CR changes

Eppo-exp · Aug 2, 2024 · 4026acc · 4026acc
1 parent 89a5e6b
commit 4026acc
Show file tree

Hide file tree

Showing 4 changed files with 139 additions and 126 deletions.
diff --git a/src/client/eppo-client.ts b/src/client/eppo-client.ts
@@ -24,6 +24,7 @@ import {
   FlagEvaluationDetailsBuilder,
   IFlagEvaluationDetails,
 } from '../flag-evaluation-details-builder';
+import { FlagEvaluationError } from '../flag-evaluation-error';
 import FetchHttpClient from '../http-client';
 import {
   BanditParameters,
@@ -693,16 +694,23 @@ export default class EppoClient {
       };
     } catch (error) {
       const eppoValue = this.rethrowIfNotGraceful(error, defaultValue);
-      const flagEvaluationDetails = new FlagEvaluationDetailsBuilder(
-        '',
-        [],
-        '',
-        '',
-      ).buildForNoneResult('ASSIGNMENT_ERROR', `Assignment Error: ${error.message}`);
-      return {
-        eppoValue,
-        flagEvaluationDetails,
-      };
+      if (error instanceof FlagEvaluationError && error.flagEvaluationDetails) {
+        return {
+          eppoValue,
+          flagEvaluationDetails: error.flagEvaluationDetails,
+        };
+      } else {
+        const flagEvaluationDetails = new FlagEvaluationDetailsBuilder(
+          '',
+          [],
+          '',
+          '',
+        ).buildForNoneResult('ASSIGNMENT_ERROR', `Assignment Error: ${error.message}`);
+        return {
+          eppoValue,
+          flagEvaluationDetails,
+        };
+      }
     }
   }
 

diff --git a/src/evaluator.ts b/src/evaluator.ts
@@ -1,11 +1,11 @@
 import { checkValueTypeMatch } from './client/eppo-client';
 import {
-  AllocationEvaluation,
   AllocationEvaluationCode,
   IFlagEvaluationDetails,
   FlagEvaluationDetailsBuilder,
   FlagEvaluationCode,
 } from './flag-evaluation-details-builder';
+import { FlagEvaluationError } from './flag-evaluation-error';
 import {
   Flag,
   Shard,
@@ -52,97 +52,99 @@ export class Evaluator {
       configDetails.configFetchedAt,
       configDetails.configPublishedAt,
     );
+    try {
+      if (!flag.enabled) {
+        return noneResult(
+          flag.key,
+          subjectKey,
+          subjectAttributes,
+          flagEvaluationDetailsBuilder.buildForNoneResult(
+            'FLAG_UNRECOGNIZED_OR_DISABLED',
+            `Unrecognized or disabled flag: ${flag.key}`,
+          ),
+        );
+      }
+
+      const now = new Date();
+      for (let i = 0; i < flag.allocations.length; i++) {
+        const allocation = flag.allocations[i];
+        const addUnmatchedAllocation = (code: AllocationEvaluationCode) => {
+          flagEvaluationDetailsBuilder.addUnmatchedAllocation({
+            key: allocation.key,
+            allocationEvaluationCode: code,
+            orderPosition: i + 1,
+          });
+        };
 
-    if (!flag.enabled) {
+        if (allocation.startAt && now < new Date(allocation.startAt)) {
+          addUnmatchedAllocation(AllocationEvaluationCode.BEFORE_START_TIME);
+          continue;
+        }
+        if (allocation.endAt && now > new Date(allocation.endAt)) {
+          addUnmatchedAllocation(AllocationEvaluationCode.AFTER_END_TIME);
+          continue;
+        }
+        const { matched, matchedRule } = matchesRules(
+          allocation?.rules ?? [],
+          { id: subjectKey, ...subjectAttributes },
+          obfuscated,
+        );
+        if (matched) {
+          for (const split of allocation.splits) {
+            if (
+              split.shards.every((shard) => this.matchesShard(shard, subjectKey, flag.totalShards))
+            ) {
+              const variation = flag.variations[split.variationKey];
+              const { flagEvaluationCode, flagEvaluationDescription } =
+                this.getMatchedEvaluationCodeAndDescription(
+                  variation,
+                  allocation,
+                  split,
+                  subjectKey,
+                  expectedVariationType,
+                );
+              const flagEvaluationDetails = flagEvaluationDetailsBuilder
+                .setMatch(i, variation, allocation, matchedRule, expectedVariationType)
+                .build(flagEvaluationCode, flagEvaluationDescription);
+              return {
+                flagKey: flag.key,
+                subjectKey,
+                subjectAttributes,
+                allocationKey: allocation.key,
+                variation,
+                extraLogging: split.extraLogging ?? {},
+                doLog: allocation.doLog,
+                flagEvaluationDetails,
+              };
+            }
+          }
+          // matched, but does not fall within split range
+          addUnmatchedAllocation(AllocationEvaluationCode.TRAFFIC_EXPOSURE_MISS);
+        } else {
+          addUnmatchedAllocation(AllocationEvaluationCode.FAILING_RULE);
+        }
+      }
       return noneResult(
         flag.key,
         subjectKey,
         subjectAttributes,
         flagEvaluationDetailsBuilder.buildForNoneResult(
-          'FLAG_UNRECOGNIZED_OR_DISABLED',
-          `Unrecognized or disabled flag: ${flag.key}`,
+          'DEFAULT_ALLOCATION_NULL',
+          'No allocations matched. Falling back to "Default Allocation", serving NULL',
         ),
       );
-    }
-
-    const now = new Date();
-    const unmatchedAllocations: Array<AllocationEvaluation> = [];
-    for (let i = 0; i < flag.allocations.length; i++) {
-      const allocation = flag.allocations[i];
-      const addUnmatchedAllocation = (code: AllocationEvaluationCode) => {
-        unmatchedAllocations.push({
-          key: allocation.key,
-          allocationEvaluationCode: code,
-          orderPosition: i + 1,
-        });
-      };
-
-      if (allocation.startAt && now < new Date(allocation.startAt)) {
-        addUnmatchedAllocation(AllocationEvaluationCode.BEFORE_START_TIME);
-        continue;
-      }
-      if (allocation.endAt && now > new Date(allocation.endAt)) {
-        addUnmatchedAllocation(AllocationEvaluationCode.AFTER_END_TIME);
-        continue;
-      }
-      const { matched, matchedRule } = matchesRules(
-        allocation?.rules ?? [],
-        { id: subjectKey, ...subjectAttributes },
-        obfuscated,
+    } catch (err) {
+      const flagEvaluationDetails = flagEvaluationDetailsBuilder.gracefulBuild(
+        'ASSIGNMENT_ERROR',
+        `Assignment Error: ${err.message}`,
       );
-      if (matched) {
-        for (const split of allocation.splits) {
-          if (
-            split.shards.every((shard) => this.matchesShard(shard, subjectKey, flag.totalShards))
-          ) {
-            const variation = flag.variations[split.variationKey];
-            const { flagEvaluationCode, flagEvaluationDescription } =
-              this.getMatchedEvaluationCodeAndDescription(
-                variation,
-                allocation,
-                split,
-                subjectKey,
-                expectedVariationType,
-              );
-            const flagEvaluationDetails = flagEvaluationDetailsBuilder
-              .setMatch(
-                i,
-                variation,
-                allocation,
-                matchedRule,
-                unmatchedAllocations,
-                expectedVariationType,
-              )
-              .build(flagEvaluationCode, flagEvaluationDescription);
-            return {
-              flagKey: flag.key,
-              subjectKey,
-              subjectAttributes,
-              allocationKey: allocation.key,
-              variation,
-              extraLogging: split.extraLogging ?? {},
-              doLog: allocation.doLog,
-              flagEvaluationDetails,
-            };
-          }
-        }
-        // matched, but does not fall within split range
-        addUnmatchedAllocation(AllocationEvaluationCode.TRAFFIC_EXPOSURE_MISS);
-      } else {
-        addUnmatchedAllocation(AllocationEvaluationCode.FAILING_RULE);
+      if (flagEvaluationDetails) {
+        const flagEvaluationError = new FlagEvaluationError(err.message);
+        flagEvaluationError.flagEvaluationDetails = flagEvaluationDetails;
+        throw flagEvaluationError;
       }
+      throw err;
     }
-    return noneResult(
-      flag.key,
-      subjectKey,
-      subjectAttributes,
-      flagEvaluationDetailsBuilder
-        .setNoMatchFound(unmatchedAllocations)
-        .build(
-          'DEFAULT_ALLOCATION_NULL',
-          'No allocations matched. Falling back to "Default Allocation", serving NULL',
-        ),
-    );
   }
 
   matchesShard(shard: Shard, subjectKey: string, totalShards: number): boolean {

diff --git a/src/flag-evaluation-details-builder.ts b/src/flag-evaluation-details-builder.ts
@@ -49,8 +49,8 @@ export class FlagEvaluationDetailsBuilder {
   private variationValue: IFlagEvaluationDetails['variationValue'] = null;
   private matchedRule: IFlagEvaluationDetails['matchedRule'] = null;
   private matchedAllocation: IFlagEvaluationDetails['matchedAllocation'] = null;
-  private unmatchedAllocations: IFlagEvaluationDetails['unmatchedAllocations'] = [];
-  private unevaluatedAllocations: IFlagEvaluationDetails['unevaluatedAllocations'] = [];
+  private readonly unmatchedAllocations: IFlagEvaluationDetails['unmatchedAllocations'] = [];
+  private readonly unevaluatedAllocations: IFlagEvaluationDetails['unevaluatedAllocations'] = [];
 
   constructor(
     private readonly environmentName: string,
@@ -61,31 +61,15 @@ export class FlagEvaluationDetailsBuilder {
     this.setNone();
   }
 
-  setNone = (): FlagEvaluationDetailsBuilder => {
-    this.variationKey = null;
-    this.variationValue = null;
-    this.matchedRule = null;
-    this.matchedAllocation = null;
-    this.unmatchedAllocations = [];
-    this.unevaluatedAllocations = this.allocations.map(
-      (allocation, i): AllocationEvaluation => ({
-        key: allocation.key,
-        allocationEvaluationCode: AllocationEvaluationCode.UNEVALUATED,
-        orderPosition: i + 1,
-      }),
-    );
-    return this;
+  addUnmatchedAllocation = (allocationEvaluation: AllocationEvaluation) => {
+    this.unmatchedAllocations.push(allocationEvaluation);
   };
 
-  setNoMatchFound = (
-    unmatchedAllocations: Array<AllocationEvaluation> = [],
-  ): FlagEvaluationDetailsBuilder => {
+  setNone = (): FlagEvaluationDetailsBuilder => {
     this.variationKey = null;
     this.variationValue = null;
-    this.matchedAllocation = null;
     this.matchedRule = null;
-    this.unmatchedAllocations = unmatchedAllocations;
-    this.unevaluatedAllocations = [];
+    this.matchedAllocation = null;
     return this;
   };
 
@@ -94,7 +78,6 @@ export class FlagEvaluationDetailsBuilder {
     variation: Variation,
     allocation: Allocation,
     matchedRule: Rule | null,
-    unmatchedAllocations: Array<AllocationEvaluation>,
     expectedVariationType: VariationType | undefined,
   ): FlagEvaluationDetailsBuilder => {
     this.variationKey = variation.key;
@@ -110,17 +93,6 @@ export class FlagEvaluationDetailsBuilder {
       allocationEvaluationCode: AllocationEvaluationCode.MATCH,
       orderPosition: indexPosition + 1, // orderPosition is 1-indexed to match UI
     };
-    this.unmatchedAllocations = unmatchedAllocations;
-    const unevaluatedStartIndex = indexPosition + 1;
-    const unevaluatedStartOrderPosition = unevaluatedStartIndex + 1; // orderPosition is 1-indexed to match UI
-    this.unevaluatedAllocations = this.allocations.slice(unevaluatedStartIndex).map(
-      (allocation, i) =>
-        ({
-          key: allocation.key,
-          allocationEvaluationCode: AllocationEvaluationCode.UNEVALUATED,
-          orderPosition: unevaluatedStartOrderPosition + i,
-        } as AllocationEvaluation),
-    );
     return this;
   };
 
@@ -145,6 +117,32 @@ export class FlagEvaluationDetailsBuilder {
     matchedRule: this.matchedRule,
     matchedAllocation: this.matchedAllocation,
     unmatchedAllocations: this.unmatchedAllocations,
-    unevaluatedAllocations: this.unevaluatedAllocations,
+    unevaluatedAllocations: this.calculateUnevaluatedAllocations(),
   });
+
+  gracefulBuild = (
+    flagEvaluationCode: FlagEvaluationCode,
+    flagEvaluationDescription: string,
+  ): IFlagEvaluationDetails | null => {
+    try {
+      return this.build(flagEvaluationCode, flagEvaluationDescription);
+    } catch (err) {
+      return null;
+    }
+  };
+
+  private calculateUnevaluatedAllocations = (): Array<AllocationEvaluation> => {
+    const unevaluatedStartIndex = this.matchedAllocation
+      ? this.unmatchedAllocations.length + 1
+      : this.unmatchedAllocations.length;
+    const unevaluatedStartOrderPosition = unevaluatedStartIndex + 1; // orderPosition is 1-indexed to match UI
+    return this.allocations.slice(unevaluatedStartIndex).map(
+      (allocation, i) =>
+        ({
+          key: allocation.key,
+          allocationEvaluationCode: AllocationEvaluationCode.UNEVALUATED,
+          orderPosition: unevaluatedStartOrderPosition + i,
+        } as AllocationEvaluation),
+    );
+  };
 }
diff --git a/src/flag-evaluation-error.ts b/src/flag-evaluation-error.ts
@@ -0,0 +1,5 @@
+import { IFlagEvaluationDetails } from './flag-evaluation-details-builder';
+
+export class FlagEvaluationError extends Error {
+  flagEvaluationDetails: IFlagEvaluationDetails | undefined;
+}