support for grafana cloud which is snappy default and no suffix in url

fixed generics

more clarity on errors

error description return in push

Signed-off-by: Dzmitry Lahoda <dzmitry@lahoda.pro>

Cargo.toml

@@ -22,7 +22,7 @@ default = ["protobuf"]
 gen = ["protobuf-codegen-pure"]
 nightly = ["libc"]
 process = ["libc", "procfs"]
-push = ["reqwest", "libc", "protobuf"]
+push = ["reqwest", "libc", "protobuf", "snap"]
 
 [dependencies]
 cfg-if = "^1.0"
@@ -31,6 +31,7 @@ lazy_static = "^1.4"
 libc = { version = "^0.2", optional = true }
 parking_lot = "^0.12"
 protobuf = { version = "^2.0", optional = true }
+snap = { version = "^1.1", optional = true }
 memchr = "^2.3"
 reqwest = { version = "^0.11", features = ["blocking"], optional = true }
 thiserror = "^1.0"

src/lib.rs

@@ -224,7 +224,7 @@ pub use self::pulling_gauge::PullingGauge;
 #[cfg(feature = "push")]
 pub use self::push::{
     hostname_grouping_key, push_add_collector, push_add_metrics, push_collector, push_metrics,
-    BasicAuthentication,
+    push_raw, BasicAuthentication,
 };
 pub use self::registry::Registry;
 pub use self::registry::{default_registry, gather, register, unregister};

src/push.rs

@@ -173,6 +173,62 @@ fn push<S: BuildHasher>(
     }
 }
 
+/// Pushes snappy compressed data to url as is.
+pub fn push_raw(
+    url: &str,
+    mfs: Vec<proto::MetricFamily>,
+    method: &str,
+    basic_auth: Option<BasicAuthentication>,
+) -> Result<()> {
+    let mut push_url = if url.contains("://") {
+        url.to_owned()
+    } else {
+        format!("http://{}", url)
+    };
+
+    if push_url.ends_with('/') {
+        push_url.pop();
+    }
+
+    let encoder = ProtobufEncoder::new();
+    let mut proto_buf = Vec::new();
+
+    for mf in mfs {
+        // Ignore error, `no metrics` and `no name`.
+        let _ = encoder.encode(&[mf], &mut proto_buf);
+    }
+
+    let buf = snap::raw::Encoder::new()
+        .compress_vec(&proto_buf)
+        .expect("msg");
+
+    let mut builder = HTTP_CLIENT
+        .request(
+            Method::from_str(method).unwrap(),
+            Url::from_str(&push_url).unwrap(),
+        )
+        .header(CONTENT_TYPE, encoder.format_type())
+        .header("Content-Encoding", "snappy")
+        .body(buf);
+
+    if let Some(BasicAuthentication { username, password }) = basic_auth {
+        builder = builder.basic_auth(username, Some(password));
+    }
+
+    let response = builder.send().map_err(|e| Error::Msg(format!("{}", e)))?;
+
+    match response.status() {
+        StatusCode::ACCEPTED => Ok(()),
+        StatusCode::OK => Ok(()),
+        _ => Err(Error::Msg(format!(
+            "unexpected status code {} while pushing to {} {}",
+            response.status(),
+            push_url,
+            response.text().map(|text| format!("with body `{}`", text)).unwrap_or_default()
+        ))),
+    }
+}
+
 fn push_from_collector<S: BuildHasher>(
     job: &str,
     grouping: HashMap<String, String, S>,