refactor(dynamodb): split 7,935-line service.rs into sub-modules

[vieiralucas]

Summary

• Splits monolithic 7,935-line service.rs into 7 focused sub-modules
• mod.rs (4,829 lines): struct, dispatch, expression evaluation engine, helpers, tests
• tables.rs (1,378 lines): table CRUD, TTL, tags, backups
• batch.rs (564 lines): batch/transact operations, PartiQL
• items.rs (407 lines): PutItem, GetItem, DeleteItem, UpdateItem
• queries.rs (328 lines): Query, Scan
• streams.rs (299 lines): endpoints, limits, Kinesis destinations
• global_tables.rs (281 lines): global table operations

Test plan

• cargo clippy --workspace --all-targets -- -D warnings passes clean
• All 92 DynamoDB unit tests pass
• CI passes
• Cubic review passes

---

Summary by cubic

Split the monolithic DynamoDB service.rs into focused sub-modules to improve readability, maintainability, and testability. No behavior changes; APIs stay the same.

• Refactors
  • Added modules: mod.rs (core struct/dispatch/expr eval/helpers/tests), tables.rs (table CRUD, TTL, tags, backups), batch.rs (batch/transact + PartiQL), items.rs (Put/Get/Delete/Update), queries.rs (Query/Scan), streams.rs (endpoints/limits/Kinesis destinations), global_tables.rs (global tables).
  • Kept shared helpers and the expression engine in mod.rs.
  • cargo clippy --workspace --all-targets -- -D warnings passes; all DynamoDB unit tests pass.

^{Written for commit 2a32f62. Summary will update on new commits.}

[cubic-dev-ai]

4 issues found across 7 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="crates/fakecloud-dynamodb/src/service/streams.rs">

<violation number="1" location="crates/fakecloud-dynamodb/src/service/streams.rs:103">
P1: `update_kinesis_streaming_destination` returns a hard-coded ACTIVE status even when the destination is missing or currently disabled.</violation>
</file>

<file name="crates/fakecloud-dynamodb/src/service/global_tables.rs">

<violation number="1" location="crates/fakecloud-dynamodb/src/service/global_tables.rs:31">
P1: `ReplicationGroup` members without `RegionName` are silently ignored, so invalid input can create a table with an incomplete replica set instead of failing validation.</violation>

<violation number="2" location="crates/fakecloud-dynamodb/src/service/global_tables.rs:155">
P2: `ExclusiveStartGlobalTableName` is validated but ignored, so pagination requests return incorrect slices.</violation>

<violation number="3" location="crates/fakecloud-dynamodb/src/service/global_tables.rs:165">
P2: Listing uses unordered `HashMap::values()` with `take(limit)`, producing nondeterministic result order and unstable pagination.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[cubic-dev-ai]

P1: update_kinesis_streaming_destination returns a hard-coded ACTIVE status even when the destination is missing or currently disabled.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At crates/fakecloud-dynamodb/src/service/streams.rs, line 103:

<comment>`update_kinesis_streaming_destination` returns a hard-coded ACTIVE status even when the destination is missing or currently disabled.</comment>

<file context>
@@ -0,0 +1,299 @@
+        Self::ok_json(json!({
+            "TableName": table_name,
+            "StreamArn": stream_arn,
+            "DestinationStatus": "ACTIVE",
+            "EnableKinesisStreamingConfiguration": {
+                "ApproximateCreationDateTimePrecision": precision
</file context>

[cubic-dev-ai]

P1: ReplicationGroup members without RegionName are silently ignored, so invalid input can create a table with an incomplete replica set instead of failing validation.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At crates/fakecloud-dynamodb/src/service/global_tables.rs, line 31:

<comment>`ReplicationGroup` members without `RegionName` are silently ignored, so invalid input can create a table with an incomplete replica set instead of failing validation.</comment>

<file context>
@@ -0,0 +1,281 @@
+                )
+            })?
+            .iter()
+            .filter_map(|r| {
+                r["RegionName"].as_str().map(|rn| ReplicaDescription {
+                    region_name: rn.to_string(),
</file context>

[cubic-dev-ai]

P2: Listing uses unordered HashMap::values() with take(limit), producing nondeterministic result order and unstable pagination.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At crates/fakecloud-dynamodb/src/service/global_tables.rs, line 165:

<comment>Listing uses unordered `HashMap::values()` with `take(limit)`, producing nondeterministic result order and unstable pagination.</comment>

<file context>
@@ -0,0 +1,281 @@
+        let state = self.state.read();
+        let tables: Vec<Value> = state
+            .global_tables
+            .values()
+            .take(limit)
+            .map(|gt| {
</file context>

[cubic-dev-ai]

P2: ExclusiveStartGlobalTableName is validated but ignored, so pagination requests return incorrect slices.

Prompt for AI agents

Check if this issue is valid — if so, understand the root cause and fix it. At crates/fakecloud-dynamodb/src/service/global_tables.rs, line 155:

<comment>`ExclusiveStartGlobalTableName` is validated but ignored, so pagination requests return incorrect slices.</comment>

<file context>
@@ -0,0 +1,281 @@
+        let body = Self::parse_body(req)?;
+        validate_optional_string_length(
+            "exclusiveStartGlobalTableName",
+            body["ExclusiveStartGlobalTableName"].as_str(),
+            3,
+            255,
</file context>