feat: add gRPC transport with Vector wire protocol compatibility

Replace zenoh transport with tonic-based gRPC transport supporting both
DFE native protocol and Vector v2 PushEvents wire compatibility.

Author: Derek

Cargo.toml

@@ -63,8 +63,9 @@ config-postgres = ["config", "sqlx", "tokio", "serde_json"]
 transport = ["tokio", "serde_json", "rmp-serde", "chrono", "async-trait"]
 transport-memory = ["transport"]
 transport-kafka = ["transport", "rdkafka"]
-transport-zenoh = ["transport", "zenoh"]
-transport-all = ["transport-memory", "transport-kafka", "transport-zenoh"]
+transport-grpc = ["transport", "dep:tonic", "dep:prost", "dep:prost-types", "dep:tonic-build", "dep:prost-build"]
+transport-grpc-vector-compat = ["transport-grpc"]
+transport-all = ["transport-memory", "transport-kafka", "transport-grpc"]
 
 # Secrets management
 secrets = ["tokio", "serde_json", "async-trait", "parking_lot", "base64", "dirs", "tracing"]
@@ -73,7 +74,7 @@ secrets-aws = ["secrets", "aws-config", "aws-sdk-secretsmanager"]
 secrets-all = ["secrets-vault", "secrets-aws"]
 
 # Full feature set
-full = ["config", "config-reload", "logger", "metrics", "otel", "otel-metrics", "env", "runtime", "http", "http-server", "spool", "tiered-sink", "resilience", "database", "cache", "transport-all", "secrets-all", "directory-config", "directory-config-git", "deployment", "version-check"]
+full = ["config", "config-reload", "logger", "metrics", "otel", "otel-metrics", "env", "runtime", "http", "http-server", "spool", "tiered-sink", "resilience", "database", "cache", "transport-all", "transport-grpc-vector-compat", "secrets-all", "directory-config", "directory-config-git", "deployment", "version-check"]
 
 [dependencies]
 # Serialisation (always needed)
@@ -145,8 +146,10 @@ rmp-serde = { version = ">=1.3.1, <2", optional = true }
 # Kafka transport
 rdkafka = { version = ">=0.38.0, <0.39", optional = true }
 
-# Zenoh transport
-zenoh = { version = ">=1.7.2, <2", optional = true }
+# gRPC transport (tonic + prost)
+tonic = { version = ">=0.12, <0.14", features = ["gzip"], optional = true }
+prost = { version = ">=0.13, <0.14", optional = true }
+prost-types = { version = ">=0.13, <0.14", optional = true }
 
 # Spool (disk-backed async queue) - yaque is async-native and maintained
 yaque = { version = ">=0.6.6, <0.7", optional = true }
@@ -173,6 +176,10 @@ vaultrs = { version = ">=0.7, <0.8", optional = true }
 aws-config = { version = ">=1.6, <2", optional = true }
 aws-sdk-secretsmanager = { version = ">=1.72, <2", optional = true }
 
+[build-dependencies]
+tonic-build = { version = ">=0.12, <0.14", optional = true }
+prost-build = { version = ">=0.13, <0.14", optional = true }
+
 [dev-dependencies]
 tokio = { version = ">=1.49.0, <2", features = ["full", "test-util"] }
 tempfile = ">=3.24.0, <4"

build.rs

@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: FSL-1.1-ALv2
+// Copyright (c) 2026 HYPERI PTY LIMITED
+//
+// Protobuf code generation for gRPC transport.
+// Only runs when transport-grpc or transport-grpc-vector-compat features are enabled.
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    // DFE native transport proto
+    #[cfg(feature = "transport-grpc")]
+    {
+        tonic_build::configure()
+            .build_server(true)
+            .build_client(true)
+            .compile_protos(&["proto/dfe/transport/v1/dfe_transport.proto"], &["proto"])?;
+    }
+
+    // Vector wire protocol compat (vendored protos)
+    #[cfg(feature = "transport-grpc-vector-compat")]
+    {
+        // Compile event.proto first (message types only, no services)
+        prost_build::Config::new()
+            .compile_protos(&["proto/vector/event.proto"], &["proto/vector"])?;
+
+        // Compile vector.proto (service + request/response types)
+        // extern_path tells prost the event types live in the sibling module
+        tonic_build::configure()
+            .build_server(true)
+            .build_client(true)
+            .extern_path(".event", "crate::transport::vector_compat::proto::event")
+            .compile_protos(&["proto/vector/vector.proto"], &["proto/vector"])?;
+    }
+
+    Ok(())
+}

proto/dfe/transport/v1/dfe_transport.proto

@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: FSL-1.1-ALv2
+// Copyright (c) 2026 HYPERI PTY LIMITED
+//
+// DFE native transport protocol.
+// Lightweight bulk bytes transfer with format hints.
+
+syntax = "proto3";
+
+package dfe.transport.v1;
+
+// DFE inter-service transport.
+service DfeTransport {
+  // Push a batch of data to the receiver.
+  rpc Push(PushRequest) returns (PushResponse);
+
+  // Health check.
+  rpc HealthCheck(HealthCheckRequest) returns (HealthCheckResponse);
+}
+
+// Data format hint for the receiver.
+enum Format {
+  FORMAT_AUTO = 0;
+  FORMAT_JSON = 1;
+  FORMAT_MSGPACK = 2;
+  FORMAT_ARROW_IPC = 3;
+}
+
+message PushRequest {
+  // Raw payload bytes (JSON lines, MsgPack, or Arrow IPC batch).
+  bytes payload = 1;
+
+  // Format hint so the receiver can skip detection.
+  Format format = 2;
+
+  // Routing metadata (e.g. topic, org_id, source).
+  map<string, string> metadata = 3;
+}
+
+message PushResponse {
+  // Number of events accepted by the receiver.
+  uint64 accepted = 1;
+}
+
+// Serving status.
+enum ServingStatus {
+  SERVING = 0;
+  NOT_SERVING = 1;
+}
+
+message HealthCheckRequest {}
+
+message HealthCheckResponse {
+  ServingStatus status = 1;
+}

proto/vector/event.proto

@@ -0,0 +1,242 @@
+// Vendored from https://github.com/vectordotdev/vector
+// Source: lib/vector-core/proto/event.proto
+// Pinned: 2026-03-02 (stable since 2021, rarely changes)
+
+syntax = "proto3";
+
+package event;
+
+import "google/protobuf/timestamp.proto";
+
+message EventArray {
+  oneof events {
+    LogArray logs = 1;
+    MetricArray metrics = 2;
+    TraceArray traces = 3;
+  }
+}
+
+message LogArray {
+  repeated Log logs = 1;
+}
+
+message MetricArray {
+  repeated Metric metrics = 1;
+}
+
+message TraceArray {
+  repeated Trace traces = 1;
+}
+
+message EventWrapper {
+  oneof event {
+    Log log = 1;
+    Metric metric = 2;
+    Trace trace = 3;
+  }
+}
+
+message Log {
+  // Deprecated, use value instead
+  map<string, Value> fields = 1;
+  Value value = 2;
+  Value metadata = 3 [deprecated = true];
+  Metadata metadata_full = 4;
+}
+
+message Trace {
+  map<string, Value> fields = 1;
+  Value metadata = 2 [deprecated = true];
+  Metadata metadata_full = 3;
+}
+
+message ValueMap {
+  map<string, Value> fields = 1;
+}
+
+message ValueArray {
+  repeated Value items = 1;
+}
+
+enum ValueNull {
+  NULL_VALUE = 0;
+}
+
+message Value {
+  reserved 3;
+  oneof kind {
+    bytes raw_bytes = 1;
+    google.protobuf.Timestamp timestamp = 2;
+    int64 integer = 4;
+    double float = 5;
+    bool boolean = 6;
+    ValueMap map = 7;
+    ValueArray array = 8;
+    ValueNull null = 9;
+  }
+}
+
+message DatadogOriginMetadata {
+  optional uint32 origin_product = 1;
+  optional uint32 origin_category = 2;
+  optional uint32 origin_service = 3;
+}
+
+message Secrets {
+  map<string, string> entries = 1;
+}
+
+message OutputId {
+  string component = 1;
+  optional string port = 2;
+}
+
+message Metadata {
+  Value value = 1;
+  DatadogOriginMetadata datadog_origin_metadata = 2;
+  optional string source_id = 3;
+  optional string source_type = 4;
+  OutputId upstream_id = 5;
+  Secrets secrets = 6;
+  bytes source_event_id = 7;
+}
+
+message Metric {
+  string name = 1;
+  google.protobuf.Timestamp timestamp = 2;
+  map<string, string> tags_v1 = 3;
+  map<string, TagValues> tags_v2 = 20;
+  enum Kind {
+    Incremental = 0;
+    Absolute = 1;
+  }
+  Kind kind = 4;
+  oneof value {
+    Counter counter = 5;
+    Gauge gauge = 6;
+    Set set = 7;
+    Distribution1 distribution1 = 8;
+    AggregatedHistogram1 aggregated_histogram1 = 9;
+    AggregatedSummary1 aggregated_summary1 = 10;
+    Distribution2 distribution2 = 12;
+    AggregatedHistogram2 aggregated_histogram2 = 13;
+    AggregatedSummary2 aggregated_summary2 = 14;
+    Sketch sketch = 15;
+    AggregatedHistogram3 aggregated_histogram3 = 16;
+    AggregatedSummary3 aggregated_summary3 = 17;
+  }
+  string namespace = 11;
+  uint32 interval_ms = 18;
+  Value metadata = 19 [deprecated = true];
+  Metadata metadata_full = 21;
+}
+
+message TagValues {
+  repeated TagValue values = 1;
+}
+
+message TagValue {
+  optional string value = 1;
+}
+
+message Counter {
+  double value = 1;
+}
+
+message Gauge {
+  double value = 1;
+}
+
+message Set {
+  repeated string values = 1;
+}
+
+enum StatisticKind {
+  Histogram = 0;
+  Summary = 1;
+}
+
+message Distribution1 {
+  repeated double values = 1;
+  repeated uint32 sample_rates = 2;
+  StatisticKind statistic = 3;
+}
+
+message Distribution2 {
+  repeated DistributionSample samples = 1;
+  StatisticKind statistic = 2;
+}
+
+message DistributionSample {
+  double value = 1;
+  uint32 rate = 2;
+}
+
+message AggregatedHistogram1 {
+  repeated double buckets = 1;
+  repeated uint32 counts = 2;
+  uint32 count = 3;
+  double sum = 4;
+}
+
+message AggregatedHistogram2 {
+  repeated HistogramBucket buckets = 1;
+  uint32 count = 2;
+  double sum = 3;
+}
+
+message AggregatedHistogram3 {
+  repeated HistogramBucket3 buckets = 1;
+  uint64 count = 2;
+  double sum = 3;
+}
+
+message HistogramBucket {
+  double upper_limit = 1;
+  uint32 count = 2;
+}
+
+message HistogramBucket3 {
+  double upper_limit = 1;
+  uint64 count = 2;
+}
+
+message AggregatedSummary1 {
+  repeated double quantiles = 1;
+  repeated double values = 2;
+  uint32 count = 3;
+  double sum = 4;
+}
+
+message AggregatedSummary2 {
+  repeated SummaryQuantile quantiles = 1;
+  uint32 count = 2;
+  double sum = 3;
+}
+
+message AggregatedSummary3 {
+  repeated SummaryQuantile quantiles = 1;
+  uint64 count = 2;
+  double sum = 3;
+}
+
+message SummaryQuantile {
+  double quantile = 1;
+  double value = 2;
+}
+
+message Sketch {
+  message AgentDDSketch {
+    uint32 count = 1;
+    double min = 2;
+    double max = 3;
+    double sum = 4;
+    double avg = 5;
+    repeated sint32 k = 6;
+    repeated uint32 n = 7;
+  }
+
+  oneof sketch {
+    AgentDDSketch agent_dd_sketch = 1;
+  }
+}