// Copyright 2019 TiKV Project Authors. Licensed under Apache-2.0.
#[cfg(feature = "protobuf")]
mod pb;
mod text;
#[cfg(feature = "protobuf")]
pub use self::pb::{ProtobufEncoder, PROTOBUF_FORMAT};
pub use self::text::{TextEncoder, TEXT_FORMAT};
use std::io::Write;
use crate::errors::{Error, Result};
use crate::proto::MetricFamily;
/// An interface for encoding metric families into an underlying wire protocol.
pub trait Encoder {
/// `encode` converts a slice of MetricFamily proto messages into target
/// format and writes the resulting lines to `writer`. This function does not
/// perform checks on the content of the metrics and label names,
/// i.e. invalid metrics or label names will result in invalid text format
/// output.
fn encode<W: Write>(&self, mfs: &[MetricFamily], writer: &mut W) -> Result<()>;
/// `format_type` returns target format.
fn format_type(&self) -> &str;
}
fn check_metric_family(mf: &MetricFamily) -> Result<()> {
if mf.get_metric().is_empty() {
return Err(Error::Msg(format!("MetricFamily has no metrics: {:?}", mf)));
}
if mf.get_name().is_empty() {
return Err(Error::Msg(format!("MetricFamily has no name: {:?}", mf)));
}
Ok(())
}
#[cfg(test)]
mod tests {
use super::*;
use crate::counter::CounterVec;
use crate::encoder::Encoder;
use crate::metrics::Collector;
use crate::metrics::Opts;
#[test]
#[cfg(feature = "protobuf")]
fn test_bad_proto_metrics() {
let mut writer = Vec::<u8>::new();
let pb_encoder = ProtobufEncoder::new();
let cv = CounterVec::new(
Opts::new("test_counter_vec", "help information"),
&["labelname"],
)
.unwrap();
// Empty metrics
let mfs = cv.collect();
check_metric_family(&mfs[0]).unwrap_err();
pb_encoder.encode(&mfs, &mut writer).unwrap_err();
assert_eq!(writer.len(), 0);
// Add a sub metric
cv.with_label_values(&["foo"]).inc();
let mut mfs = cv.collect();
// Empty name
(&mut mfs[0]).clear_name();
check_metric_family(&mfs[0]).unwrap_err();
pb_encoder.encode(&mfs, &mut writer).unwrap_err();
assert_eq!(writer.len(), 0);
}
#[test]
fn test_bad_text_metrics() {
let mut writer = Vec::<u8>::new();
let text_encoder = TextEncoder::new();
let cv = CounterVec::new(
Opts::new("test_counter_vec", "help information"),
&["labelname"],
)
.unwrap();
// Empty metrics
let mfs = cv.collect();
check_metric_family(&mfs[0]).unwrap_err();
text_encoder.encode(&mfs, &mut writer).unwrap_err();
assert_eq!(writer.len(), 0);
// Add a sub metric
cv.with_label_values(&["foo"]).inc();
let mut mfs = cv.collect();
// Empty name
(&mut mfs[0]).clear_name();
check_metric_family(&mfs[0]).unwrap_err();
text_encoder.encode(&mfs, &mut writer).unwrap_err();
assert_eq!(writer.len(), 0);
}
}