})`;
+      return typeof value === 'string' ? escapeRegex(value) : `(${value.map((v) => escapeRegex(v)).join('|')})`;
     }
 
     return value;