feat(prometheus): add more compression algorithms to Prometheus Remot…

…e Write (vectordotdev#17334)

Resolves vectordotdev#17199

- add Zstd and Gzip support to Prometheus Remote Write
- add a new compression option in the config (Snappy is the default)
- update the documentation

Tested:
- Local build

src/sinks/prometheus/remote_write.rs

@@ -1,3 +1,4 @@
+use std::io::Read;
 use std::sync::Arc;
 use std::task;
 
@@ -123,10 +124,40 @@ pub struct RemoteWriteConfig {
         skip_serializing_if = "crate::serde::skip_serializing_if_default"
     )]
     pub acknowledgements: AcknowledgementsConfig,
+
+    #[configurable(derived)]
+    #[configurable(metadata(docs::advanced))]
+    #[serde(default)]
+    pub compression: Compression,
 }
 
 impl_generate_config_from_default!(RemoteWriteConfig);
 
+/// Supported compression types for Prometheus Remote Write.
+#[configurable_component]
+#[derive(Clone, Copy, Debug, Derivative)]
+#[derivative(Default)]
+#[serde(rename_all = "lowercase")]
+pub enum Compression {
+    /// Snappy.
+    #[derivative(Default)]
+    Snappy,
+
+    /// Gzip.
+    Gzip,
+
+    /// Zstandard.
+    Zstd,
+}
+
+const fn convert_compression_to_content_encoding(compression: Compression) -> &'static str {
+    match compression {
+        Compression::Snappy => "snappy",
+        Compression::Gzip => "gzip",
+        Compression::Zstd => "zstd",
+    }
+}
+
 #[async_trait::async_trait]
 impl SinkConfig for RemoteWriteConfig {
     async fn build(
@@ -181,6 +212,7 @@ impl SinkConfig for RemoteWriteConfig {
             aws_region,
             credentials_provider,
             http_auth,
+            compression: self.compression,
         });
 
         let healthcheck = healthcheck(client.clone(), Arc::clone(&http_request_builder)).boxed();
@@ -190,6 +222,7 @@ impl SinkConfig for RemoteWriteConfig {
             buckets,
             quantiles,
             http_request_builder,
+            compression: self.compression,
         };
 
         let sink = {
@@ -277,6 +310,7 @@ struct RemoteWriteService {
     buckets: Vec<f64>,
     quantiles: Vec<f64>,
     http_request_builder: Arc<HttpRequestBuilder>,
+    compression: Compression,
 }
 
 impl RemoteWriteService {
@@ -312,7 +346,7 @@ impl Service<PartitionInnerBuffer<Vec<Metric>, PartitionKey>> for RemoteWriteSer
     fn call(&mut self, buffer: PartitionInnerBuffer<Vec<Metric>, PartitionKey>) -> Self::Future {
         let (events, key) = buffer.into_parts();
         let body = self.encode_events(events);
-        let body = snap_block(body);
+        let body = compress_block(self.compression, body);
 
         let client = self.client.clone();
         let request_builder = Arc::clone(&self.http_request_builder);
@@ -344,6 +378,7 @@ pub struct HttpRequestBuilder {
     pub aws_region: Option<Region>,
     pub http_auth: Option<Auth>,
     pub credentials_provider: Option<SharedCredentialsProvider>,
+    pub compression: Compression,
 }
 
 impl HttpRequestBuilder {
@@ -353,11 +388,13 @@ impl HttpRequestBuilder {
         body: Vec<u8>,
         tenant_id: Option<String>,
     ) -> Result<Request<hyper::Body>, crate::Error> {
+        let content_encoding = convert_compression_to_content_encoding(self.compression);
+
         let mut builder = http::Request::builder()
             .method(method)
             .uri(self.endpoint.clone())
             .header("X-Prometheus-Remote-Write-Version", "0.1.0")
-            .header("Content-Encoding", "snappy")
+            .header("Content-Encoding", content_encoding)
             .header("Content-Type", "application/x-protobuf");
 
         if let Some(tenant_id) = &tenant_id {
@@ -380,10 +417,22 @@ impl HttpRequestBuilder {
     }
 }
 
-fn snap_block(data: Bytes) -> Vec<u8> {
-    snap::raw::Encoder::new()
-        .compress_vec(&data)
-        .expect("Out of memory")
+fn compress_block(compression: Compression, data: Bytes) -> Vec<u8> {
+    match compression {
+        Compression::Snappy => snap::raw::Encoder::new()
+            .compress_vec(&data)
+            .expect("snap compression failed, please report"),
+        Compression::Gzip => {
+            let mut buf = Vec::new();
+            flate2::read::GzEncoder::new(data.as_ref(), flate2::Compression::default())
+                .read_to_end(&mut buf)
+                .expect("gzip compression failed, please report");
+            buf
+        }
+        Compression::Zstd => {
+            zstd::encode_all(data.as_ref(), 0).expect("zstd compression failed, please report")
+        }
+    }
 }
 
 async fn sign_request(

website/cue/reference/components/sinks/base/prometheus_remote_write.cue

@@ -223,6 +223,18 @@ base: components: sinks: prometheus_remote_write: configuration: {
 			items: type: float: {}
 		}
 	}
+	compression: {
+		description: "Supported compression types for Prometheus Remote Write."
+		required:    false
+		type: string: {
+			default: "snappy"
+			enum: {
+				gzip:   "Gzip."
+				snappy: "Snappy."
+				zstd:   "Zstandard."
+			}
+		}
+	}
 	default_namespace: {
 		description: """
 			The default namespace for any metrics sent.

website/cue/reference/components/sinks/prometheus_remote_write.cue

@@ -100,5 +100,14 @@ components: sinks: prometheus_remote_write: {
 				values for each name, Vector will only send the last value specified.
 				"""
 		}
+		compression_schemes: {
+			title: "Compression schemes"
+			body:  """
+				Officially according to the [Prometheus Remote-Write specification](\(urls.prometheus_remote_write_spec)),
+				the only supported compression scheme is [Snappy](\(urls.snappy)). However,
+				there are a number of other implementations that do support other schemes. Thus
+				Vector also supports using Gzip and Zstd.
+				"""
+		}
 	}
 }

website/cue/reference/urls.cue

@@ -412,6 +412,7 @@ urls: {
 	prometheus_remote_integrations:             "https://prometheus.io/docs/operating/integrations/#remote-endpoints-and-storage"
 	prometheus_remote_write:                    "https://prometheus.io/docs/prometheus/latest/configuration/configuration/#remote_write"
 	prometheus_remote_write_protocol:           "https://docs.google.com/document/d/1LPhVRSFkGNSuU1fBd81ulhsCPR4hkSZyyBj1SZ8fWOM/edit#heading=h.n0d0vphea3fe"
+	prometheus_remote_write_spec:               "https://prometheus.io/docs/concepts/remote_write_spec/#protocol"
 	protobuf:                                   "https://developers.google.com/protocol-buffers"
 	pulsar:                                     "https://pulsar.apache.org/"
 	pulsar_protocol:                            "https://pulsar.apache.org/docs/en/develop-binary-protocol/"