[8.10] chore(slo): optional filter fields (#164630) (#164699)

# Backport

This will backport the following commits from `main` to `8.10`:
- [chore(slo): optional filter fields
(#164630)](https://github.com/elastic/kibana/pull/164630)

<!--- Backport version: 8.9.7 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

<!--BACKPORT [{"author":{"name":"Kevin
Delemme","email":"kevin.delemme@elastic.co"},"sourceCommit":{"committedDate":"2023-08-24T12:09:31Z","message":"chore(slo):
optional filter fields
(#164630)","sha":"65573fc93e95d4f64e323b8c1f7bd0cb417414b6","branchLabelMapping":{"^v8.11.0$":"main","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["backport","release_note:skip","Team:
Actionable
Observability","v8.10.0","v8.11.0"],"number":164630,"url":"https://github.com/elastic/kibana/pull/164630","mergeCommit":{"message":"chore(slo):
optional filter fields
(#164630)","sha":"65573fc93e95d4f64e323b8c1f7bd0cb417414b6"}},"sourceBranch":"main","suggestedTargetBranches":["8.10"],"targetPullRequestStates":[{"branch":"8.10","label":"v8.10.0","labelRegex":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"state":"NOT_CREATED"},{"branch":"main","label":"v8.11.0","labelRegex":"^v8.11.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/164630","number":164630,"mergeCommit":{"message":"chore(slo):
optional filter fields
(#164630)","sha":"65573fc93e95d4f64e323b8c1f7bd0cb417414b6"}}]}]
BACKPORT-->

Co-authored-by: Kevin Delemme <kevin.delemme@elastic.co>

x-pack/packages/kbn-slo-schema/src/schema/indicators.ts

@@ -46,13 +46,17 @@ const apmTransactionErrorRateIndicatorSchema = t.type({
 const kqlCustomIndicatorTypeSchema = t.literal('sli.kql.custom');
 const kqlCustomIndicatorSchema = t.type({
   type: kqlCustomIndicatorTypeSchema,
-  params: t.type({
-    index: t.string,
-    filter: t.string,
-    good: t.string,
-    total: t.string,
-    timestampField: t.string,
-  }),
+  params: t.intersection([
+    t.type({
+      index: t.string,
+      good: t.string,
+      total: t.string,
+      timestampField: t.string,
+    }),
+    t.partial({
+      filter: t.string,
+    }),
+  ]),
 });
 
 const metricCustomValidAggregations = t.keyof({
@@ -76,13 +80,17 @@ const metricCustomMetricDef = t.type({
 const metricCustomIndicatorTypeSchema = t.literal('sli.metric.custom');
 const metricCustomIndicatorSchema = t.type({
   type: metricCustomIndicatorTypeSchema,
-  params: t.type({
-    index: t.string,
-    filter: t.string,
-    good: metricCustomMetricDef,
-    total: metricCustomMetricDef,
-    timestampField: t.string,
-  }),
+  params: t.intersection([
+    t.type({
+      index: t.string,
+      good: metricCustomMetricDef,
+      total: metricCustomMetricDef,
+      timestampField: t.string,
+    }),
+    t.partial({
+      filter: t.string,
+    }),
+  ]),
 });
 
 const rangeHistogramMetricType = t.literal('range');
@@ -117,13 +125,17 @@ const histogramMetricDef = t.union([
 const histogramIndicatorTypeSchema = t.literal('sli.histogram.custom');
 const histogramIndicatorSchema = t.type({
   type: histogramIndicatorTypeSchema,
-  params: t.type({
-    index: t.string,
-    timestampField: t.string,
-    filter: t.string,
-    good: histogramMetricDef,
-    total: histogramMetricDef,
-  }),
+  params: t.intersection([
+    t.type({
+      index: t.string,
+      timestampField: t.string,
+      good: histogramMetricDef,
+      total: histogramMetricDef,
+    }),
+    t.partial({
+      filter: t.string,
+    }),
+  ]),
 });
 
 const indicatorDataSchema = t.type({

x-pack/plugins/observability/docs/openapi/slo/bundled.json

@@ -798,7 +798,9 @@
             "nullable": false,
             "required": [
               "index",
-              "timestampField"
+              "timestampField",
+              "good",
+              "total"
             ],
             "properties": {
               "index": {

x-pack/plugins/observability/docs/openapi/slo/bundled.yaml

@@ -504,6 +504,8 @@ components:
           required:
             - index
             - timestampField
+            - good
+            - total
           properties:
             index:
               description: The index or index pattern to use

x-pack/plugins/observability/docs/openapi/slo/components/schemas/indicator_properties_custom_kql.yaml

@@ -12,6 +12,8 @@ properties:
     required:
       - index
       - timestampField
+      - good
+      - total
     properties:
       index:
         description: The index or index pattern to use

x-pack/plugins/observability/server/services/slo/get_preview_data.ts

@@ -316,7 +316,7 @@ export class GetPreviewData {
   }
 }
 
-function getElastichsearchQueryOrThrow(kuery: string) {
+function getElastichsearchQueryOrThrow(kuery: string | undefined = '') {
   try {
     return toElasticsearchQuery(fromKueryExpression(kuery));
   } catch (err) {

x-pack/plugins/observability/server/services/slo/transform_generators/common.ts

@@ -8,7 +8,7 @@
 import { fromKueryExpression, toElasticsearchQuery } from '@kbn/es-query';
 import { InvalidTransformError } from '../../../errors';
 
-export function getElastichsearchQueryOrThrow(kuery: string) {
+export function getElastichsearchQueryOrThrow(kuery: string | undefined = '') {
   try {
     return toElasticsearchQuery(fromKueryExpression(kuery));
   } catch (err) {