[8.x] fix(slo): Slices without any data event are considered good (#1…

…96942) (#197434)

# Backport

This will backport the following commits from `main` to `8.x`:
- [fix(slo): Slices without any data event are considered good
(#196942)](#196942)

<!--- Backport version: 9.4.3 -->

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

<!--BACKPORT [{"author":{"name":"Kevin
Delemme","email":"[email protected]"},"sourceCommit":{"committedDate":"2024-10-23T13:03:42Z","message":"fix(slo):
Slices without any data event are considered good
(#196942)","sha":"75f6db10bd1afeeab00bc9265ae7090a197f9e8f","branchLabelMapping":{"^v9.0.0$":"main","^v8.17.0$":"8.x","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["release_note:fix","v9.0.0","backport:prev-major","ci:project-deploy-observability","Team:obs-ux-management","v8.16.0"],"title":"fix(slo):
Slices without any data event are considered
good","number":196942,"url":"https://github.com/elastic/kibana/pull/196942","mergeCommit":{"message":"fix(slo):
Slices without any data event are considered good
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Slices without any data event are considered good
(#196942)","sha":"75f6db10bd1afeeab00bc9265ae7090a197f9e8f"}},{"branch":"8.16","label":"v8.16.0","branchLabelMappingKey":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"state":"NOT_CREATED"}]}]
BACKPORT-->

Co-authored-by: Kevin Delemme <[email protected]>

x-pack/plugins/observability_solution/slo/server/services/transform_generators/apm_transaction_duration.ts

@@ -185,9 +185,9 @@ export class ApmTransactionDurationTransformGenerator extends TransformGenerator
               goodEvents: 'slo.numerator.value',
               totalEvents: 'slo.denominator.value',
             },
-            script: `params.goodEvents / params.totalEvents ${getTimesliceTargetComparator(
+            script: `if (params.totalEvents == 0) { return 1 } else { return params.goodEvents / params.totalEvents ${getTimesliceTargetComparator(
               slo.objective.timesliceTarget!
-            )} ${slo.objective.timesliceTarget} ? 1 : 0`,
+            )} ${slo.objective.timesliceTarget} ? 1 : 0 }`,
           },
         },
       }),

x-pack/plugins/observability_solution/slo/server/services/transform_generators/apm_transaction_error_rate.ts

@@ -168,9 +168,9 @@ export class ApmTransactionErrorRateTransformGenerator extends TransformGenerato
               goodEvents: 'slo.numerator>_count',
               totalEvents: 'slo.denominator>_count',
             },
-            script: `params.goodEvents / params.totalEvents ${getTimesliceTargetComparator(
+            script: `if (params.totalEvents == 0) { return 1 } else { return params.goodEvents / params.totalEvents ${getTimesliceTargetComparator(
               slo.objective.timesliceTarget!
-            )} ${slo.objective.timesliceTarget} ? 1 : 0`,
+            )} ${slo.objective.timesliceTarget} ? 1 : 0 }`,
           },
         },
       }),

x-pack/plugins/observability_solution/slo/server/services/transform_generators/histogram.ts

@@ -101,9 +101,9 @@ export class HistogramTransformGenerator extends TransformGenerator {
               goodEvents: 'slo.numerator>value',
               totalEvents: 'slo.denominator>value',
             },
-            script: `params.goodEvents / params.totalEvents ${getTimesliceTargetComparator(
+            script: `if (params.totalEvents == 0) { return 1 } else { return params.goodEvents / params.totalEvents ${getTimesliceTargetComparator(
               slo.objective.timesliceTarget!
-            )} ${slo.objective.timesliceTarget} ? 1 : 0`,
+            )} ${slo.objective.timesliceTarget} ? 1 : 0 }`,
           },
         },
       }),

x-pack/plugins/observability_solution/slo/server/services/transform_generators/kql_custom.ts

@@ -94,9 +94,9 @@ export class KQLCustomTransformGenerator extends TransformGenerator {
               goodEvents: 'slo.numerator>_count',
               totalEvents: 'slo.denominator>_count',
             },
-            script: `params.goodEvents / params.totalEvents ${getTimesliceTargetComparator(
+            script: `if (params.totalEvents == 0) { return 1 } else { return params.goodEvents / params.totalEvents ${getTimesliceTargetComparator(
               slo.objective.timesliceTarget!
-            )} ${slo.objective.timesliceTarget} ? 1 : 0`,
+            )} ${slo.objective.timesliceTarget} ? 1 : 0 }`,
           },
         },
       }),

x-pack/plugins/observability_solution/slo/server/services/transform_generators/metric_custom.ts

@@ -105,9 +105,9 @@ export class MetricCustomTransformGenerator extends TransformGenerator {
               goodEvents: 'slo.numerator>value',
               totalEvents: 'slo.denominator>value',
             },
-            script: `params.goodEvents / params.totalEvents ${getTimesliceTargetComparator(
+            script: `if (params.totalEvents == 0) { return 1 } else { return params.goodEvents / params.totalEvents ${getTimesliceTargetComparator(
               slo.objective.timesliceTarget!
-            )} ${slo.objective.timesliceTarget} ? 1 : 0`,
+            )} ${slo.objective.timesliceTarget} ? 1 : 0 }`,
           },
         },
       }),