feat(eventbridge): add InputTransformer support and S3 event notifications by rpalcolea · Pull Request #152 · hectorvent/floci

rpalcolea · 2026-04-01T04:11:59Z

Summary

This PR adds two EventBridge features to floci:

InputTransformer on rule targets — events can be reshaped before delivery so targets receive only the fields they need instead of the full event envelope.
S3 → EventBridge notifications — S3 buckets can forward object lifecycle events to the EventBridge default bus, enabling event-driven architectures that react to object changes without polling.

Feature 1: EventBridge InputTransformer

Overview

AWS EventBridge lets you attach an InputTransformer to a rule target so that events are reshaped before delivery. Instead of forwarding the full event envelope to a target (SQS, SNS, Lambda), you extract only the fields you care about and produce a custom payload.

How It Works

An InputTransformer has two parts:

InputPathsMap — a map of variable names to JSONPath expressions. Each path is evaluated against the incoming event JSON and the result is bound to the variable name.
InputTemplate — a string template with <varName> placeholders. After all variables are resolved, placeholders are replaced with their extracted values before the payload is delivered.

If a JSONPath expression matches a missing or null field, the placeholder is replaced with an empty string. If InputTemplate is absent, the full event JSON is delivered as-is.

Example

Given an incoming event:

{
  "source": "my.app",
  "detail-type": "OrderPlaced",
  "detail": { "orderId": "123", "amount": 99.99 }
}

With this transformer configured on the target:

{
  "InputPathsMap": {
    "src": "$.source",
    "detail": "$.detail-type"
  },
  "InputTemplate": "{\"source\":\"<src>\",\"type\":\"<detail>\"}"
}

The target receives:

{"source":"my.app","type":"OrderPlaced"}

The raw orderId and amount fields are never forwarded.

API

PutTargets

Include InputTransformer alongside the target Id and Arn:

{
  "Rule": "my-rule",
  "Targets": [{
    "Id": "1",
    "Arn": "arn:aws:sqs:us-east-1:000000000000:my-queue",
    "InputTransformer": {
      "InputPathsMap": {
        "src": "$.source",
        "detail": "$.detail-type"
      },
      "InputTemplate": "{\"source\":\"<src>\",\"type\":\"<detail>\"}"
    }
  }]
}

ListTargetsByRule

The InputTransformer is returned as-is when listing targets:

{
  "Targets": [{
    "Id": "1",
    "Arn": "arn:aws:sqs:...",
    "InputTransformer": {
      "InputPathsMap": { "src": "$.source" },
      "InputTemplate": "{\"source\":\"<src>\"}"
    }
  }]
}

JSONPath Support

Paths use dot notation starting with $:

Path	Resolves
`$.source`	top-level `source` field
`$.detail.bucket.name`	nested field
`$.detail.size`	non-string value returned as raw JSON (e.g. `42`)
`$.missing.field`	returns empty string in template

Feature 2: S3 → EventBridge Notifications

Overview

AWS S3 supports forwarding bucket event notifications directly to EventBridge. When enabled, every object creation and deletion fires an event to the EventBridge default bus with source=aws.s3. Rules on the default bus can then match and route these events to any supported target.

This is an alternative to the traditional SQS/SNS notification approach — it decouples S3 from specific consumers and lets EventBridge rules handle fan-out, filtering, and transformation.

How It Works

Set <EventBridgeConfiguration/> in the bucket's notification configuration. No ARN is required — all matching events go to the default bus automatically. EventBridge rules with "source": ["aws.s3"] in their event pattern will match and route them.

Events are fired for:

s3:ObjectCreated:Put → detail-type: Object Created
s3:ObjectCreated:Copy → detail-type: Object Created
s3:ObjectCreated:CompleteMultipartUpload → detail-type: Object Created
s3:ObjectRemoved:Delete → detail-type: Object Deleted
s3:ObjectRemoved:DeleteMarkerCreated → detail-type: Object Deleted

Event Shape

{
  "version": "0",
  "id": "<uuid>",
  "source": "aws.s3",
  "detail-type": "Object Created",
  "account": "000000000000",
  "time": "2026-04-01T00:00:00Z",
  "region": "us-east-1",
  "resources": [],
  "detail": {
    "version": "0",
    "bucket": { "name": "my-bucket" },
    "object": { "key": "uploads/photo.jpg", "size": 4096, "etag": "abc123" },
    "request-id": "<uuid>",
    "requester": "aws:emulator",
    "source-ip-address": "127.0.0.1",
    "reason": "ObjectCreated:Put"
  }
}

API

Enable EventBridge notifications

<NotificationConfiguration>
  <EventBridgeConfiguration/>
</NotificationConfiguration>

Disable EventBridge notifications

<NotificationConfiguration/>

Example EventBridge rule matching S3 events

{
  "Name": "s3-object-created-rule",
  "EventPattern": "{\"source\":[\"aws.s3\"],\"detail-type\":[\"Object Created\"]}",
  "State": "ENABLED"
}

Support InputPathsMap + InputTemplate on EventBridge targets so events can be projected to a subset of fields before delivery to SQS/SNS/Lambda. - Add InputTransformer model with inputPathsMap and inputTemplate fields - Parse and serialize InputTransformer in PutTargets / ListTargetsByRule - Apply transformer in invokeTarget: extract JSONPath variables, substitute <varName> placeholders in the template - Use Jackson JsonPointer for JSONPath resolution ($.a.b.c → /a/b/c) - Add unit tests for extractJsonPath and applyInputTransformer edge cases - Add integration tests covering full put/list/deliver/transform flow Fixes hectorvent#140

Copilot

Pull request overview

Adds AWS EventBridge InputTransformer support on rule targets so events can be reshaped before delivery to targets (SQS/SNS/Lambda), and validates behavior via new unit + integration tests.

Changes:

Introduces InputTransformer model and adds it to Target.
Parses/returns InputTransformer in PutTargets / ListTargetsByRule, and applies transformations during target invocation.
Adds unit tests for JSONPath extraction / template substitution and a new end-to-end integration test covering SQS delivery with and without transformers.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
`src/main/java/io/github/hectorvent/floci/services/eventbridge/EventBridgeService.java`	Applies `InputTransformer` when delivering events to targets; adds JSONPath extraction and template substitution.
`src/main/java/io/github/hectorvent/floci/services/eventbridge/EventBridgeHandler.java`	Parses `InputTransformer` from `PutTargets` requests and includes it in `ListTargetsByRule` responses.
`src/main/java/io/github/hectorvent/floci/services/eventbridge/model/Target.java`	Extends target model to store `InputTransformer`.
`src/main/java/io/github/hectorvent/floci/services/eventbridge/model/InputTransformer.java`	New model representing `InputPathsMap` + `InputTemplate`.
`src/test/java/io/github/hectorvent/floci/services/eventbridge/EventBridgeServiceTest.java`	Adds unit tests for JSONPath extraction and transformer substitution rules.
`src/test/java/io/github/hectorvent/floci/services/eventbridge/EventBridgeIntegrationTest.java`	New Quarkus integration test validating transformer persistence and transformed payload delivery to SQS.

Copilot · 2026-04-01T04:16:46Z

src/test/java/io/github/hectorvent/floci/services/eventbridge/EventBridgeIntegrationTest.java

+        assert transformedBody != null : "Expected a message in the transformer queue";
+        assert transformedBody.contains("my.app") : "Expected source my.app in: " + transformedBody;
+        assert transformedBody.contains("OrderPlaced") : "Expected type OrderPlaced in: " + transformedBody;
+        assert !transformedBody.contains("orderId") : "Expected raw orderId to be absent in: " + transformedBody;
+    }


The test uses Java assert statements, which are disabled unless the JVM is started with -ea, so these checks may be skipped in CI and the test could pass even when the transformer output is wrong. Use JUnit assertions (e.g., Assertions.assertNotNull / assertTrue / assertFalse) so failures are always enforced.

@rpalcolea please address this comment review.

Copilot · 2026-04-01T04:16:46Z

src/test/java/io/github/hectorvent/floci/services/eventbridge/EventBridgeIntegrationTest.java

+            .formParam("Action", "ReceiveMessage")
+            .formParam("QueueUrl", transformerQueueUrl)
+            .formParam("MaxNumberOfMessages", "10")
+        .when()
+            .post("/");


This “drain” step calls ReceiveMessage but does not delete messages (or purge the queue). Since SQS receives only hide messages for the visibility timeout, the previously received message can reappear later and make this test flaky. Consider using PurgeQueue for the test queue or explicitly DeleteMessage for any receipt handles returned by ReceiveMessage.

Suggested change

.formParam("Action", "ReceiveMessage")

.formParam("QueueUrl", transformerQueueUrl)

.formParam("MaxNumberOfMessages", "10")

.when()

.post("/");

.formParam("Action", "PurgeQueue")

.formParam("QueueUrl", transformerQueueUrl)

.when()

.post("/")

.then()

.statusCode(200);

Copilot · 2026-04-01T04:16:46Z

src/main/java/io/github/hectorvent/floci/services/eventbridge/EventBridgeService.java

+    String applyInputTransformer(InputTransformer transformer, String eventJson) {
+        String template = transformer.getInputTemplate();
+        if (template == null) {
+            return eventJson;
+        }
+        String result = template;
+        for (var e : transformer.getInputPathsMap().entrySet()) {
+            String value = extractJsonPath(e.getValue(), eventJson);
+            result = result.replace("<" + e.getKey() + ">", value != null ? value : "");
+        }


applyInputTransformer() calls extractJsonPath() for each entry, and extractJsonPath() reparses eventJson with objectMapper.readTree(...) every time. For transformers with multiple variables and/or large events, this adds significant overhead per target invocation. Parse the event JSON once (e.g., to a JsonNode) and reuse it for all path extractions.

@rpalcolea please take a look to this performance improvement.

Copilot · 2026-04-01T04:16:46Z

src/main/java/io/github/hectorvent/floci/services/eventbridge/EventBridgeService.java

+                case String a when a.contains(":lambda:") || a.contains(":function:") -> {
+                    String fnName = a.substring(a.lastIndexOf(':') + 1);
+                    lambdaService.invoke(extractRegionFromArn(a, region), fnName, payload.getBytes(), InvocationType.Event);
+                    LOG.debugv("EventBridge delivered to Lambda: {0}", a);


payload.getBytes() uses the platform default charset, which can vary by environment. For consistent AWS-compatible behavior (JSON is UTF-8), encode explicitly with UTF-8 when invoking Lambda.

This one also need to be addressed, please

Copilot · 2026-04-01T04:16:46Z

src/main/java/io/github/hectorvent/floci/services/eventbridge/EventBridgeService.java

+        String payload;
+        if (target.getInput() != null) {
+            payload = target.getInput();
+        } else if (target.getInputTransformer() != null) {
+            payload = applyInputTransformer(target.getInputTransformer(), eventJson);
+        } else {
+            payload = eventJson;


If a target is configured with both Input and InputTransformer, this logic silently prefers Input and ignores the transformer. That can be surprising for callers and makes the API ambiguous; consider validating that only one of Input, InputPath, or InputTransformer is set and returning a ValidationException when multiple are provided.

@rpalcolea could you investigate what is the AWS behavior in this scenario?

hectorvent · 2026-04-01T05:57:48Z

Hi @rpalcolea,

Thanks for the PR. Could you get a PR for this new feature in the floci-* repo, please?

When a bucket has <EventBridgeConfiguration/> in its notification config, every s3:ObjectCreated and s3:ObjectRemoved event is also sent to the EventBridge default bus with source=aws.s3 and a CloudTrail-style detail payload containing bucket name, object key, size, and etag. - Add eventBridgeEnabled flag to NotificationConfiguration - Parse <EventBridgeConfiguration/> in S3Controller - Inject EventBridgeService into S3Service and call putEvents in fireNotifications - Add integration tests covering enable/disable and event delivery for put and delete operations Fixes hectorvent#140

Copilot AI review requested due to automatic review settings April 1, 2026 04:12

Copilot started reviewing on behalf of rpalcolea April 1, 2026 04:12 View session

Copilot AI reviewed Apr 1, 2026

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hectorvent approved these changes Apr 1, 2026

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hectorvent added the event-bridge label Apr 1, 2026

hectorvent added the waiting-contributor label Apr 1, 2026

rpalcolea changed the title ~~feat(eventbridge): add InputTransformer support for rule targets~~ feat(eventbridge): add InputTransformer support and S3 event notifications Apr 1, 2026

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feat(eventbridge): add InputTransformer support and S3 event notifications#152

feat(eventbridge): add InputTransformer support and S3 event notifications#152
rpalcolea wants to merge 2 commits intohectorvent:mainfrom
rpalcolea:feat/eventbridge-input-transformer

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Summary

Feature 1: EventBridge InputTransformer

Overview

How It Works

Example

API

PutTargets

ListTargetsByRule

JSONPath Support

Feature 2: S3 → EventBridge Notifications

Overview

How It Works

Event Shape

API

Enable EventBridge notifications

Disable EventBridge notifications

Example EventBridge rule matching S3 events

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rpalcolea commented Apr 1, 2026 •

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hectorvent commented Apr 1, 2026 •

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