#draft proto2 fails to push into grafana cloud

Cargo.toml

@@ -18,11 +18,11 @@ travis-ci = { repository = "pingcap/rust-prometheus" }
 features = ["nightly"]
 
 [features]
-default = ["protobuf"]
+default = ["protobuf", "gen", "push"]
 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"

proto/proto_model.proto

@@ -15,26 +15,37 @@ syntax = "proto2";
 
 package io.prometheus.client;
 option java_package = "io.prometheus.client";
+option go_package = "github.com/prometheus/client_model/go;io_prometheus_client";
+
+import "google/protobuf/timestamp.proto";
 
 message LabelPair {
   optional string name  = 1;
   optional string value = 2;
 }
 
 enum MetricType {
-  COUNTER    = 0;
-  GAUGE      = 1;
-  SUMMARY    = 2;
-  UNTYPED    = 3;
-  HISTOGRAM  = 4;
+  // COUNTER must use the Metric field "counter".
+  COUNTER = 0;
+  // GAUGE must use the Metric field "gauge".
+  GAUGE = 1;
+  // SUMMARY must use the Metric field "summary".
+  SUMMARY = 2;
+  // UNTYPED must use the Metric field "untyped".
+  UNTYPED = 3;
+  // HISTOGRAM must use the Metric field "histogram".
+  HISTOGRAM = 4;
+  // GAUGE_HISTOGRAM must use the Metric field "histogram".
+  GAUGE_HISTOGRAM = 5;
 }
 
 message Gauge {
   optional double value = 1;
 }
 
 message Counter {
-  optional double value = 1;
+  optional double   value    = 1;
+  optional Exemplar exemplar = 2;
 }
 
 message Quantile {
@@ -53,14 +64,66 @@ message Untyped {
 }
 
 message Histogram {
-  optional uint64 sample_count = 1;
-  optional double sample_sum   = 2;
-  repeated Bucket bucket       = 3; // Ordered in increasing order of upper_bound, +Inf bucket is optional.
+  optional uint64 sample_count       = 1;
+  optional double sample_count_float = 4; // Overrides sample_count if > 0.
+  optional double sample_sum         = 2;
+  // Buckets for the conventional histogram.
+  repeated Bucket bucket             = 3; // Ordered in increasing order of upper_bound, +Inf bucket is optional.
+
+  // Everything below here is for native histograms (also known as sparse histograms).
+  // Native histograms are an experimental feature without stability guarantees.
+
+  // schema defines the bucket schema. Currently, valid numbers are -4 <= n <= 8.
+  // They are all for base-2 bucket schemas, where 1 is a bucket boundary in each case, and
+  // then each power of two is divided into 2^n logarithmic buckets.
+  // Or in other words, each bucket boundary is the previous boundary times 2^(2^-n).
+  // In the future, more bucket schemas may be added using numbers < -4 or > 8.
+  optional sint32 schema           = 5;
+  optional double zero_threshold   = 6; // Breadth of the zero bucket.
+  optional uint64 zero_count       = 7; // Count in zero bucket.
+  optional double zero_count_float = 8; // Overrides sb_zero_count if > 0.
+
+  // Negative buckets for the native histogram.
+  repeated BucketSpan negative_span =  9;
+  // Use either "negative_delta" or "negative_count", the former for
+  // regular histograms with integer counts, the latter for float
+  // histograms.
+  repeated sint64 negative_delta    = 10; // Count delta of each bucket compared to previous one (or to zero for 1st bucket).
+  repeated double negative_count    = 11; // Absolute count of each bucket.
+
+  // Positive buckets for the native histogram.
+  repeated BucketSpan positive_span = 12;
+  // Use either "positive_delta" or "positive_count", the former for
+  // regular histograms with integer counts, the latter for float
+  // histograms.
+  repeated sint64 positive_delta    = 13; // Count delta of each bucket compared to previous one (or to zero for 1st bucket).
+  repeated double positive_count    = 14; // Absolute count of each bucket.
 }
 
+// A Bucket of a conventional histogram, each of which is treated as
+// an individual counter-like time series by Prometheus.
 message Bucket {
-  optional uint64 cumulative_count = 1; // Cumulative in increasing order.
-  optional double upper_bound = 2;      // Inclusive.
+  optional uint64   cumulative_count       = 1; // Cumulative in increasing order.
+  optional double   cumulative_count_float = 4; // Overrides cumulative_count if > 0.
+  optional double   upper_bound            = 2; // Inclusive.
+  optional Exemplar exemplar               = 3;
+}
+
+// A BucketSpan defines a number of consecutive buckets in a native
+// histogram with their offset. Logically, it would be more
+// straightforward to include the bucket counts in the Span. However,
+// the protobuf representation is more compact in the way the data is
+// structured here (with all the buckets in a single array separate
+// from the Spans).
+message BucketSpan {
+  optional sint32 offset = 1; // Gap to previous span, or starting point for 1st span (which can be negative).
+  optional uint32 length = 2; // Length of consecutive buckets.
+}
+
+message Exemplar {
+  repeated LabelPair                 label     = 1;
+  optional double                    value     = 2;
+  optional google.protobuf.Timestamp timestamp = 3; // OpenMetrics-style.
 }
 
 message Metric {
@@ -78,4 +141,4 @@ message MetricFamily {
   optional string     help   = 2;
   optional MetricType type   = 3;
   repeated Metric     metric = 4;
-}
+}