WIP: feat(datadog_metrics sink): switch series v2 endpoint to zstd compression

changelog.d/24956_datadog_metrics_zstd_series_v2.enhancement.md

@@ -0,0 +1,3 @@
+The `datadog_metrics` sink now uses zstd compression when submitting metrics to the Series v2 endpoint (`/api/v2/series`). Series v1 and Sketches continue to use zlib (deflate).
+
+authors: vladimir-dd

distribution/docker/debian/Dockerfile

@@ -16,7 +16,7 @@ LABEL org.opencontainers.image.documentation="https://vector.dev/docs"
 
 # we want the latest versions of these
 # hadolint ignore=DL3008
-RUN apt-get update && apt-get install -y --no-install-recommends ca-certificates tzdata systemd && rm -rf /var/lib/apt/lists/*
+RUN apt-get update && apt-get install -y --no-install-recommends ca-certificates tzdata systemd libsasl2-2 && rm -rf /var/lib/apt/lists/*
 
 COPY --from=builder /usr/bin/vector /usr/bin/vector
 COPY --from=builder /usr/share/vector /usr/share/vector

regression/Dockerfile

@@ -14,7 +14,7 @@ RUN --mount=type=cache,target=/usr/local/cargo/registry \
 # TARGET
 #
 FROM docker.io/debian:trixie-slim@sha256:c85a2732e97694ea77237c61304b3bb410e0e961dd6ee945997a06c788c545bb
-RUN apt-get update && apt-get dist-upgrade -y && apt-get -y --no-install-recommends install zlib1g ca-certificates && rm -rf /var/lib/apt/lists/*
+RUN apt-get update && apt-get dist-upgrade -y && apt-get -y --no-install-recommends install zlib1g ca-certificates libsasl2-2 && rm -rf /var/lib/apt/lists/*
 COPY --from=builder /vector/vector /usr/bin/vector
 RUN mkdir --parents --mode=0777 /var/lib/vector
 

src/sinks/datadog/metrics/config.rs

@@ -87,11 +87,6 @@ impl DatadogMetricsEndpoint {
         }
     }
 
-    // Gets whether or not this is a series endpoint.
-    pub const fn is_series(self) -> bool {
-        matches!(self, Self::Series { .. })
-    }
-
     pub(super) const fn payload_limits(self) -> DatadogMetricsPayloadLimits {
         // from https://docs.datadoghq.com/api/latest/metrics/#submit-metrics
         let (uncompressed, compressed) = match self {
@@ -112,6 +107,32 @@ impl DatadogMetricsEndpoint {
             compressed,
         }
     }
+
+    /// Returns the compression scheme used for this endpoint.
+    pub(super) const fn compression(self) -> DatadogMetricsCompression {
+        match self {
+            Self::Series(SeriesApiVersion::V2) => DatadogMetricsCompression::Zstd,
+            _ => DatadogMetricsCompression::Zlib,
+        }
+    }
+}
+
+/// Selects the compressor for a given Datadog metrics endpoint.
+#[derive(Clone, Copy, Debug)]
+pub(super) enum DatadogMetricsCompression {
+    /// zlib (deflate) — used by Series v1 and Sketches.
+    Zlib,
+    /// zstd — used by Series v2.
+    Zstd,
+}
+
+impl DatadogMetricsCompression {
+    pub(super) const fn content_encoding(self) -> &'static str {
+        match self {
+            Self::Zstd => "zstd",
+            Self::Zlib => "deflate",
+        }
+    }
 }
 
 /// Maps Datadog metric endpoints to their actual URI.
@@ -270,7 +291,7 @@ impl DatadogMetricsConfig {
             endpoint_configuration,
             self.default_namespace.clone(),
             self.series_api_version,
-        )?;
+        );
 
         let protocol = self.get_protocol(dd_common);
         let sink = DatadogMetricsSink::new(