v0.9.0

CHANGES.md

@@ -1,6 +1,14 @@
 # Latest changes + history
 
-## version 0.8.0 ("SUCH REJOICING")
+## version 0.9.0
+- Abandon custom Result type and error module in favor 
+  of io::Result usage across all API. (Based on @rtyler's comment in #80)
+- Update all dependencies to latest versions
+- Move Void module to output (internal change)
+- Examples no longer declare `extern crate dipstick;`  
+
+## version 0.8.0 - ("SUCH REJOICING")
+- THIS VERSION HAS BEEN YANKED - API broke (again) for 0.9.0 and 0.8.0 hadn't been out long enough.
 - Abandon non-threadsafe "Output"s in exchange for a simpler, more consistent API.   
   Everything is now threadsafe and thus all "Output" have been promoted to Inputs.
   No significant performance loss was observed (using parking_lot locks). 

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "dipstick"
-version = "0.8.0"
+version = "0.9.0"
 authors = ["Francis Lalonde <fralalonde@gmail.com>"]
 
 description = """A fast, all-purpose metrics library decoupling instrumentation from reporting backends.
@@ -24,16 +24,16 @@ lazy_static = "1"
 atomic_refcell = "0.1"
 skeptic = { version = "0.13", optional = true }
 num = { version = "0.2", default-features = false }
-crossbeam-channel = { version = "0.3", optional = true }
-parking_lot = { version = "0.9", optional = true }
+crossbeam-channel = { version = "0.4", optional = true }
+parking_lot = { version = "0.10", optional = true }
 
 # FIXME required only for random seed for sampling
 time = "0.1"
 
-minreq = { version = "1.0.0" }
+minreq = { version = "2" }
 
 # optional dep for standalone http pull metrics
-tiny_http = { version = "0.6", optional = true }
+tiny_http = { version = "0.7", optional = true }
 
 [build-dependencies]
 skeptic = { version = "0.13", optional = true }

HANDBOOK.md

@@ -53,7 +53,6 @@ Timers measure an operation's duration.
 Timers can be used in code with the `time!` macro,  wrap around a closure or with explicit calls to `start()` and `stop()`.
 
 ```rust
-extern crate dipstick;
 use dipstick::*;
 fn main() {
     let metrics = Stream::write_to_stdout().metrics();
@@ -90,7 +89,6 @@ Compared to counters:
    rather than min/max observed individual values. 
    
 ```rust
-extern crate dipstick;
 use dipstick::*;
 
 fn main() {
@@ -110,7 +108,6 @@ As such, a gauge's aggregated statistics are simply the mean, max and min values
 Values can be observed for gauges at any moment, like any other metric.    
 
 ```rust
-extern crate dipstick;
 use dipstick::*;
 
 fn main() {
@@ -125,7 +122,6 @@ The observation of values for any metric can be triggered on schedule or upon pu
 
 This mechanism can be used for automatic reporting of gauge values:
 ```rust
-extern crate dipstick;
 use dipstick::*;
 use std::time::{Duration, Instant};
 
@@ -151,7 +147,6 @@ Observations triggered `on_flush` take place _before_  metrics are published, al
 
 Scheduling could also be used to setup a "heartbeat" metric:
 ```rust
-extern crate dipstick;
 use dipstick::*;
 use std::time::{Duration};
 
@@ -182,7 +177,6 @@ Names are opaque to the application and are used only to identify the metrics up
 Names may be prepended with a application-namespace shared across all backends.
 
 ```rust
-extern crate dipstick;
 use dipstick::*;
 fn main() {   
     let stdout = Stream::write_to_stdout();
@@ -233,7 +227,6 @@ Notes about labels:
 Metric inputs are usually setup statically upon application startup.
 
 ```rust
-extern crate dipstick;
 use dipstick::*;
 
 metrics!("my_app" => {
@@ -254,7 +247,6 @@ If necessary, metrics can also be defined "dynamically".
 This is more flexible but has a higher runtime cost, which may be alleviated with the optional caching mechanism.
 
 ```rust
-extern crate dipstick;
 use dipstick::*;
 fn main() {
     let user_name = "john_day";
@@ -303,7 +295,6 @@ Some outputs such as statsd also have the ability to sample metrics values.
 If enabled, sampling is done using pcg32, a fast random algorithm with reasonable entropy.
 
 ```rust
-extern crate dipstick;
 use dipstick::*;
 fn main() {
     let _app_metrics = Statsd::send_to("localhost:8125").expect("connected")

README.md

@@ -41,7 +41,6 @@ These are all best done by downstream timeseries visualization and monitoring to
 Here's a basic aggregating & auto-publish counter metric:
 
 ```rust
-extern crate dipstick;
 use dipstick::*;
 
 fn main() {
@@ -56,7 +55,6 @@ fn main() {
 Persistent apps wanting to declare static metrics will prefer using the `metrics!` macro:
 
 ```rust
-extern crate dipstick;
 use dipstick::*;
 
 metrics! { METRICS = "my_app" => {

examples/async_queue.rs

@@ -1,7 +1,5 @@
 //! A sample application asynchronously printing metrics to stdout.
 
-extern crate dipstick;
-
 use dipstick::{Input, InputScope, QueuedInput, Stream};
 use std::thread;
 use std::thread::sleep;

examples/basics.rs

@@ -1,12 +1,10 @@
 //! An app demonstrating the basics of the metrics front-end.
 //! Defines metrics of each kind and use them to print values to the console in multiple ways.
 
-extern crate dipstick;
-
-use dipstick::*;
 use std::io;
 use std::thread::sleep;
 use std::time::Duration;
+use dipstick::{Stream, Input, InputScope, Prefixed, time};
 
 fn main() {
     // for this demo, print metric values to the console

examples/bench_bucket.rs

@@ -1,13 +1,11 @@
 //! A sample application asynchronously printing metrics to stdout.
 
-extern crate dipstick;
-
-use dipstick::*;
 use std::env::args;
 use std::str::FromStr;
 use std::thread;
 use std::thread::sleep;
 use std::time::Duration;
+use dipstick::{AtomicBucket, stats_all, InputScope, Stream, Input};
 
 fn main() {
     let bucket = AtomicBucket::new();

examples/bench_bucket_proxy.rs

@@ -1,13 +1,11 @@
 //! A sample application asynchronously printing metrics to stdout.
 
-extern crate dipstick;
-
-use dipstick::*;
 use std::env::args;
 use std::str::FromStr;
 use std::thread;
 use std::thread::sleep;
 use std::time::Duration;
+use dipstick::{Proxy, AtomicBucket, InputScope, Stream, Input};
 
 fn main() {
     let event = Proxy::default().marker("a");

examples/bench_queue.rs

@@ -1,16 +1,15 @@
 //! A sample application asynchronously printing metrics to stdout.
 
-extern crate dipstick;
-
-use dipstick::*;
 use std::env::args;
 use std::str::FromStr;
 use std::thread;
 use std::thread::sleep;
 use std::time::Duration;
+use dipstick::{AtomicBucket, InputQueueScope, InputScope, Stream, Input};
 
 fn main() {
     let bucket = AtomicBucket::new();
+    // NOTE: Wrapping an AtomicBucket with a Queue probably useless, as it is very fast and performs no I/O.
     let queue = InputQueueScope::wrap(bucket.clone(), 10000);
     let event = queue.marker("a");
     let args = &mut args();

examples/bucket2graphite.rs

@@ -1,8 +1,6 @@
 //! A sample application continuously aggregating metrics,
 //! printing the summary stats every three seconds
 
-extern crate dipstick;
-
 use dipstick::*;
 use std::time::Duration;
 

examples/bucket2stdout.rs

@@ -1,8 +1,6 @@
 //! A sample application continuously aggregating metrics,
 //! printing the summary stats every three seconds
 
-extern crate dipstick;
-
 use dipstick::*;
 use std::time::Duration;
 

examples/bucket_cleanup.rs

@@ -1,7 +1,5 @@
 //! Transient metrics are not retained by buckets after flushing.
 
-extern crate dipstick;
-
 use dipstick::*;
 
 use std::thread::sleep;

examples/bucket_summary.rs

@@ -1,8 +1,6 @@
 //! A sample application continuously aggregating metrics,
 //! printing the summary stats every three seconds
 
-extern crate dipstick;
-
 use dipstick::*;
 use std::time::Duration;
 

examples/buffered_flush_on_drop.rs

@@ -1,7 +1,5 @@
 //! Metrics are printed at the end of every cycle as scope is dropped
 
-extern crate dipstick;
-
 use std::thread::sleep;
 use std::time::Duration;
 

examples/cache.rs

@@ -1,7 +1,5 @@
 //! A sample application asynchronously printing metrics to stdout.
 
-extern crate dipstick;
-
 use dipstick::*;
 use std::io;
 use std::thread::sleep;

examples/clopwizard.rs

@@ -1,8 +1,6 @@
 //! A dropwizard-like configuration using three buckets
 //! aggregating one, five and fifteen minutes of data.
 
-extern crate dipstick;
-
 use dipstick::*;
 use std::thread::sleep;
 use std::time::Duration;

examples/custom_publish.rs

@@ -1,8 +1,6 @@
 //! A demonstration of customization of exported aggregated metrics.
 //! Using match on origin metric kind or score type to alter publication output.
 
-extern crate dipstick;
-
 use dipstick::*;
 use std::time::Duration;
 

examples/graphite.rs

@@ -1,7 +1,5 @@
 //! A sample application sending ad-hoc metrics to graphite.
 
-extern crate dipstick;
-
 use dipstick::*;
 use std::time::Duration;
 

examples/macro_proxy.rs

@@ -1,7 +1,5 @@
 //! A sample application sending ad-hoc counter values both to statsd _and_ to stdout.
 
-extern crate dipstick;
-
 use dipstick::*;
 
 use std::time::Duration;

examples/multi_input.rs

@@ -1,7 +1,5 @@
 //! A sample application sending ad-hoc counter values both to statsd _and_ to stdout.
 
-extern crate dipstick;
-
 use dipstick::{Graphite, Input, InputScope, MultiInput, Prefixed, Stream};
 use std::time::Duration;
 

examples/observer.rs

@@ -13,8 +13,6 @@
 //! ```
 //!
 
-extern crate dipstick;
-
 use std::time::{Duration, Instant};
 
 use dipstick::*;

examples/per_metric_sampling.rs

@@ -1,7 +1,5 @@
 //! A sample application sending ad-hoc marker values both to statsd _and_ to stdout.
 
-extern crate dipstick;
-
 use dipstick::*;
 use std::time::Duration;
 

examples/prometheus_labels.rs

@@ -1,7 +1,5 @@
 //! A sample application sending ad-hoc metrics to prometheus.
 
-extern crate dipstick;
-
 use dipstick::*;
 use std::time::Duration;
 

examples/proxy.rs

@@ -1,7 +1,5 @@
 //! Use the proxy to dynamically switch the metrics input & names.
 
-extern crate dipstick;
-
 use dipstick::{Input, InputScope, Prefixed, Proxy, Stream};
 use std::thread::sleep;
 use std::time::Duration;

examples/proxy_multi.rs

@@ -1,7 +1,5 @@
 //! Use the proxy to send metrics to multiple outputs
 
-extern crate dipstick;
-
 /// Create a pipeline that fans out
 /// The key here is to use AtomicBucket to read
 /// from the proxy and aggregate and flush metrics

examples/raw_log.rs

@@ -1,10 +1,7 @@
 //! Use the metrics backend directly to log a metric value.
 //! Applications should use the metrics()-provided instruments instead.
 
-#[macro_use]
-extern crate dipstick;
-
-use dipstick::{Input, InputScope, Labels};
+use dipstick::{Input, InputScope, Labels, labels};
 
 fn main() {
     raw_write()

examples/statsd_nosampling.rs

@@ -1,7 +1,5 @@
 //! A sample application sending ad-hoc counter values both to statsd _and_ to stdout.
 
-extern crate dipstick;
-
 use dipstick::*;
 use std::time::Duration;
 

examples/statsd_sampling.rs

@@ -1,7 +1,5 @@
 //! A sample application sending ad-hoc counter values both to statsd _and_ to stdout.
 
-extern crate dipstick;
-
 use dipstick::*;
 use std::time::Duration;
 

examples/text_format_label.rs

@@ -1,7 +1,5 @@
 //! Print metrics to stderr with custom formatter including a label.
 
-extern crate dipstick;
-
 use dipstick::{
     AppLabel, Formatting, Input, InputKind, InputScope, LabelOp, LineFormat, LineOp, LineTemplate,
     MetricName, Stream,

src/atomic.rs

@@ -2,7 +2,6 @@
 
 use crate::attributes::{Attributes, MetricId, OnFlush, Prefixed, WithAttributes};
 use crate::clock::TimeHandle;
-use crate::error;
 use crate::input::{Input, InputDyn, InputKind, InputMetric, InputScope};
 use crate::name::MetricName;
 use crate::stats::ScoreType::*;
@@ -11,7 +10,7 @@ use crate::{Flush, MetricValue, Void};
 
 use std::borrow::Borrow;
 use std::collections::BTreeMap;
-use std::fmt;
+use std::{fmt, io};
 use std::isize;
 use std::mem;
 use std::sync::atomic::AtomicIsize;
@@ -72,7 +71,7 @@ lazy_static! {
 }
 
 impl InnerAtomicBucket {
-    fn flush(&mut self) -> error::Result<()> {
+    fn flush(&mut self) -> io::Result<()> {
         let pub_scope: Arc<dyn InputScope> = match self.drain {
             Some(ref out) => out.input_dyn(),
             None => read_lock!(DEFAULT_AGGREGATE_INPUT).input_dyn(),
@@ -99,7 +98,7 @@ impl InnerAtomicBucket {
     /// Take a snapshot of aggregated values and reset them.
     /// Compute stats on captured values using assigned or default stats function.
     /// Write stats to assigned or default output.
-    fn flush_to(&mut self, target: &dyn InputScope) -> error::Result<()> {
+    fn flush_to(&mut self, target: &dyn InputScope) -> io::Result<()> {
         let now = TimeHandle::now();
         let duration_seconds = self.period_start.elapsed_us() as f64 / 1_000_000.0;
         self.period_start = now;
@@ -244,7 +243,7 @@ impl AtomicBucket {
     }
 
     /// Immediately flush the stats's metrics to the specified scope and stats.
-    pub fn flush_to(&self, publish_scope: &dyn InputScope) -> error::Result<()> {
+    pub fn flush_to(&self, publish_scope: &dyn InputScope) -> io::Result<()> {
         let mut inner = write_lock!(self.inner);
         inner.flush_to(publish_scope)
     }
@@ -267,7 +266,7 @@ impl InputScope for AtomicBucket {
 impl Flush for AtomicBucket {
     /// Collect and reset aggregated data.
     /// Publish statistics
-    fn flush(&self) -> error::Result<()> {
+    fn flush(&self) -> io::Result<()> {
         self.notify_flush_listeners();
         let mut inner = write_lock!(self.inner);
         inner.flush()

src/cache.rs

@@ -1,7 +1,6 @@
 //! Metric input scope caching.
 
 use crate::attributes::{Attributes, OnFlush, Prefixed, WithAttributes};
-use crate::error;
 use crate::input::{Input, InputDyn, InputKind, InputMetric, InputScope};
 use crate::lru_cache as lru;
 use crate::name::MetricName;
@@ -14,6 +13,7 @@ use std::sync::RwLock;
 
 #[cfg(feature = "parking_lot")]
 use parking_lot::RwLock;
+use std::io;
 
 /// Wrap an input with a metric definition cache.
 /// This can provide performance benefits for metrics that are dynamically defined at runtime on each access.
@@ -101,7 +101,7 @@ impl InputScope for InputScopeCache {
 }
 
 impl Flush for InputScopeCache {
-    fn flush(&self) -> error::Result<()> {
+    fn flush(&self) -> io::Result<()> {
         self.notify_flush_listeners();
         self.target.flush()
     }

src/error.rs

@@ -1,5 +0,0 @@
-use std::error;
-use std::result;
-
-/// Just put any error in a box.
-pub type Result<T> = result::Result<T, Box<dyn error::Error + Send + Sync>>;

src/lib.rs

@@ -53,7 +53,6 @@ macro_rules! read_lock {
 
 mod attributes;
 mod clock;
-mod error;
 mod input;
 mod label;
 mod metrics;
@@ -61,7 +60,6 @@ mod name;
 mod pcg32;
 mod proxy;
 mod scheduler;
-mod void;
 
 mod atomic;
 mod stats;
@@ -76,14 +74,13 @@ pub use crate::attributes::{
     Buffered, Buffering, Observe, ObserveWhen, OnFlush, OnFlushCancel, Prefixed, Sampled, Sampling,
 };
 pub use crate::clock::TimeHandle;
-pub use crate::error::Result;
 pub use crate::input::{
     Counter, Gauge, Input, InputDyn, InputKind, InputMetric, InputScope, Level, Marker, Timer,
 };
 pub use crate::label::{AppLabel, Labels, ThreadLabel};
 pub use crate::name::{MetricName, NameParts};
 pub use crate::scheduler::{Cancel, CancelGuard, CancelHandle, ScheduleFlush};
-pub use crate::void::Void;
+pub use crate::output::void::Void;
 
 #[cfg(test)]
 pub use crate::clock::{mock_clock_advance, mock_clock_reset};
@@ -109,13 +106,15 @@ pub use crate::multi::{MultiInput, MultiInputScope};
 pub use crate::queue::{InputQueue, InputQueueScope, QueuedInput};
 pub use crate::stats::{stats_all, stats_average, stats_summary, ScoreType};
 
+use std::io;
+
 /// Base type for recorded metric values.
 pub type MetricValue = isize;
 
 /// Both InputScope and OutputScope share the ability to flush the recorded data.
 pub trait Flush {
     /// Flush does nothing by default.
-    fn flush(&self) -> Result<()>;
+    fn flush(&self) -> io::Result<()>;
 }
 
 #[cfg(feature = "bench")]

src/macros.rs

@@ -23,8 +23,7 @@ macro_rules! time {
 /// ## Example
 ///
 /// ```
-/// #[macro_use] extern crate dipstick;
-///
+/// #[macro_use] ///
 /// use dipstick::*;
 ///
 /// # fn main() {

src/multi.rs

@@ -1,12 +1,12 @@
 //! Dispatch metrics to multiple sinks.
 
 use crate::attributes::{Attributes, MetricId, OnFlush, Prefixed, WithAttributes};
-use crate::error;
 use crate::input::{Input, InputDyn, InputKind, InputMetric, InputScope};
 use crate::name::MetricName;
 use crate::Flush;
 
 use std::sync::Arc;
+use std::io;
 
 /// Opens multiple scopes at a time from just as many outputs.
 #[derive(Clone, Default)]
@@ -102,7 +102,7 @@ impl InputScope for MultiInputScope {
 }
 
 impl Flush for MultiInputScope {
-    fn flush(&self) -> error::Result<()> {
+    fn flush(&self) -> io::Result<()> {
         self.notify_flush_listeners();
         for w in &self.scopes {
             w.flush()?;

src/output/format.rs

@@ -3,8 +3,9 @@ use crate::input::InputKind;
 use crate::name::MetricName;
 use crate::MetricValue;
 
-use std::io::{Error, Write};
+use std::io::{Write};
 use std::sync::Arc;
+use std::io;
 
 /// Print commands are steps in the execution of output templates.
 pub enum LineOp {
@@ -53,7 +54,7 @@ impl LineTemplate {
         output: &mut dyn Write,
         value: MetricValue,
         lookup: L,
-    ) -> Result<(), Error>
+    ) -> io::Result<()>
     where
         L: Fn(&str) -> Option<Arc<String>>,
     {

src/output/graphite.rs

@@ -6,7 +6,7 @@ use crate::input::{Input, InputMetric, InputScope};
 use crate::metrics;
 use crate::name::MetricName;
 use crate::output::socket::RetrySocket;
-use crate::{error, CachedInput, QueuedInput};
+use crate::{CachedInput, QueuedInput};
 use crate::{Flush, MetricValue};
 
 use std::net::ToSocketAddrs;
@@ -22,6 +22,7 @@ use std::sync::{RwLock, RwLockWriteGuard};
 
 #[cfg(feature = "parking_lot")]
 use parking_lot::{RwLock, RwLockWriteGuard};
+use std::io;
 
 /// Graphite Input holds a socket to a graphite server.
 /// The socket is shared between scopes opened from the Input.
@@ -45,7 +46,7 @@ impl Input for Graphite {
 
 impl Graphite {
     /// Send metrics to a graphite server at the address and port provided.
-    pub fn send_to<A: ToSocketAddrs + Debug + Clone>(address: A) -> error::Result<Graphite> {
+    pub fn send_to<A: ToSocketAddrs + Debug + Clone>(address: A) -> io::Result<Graphite> {
         debug!("Connecting to graphite {:?}", address);
         let socket = Arc::new(RwLock::new(RetrySocket::new(address)?));
 
@@ -98,7 +99,7 @@ impl InputScope for GraphiteScope {
 }
 
 impl Flush for GraphiteScope {
-    fn flush(&self) -> error::Result<()> {
+    fn flush(&self) -> io::Result<()> {
         self.notify_flush_listeners();
         let buf = write_lock!(self.buffer);
         self.flush_inner(buf)
@@ -140,7 +141,7 @@ impl GraphiteScope {
         }
     }
 
-    fn flush_inner(&self, mut buf: RwLockWriteGuard<String>) -> error::Result<()> {
+    fn flush_inner(&self, mut buf: RwLockWriteGuard<String>) -> io::Result<()> {
         if buf.is_empty() {
             return Ok(());
         }

src/output/log.rs

@@ -3,7 +3,7 @@ use crate::input::{Input, InputKind, InputMetric, InputScope};
 use crate::name::MetricName;
 use crate::output::format::{Formatting, LineFormat, SimpleFormat};
 use crate::Flush;
-use crate::{error, CachedInput, QueuedInput};
+use crate::{CachedInput, QueuedInput};
 
 use std::sync::Arc;
 
@@ -14,6 +14,7 @@ use std::sync::RwLock;
 use parking_lot::RwLock;
 
 use std::io::Write;
+use std::io;
 
 /// Buffered metrics log output.
 #[derive(Clone)]
@@ -146,7 +147,7 @@ impl InputScope for LogScope {
 }
 
 impl Flush for LogScope {
-    fn flush(&self) -> error::Result<()> {
+    fn flush(&self) -> io::Result<()> {
         self.notify_flush_listeners();
         let mut entries = write_lock!(self.entries);
         if !entries.is_empty() {

src/output/map.rs

@@ -4,9 +4,9 @@ use crate::name::MetricName;
 use crate::{Flush, MetricValue};
 
 use std::collections::BTreeMap;
-use std::error::Error;
 
 use std::sync::{Arc, RwLock};
+use std::io;
 
 /// A BTreeMap wrapper to receive metrics or stats values.
 /// Every received value for a metric replaces the previous one (if any).
@@ -64,7 +64,7 @@ impl InputScope for StatsMapScope {
 }
 
 impl Flush for StatsMapScope {
-    fn flush(&self) -> Result<(), Box<dyn Error + Send + Sync>> {
+    fn flush(&self) -> io::Result<()> {
         self.notify_flush_listeners();
         Ok(())
     }

src/output/mod.rs

@@ -1,3 +1,5 @@
+pub mod void;
+
 pub mod format;
 
 pub mod map;

src/output/prometheus.rs

@@ -1,7 +1,6 @@
 //! Send metrics to a Prometheus server.
 
 use crate::attributes::{Attributes, Buffered, MetricId, OnFlush, Prefixed, WithAttributes};
-use crate::error;
 use crate::input::InputKind;
 use crate::input::{Input, InputMetric, InputScope};
 use crate::label::Labels;
@@ -17,6 +16,7 @@ use std::sync::{RwLock, RwLockWriteGuard};
 
 #[cfg(feature = "parking_lot")]
 use parking_lot::{RwLock, RwLockWriteGuard};
+use std::io;
 
 /// Prometheus Input holds a socket to a Prometheus server.
 /// The socket is shared between scopes opened from the Input.
@@ -43,7 +43,7 @@ impl Prometheus {
     /// URL path must include group identifier labels `job`
     /// as shown in https://github.com/prometheus/pushgateway#command-line
     /// For example `http://pushgateway.example.org:9091/metrics/job/some_job`
-    pub fn push_to(url: &str) -> error::Result<Prometheus> {
+    pub fn push_to(url: &str) -> io::Result<Prometheus> {
         debug!("Pushing to Prometheus {:?}", url);
 
         Ok(Prometheus {
@@ -95,7 +95,7 @@ impl InputScope for PrometheusScope {
 }
 
 impl Flush for PrometheusScope {
-    fn flush(&self) -> error::Result<()> {
+    fn flush(&self) -> io::Result<()> {
         self.notify_flush_listeners();
         let buf = write_lock!(self.buffer);
         self.flush_inner(buf)
@@ -154,7 +154,7 @@ impl PrometheusScope {
         }
     }
 
-    fn flush_inner(&self, mut buf: RwLockWriteGuard<String>) -> error::Result<()> {
+    fn flush_inner(&self, mut buf: RwLockWriteGuard<String>) -> io::Result<()> {
         if buf.is_empty() {
             return Ok(());
         }
@@ -176,7 +176,7 @@ impl PrometheusScope {
             Err(e) => {
                 metrics::PROMETHEUS_SEND_ERR.mark();
                 debug!("Failed to send buffer to Prometheus: {}", e);
-                Err(e.into())
+                Err(io::Error::new(io::ErrorKind::Other, e))
             }
         }
     }

src/output/statsd.rs

@@ -7,8 +7,8 @@ use crate::input::InputKind;
 use crate::input::{Input, InputMetric, InputScope};
 use crate::name::MetricName;
 use crate::pcg32;
-use crate::{error, CachedInput, LineFormat, LineTemplate, QueuedInput};
-use crate::{metrics, LineOp};
+use crate::{CachedInput, QueuedInput};
+use crate::{metrics};
 use crate::{Flush, MetricValue};
 
 use std::net::ToSocketAddrs;
@@ -20,6 +20,7 @@ use std::sync::{RwLock, RwLockWriteGuard};
 
 #[cfg(feature = "parking_lot")]
 use parking_lot::{RwLock, RwLockWriteGuard};
+use std::io;
 
 /// Use a safe maximum size for UDP to prevent fragmentation.
 // TODO make configurable?
@@ -35,7 +36,7 @@ pub struct Statsd {
 
 impl Statsd {
     /// Send metrics to a statsd server at the address and port provided.
-    pub fn send_to<ADDR: ToSocketAddrs>(address: ADDR) -> error::Result<Statsd> {
+    pub fn send_to<ADDR: ToSocketAddrs>(address: ADDR) -> io::Result<Statsd> {
         let socket = Arc::new(UdpSocket::bind("0.0.0.0:0")?);
         socket.set_nonblocking(true)?;
         socket.connect(address)?;
@@ -136,7 +137,7 @@ impl InputScope for StatsdScope {
 }
 
 impl Flush for StatsdScope {
-    fn flush(&self) -> error::Result<()> {
+    fn flush(&self) -> io::Result<()> {
         self.notify_flush_listeners();
         let buf = write_lock!(self.buffer);
         self.flush_inner(buf)
@@ -177,7 +178,7 @@ impl StatsdScope {
         }
     }
 
-    fn flush_inner(&self, mut buffer: RwLockWriteGuard<String>) -> error::Result<()> {
+    fn flush_inner(&self, mut buffer: RwLockWriteGuard<String>) -> io::Result<()> {
         if !buffer.is_empty() {
             match self.socket.send(buffer.as_bytes()) {
                 Ok(size) => {
@@ -223,41 +224,41 @@ impl Drop for StatsdScope {
     }
 }
 
-use crate::output::format::LineOp::{ScaledValueAsText, ValueAsText};
-
-impl LineFormat for StatsdScope {
-    fn template(&self, name: &MetricName, kind: InputKind) -> LineTemplate {
-        let mut prefix = name.join(".");
-        prefix.push(':');
-
-        let mut suffix = String::with_capacity(16);
-        suffix.push('|');
-        suffix.push_str(match kind {
-            InputKind::Marker | InputKind::Counter => "c",
-            InputKind::Gauge | InputKind::Level => "g",
-            InputKind::Timer => "ms",
-        });
-
-        // specify sampling rate if any
-        if let Sampling::Random(float_rate) = self.get_sampling() {
-            suffix.push_str(&format! {"|@{}\n", float_rate});
-        }
-
-        // scale timer values
-        let op_value_text = match kind {
-            // timers are in µs, statsd wants ms
-            InputKind::Timer => ScaledValueAsText(1000.0),
-            _ => ValueAsText,
-        };
-
-        LineTemplate::new(vec![
-            LineOp::Literal(prefix.into_bytes()),
-            op_value_text,
-            LineOp::Literal(suffix.into_bytes()),
-            LineOp::NewLine,
-        ])
-    }
-}
+// use crate::output::format::LineOp::{ScaledValueAsText, ValueAsText};
+//
+// impl LineFormat for StatsdScope {
+//     fn template(&self, name: &MetricName, kind: InputKind) -> LineTemplate {
+//         let mut prefix = name.join(".");
+//         prefix.push(':');
+//
+//         let mut suffix = String::with_capacity(16);
+//         suffix.push('|');
+//         suffix.push_str(match kind {
+//             InputKind::Marker | InputKind::Counter => "c",
+//             InputKind::Gauge | InputKind::Level => "g",
+//             InputKind::Timer => "ms",
+//         });
+//
+//         // specify sampling rate if any
+//         if let Sampling::Random(float_rate) = self.get_sampling() {
+//             suffix.push_str(&format! {"|@{}\n", float_rate});
+//         }
+//
+//         // scale timer values
+//         let op_value_text = match kind {
+//             // timers are in µs, statsd wants ms
+//             InputKind::Timer => ScaledValueAsText(1000.0),
+//             _ => ValueAsText,
+//         };
+//
+//         LineTemplate::new(vec![
+//             LineOp::Literal(prefix.into_bytes()),
+//             op_value_text,
+//             LineOp::Literal(suffix.into_bytes()),
+//             LineOp::NewLine,
+//         ])
+//     }
+// }
 
 #[cfg(feature = "bench")]
 mod bench {

src/output/stream.rs

@@ -6,7 +6,7 @@ use crate::attributes::{Attributes, Buffered, MetricId, OnFlush, Prefixed, WithA
 use crate::input::InputKind;
 use crate::name::MetricName;
 use crate::Flush;
-use crate::{error, CachedInput, QueuedInput};
+use crate::{CachedInput, QueuedInput};
 
 use std::fs::{File, OpenOptions};
 use std::io::{self, Write};
@@ -55,12 +55,12 @@ impl Stream<File> {
     /// Write metric values to a file.
     #[deprecated(since = "0.8.0", note = "Use write_to_file()")]
     #[allow(clippy::wrong_self_convention)]
-    pub fn to_file<P: AsRef<Path>>(file: P) -> error::Result<Stream<File>> {
+    pub fn to_file<P: AsRef<Path>>(file: P) -> io::Result<Stream<File>> {
         Self::write_to_file(file)
     }
 
     /// Write metric values to a file.
-    pub fn write_to_file<P: AsRef<Path>>(file: P) -> error::Result<Stream<File>> {
+    pub fn write_to_file<P: AsRef<Path>>(file: P) -> io::Result<Stream<File>> {
         let file = OpenOptions::new()
             .write(true)
             .create(true)
@@ -75,7 +75,7 @@ impl Stream<File> {
     /// existing file, if false, the attempt will result in an error.
     #[deprecated(since = "0.8.0", note = "Use write_to_new_file()")]
     #[allow(clippy::wrong_self_convention)]
-    pub fn to_new_file<P: AsRef<Path>>(file: P, clobber: bool) -> error::Result<Stream<File>> {
+    pub fn to_new_file<P: AsRef<Path>>(file: P, clobber: bool) -> io::Result<Stream<File>> {
         Self::write_to_new_file(file, clobber)
     }
 
@@ -86,7 +86,7 @@ impl Stream<File> {
     pub fn write_to_new_file<P: AsRef<Path>>(
         file: P,
         clobber: bool,
-    ) -> error::Result<Stream<File>> {
+    ) -> io::Result<Stream<File>> {
         let file = OpenOptions::new()
             .write(true)
             .create(true)
@@ -223,7 +223,7 @@ impl<W: Write + Send + Sync + 'static> InputScope for TextScope<W> {
 }
 
 impl<W: Write + Send + Sync + 'static> Flush for TextScope<W> {
-    fn flush(&self) -> error::Result<()> {
+    fn flush(&self) -> io::Result<()> {
         self.notify_flush_listeners();
         let mut entries = write_lock!(self.entries);
         if !entries.is_empty() {

src/output/void.rs

@@ -3,8 +3,8 @@ use crate::Flush;
 
 use crate::attributes::MetricId;
 use crate::{Input, InputDyn, InputKind, InputMetric, InputScope};
-use std::error::Error;
 use std::sync::Arc;
+use std::io;
 
 lazy_static! {
     /// The reference instance identifying an uninitialized metric config.
@@ -50,7 +50,7 @@ impl InputScope for VoidInput {
 }
 
 impl Flush for VoidInput {
-    fn flush(&self) -> Result<(), Box<dyn Error + Send + Sync>> {
+    fn flush(&self) -> io::Result<()> {
         Ok(())
     }
 }

src/proxy.rs

@@ -1,14 +1,13 @@
 //! Decouple metric definition from configuration with trait objects.
 
 use crate::attributes::{Attributes, MetricId, OnFlush, Prefixed, WithAttributes};
-use crate::error;
 use crate::input::{InputKind, InputMetric, InputScope};
 use crate::name::{MetricName, NameParts};
-use crate::void::VOID_INPUT;
+use crate::output::void::VOID_INPUT;
 use crate::Flush;
 
 use std::collections::{BTreeMap, HashMap};
-use std::fmt;
+use std::{fmt, io};
 use std::sync::{Arc, Weak};
 
 #[cfg(not(feature = "parking_lot"))]
@@ -167,7 +166,7 @@ impl InnerProxy {
         }
     }
 
-    fn flush(&self, namespace: &NameParts) -> error::Result<()> {
+    fn flush(&self, namespace: &NameParts) -> io::Result<()> {
         if let Some((target, _nslen)) = self.get_effective_target(namespace) {
             target.flush()
         } else {
@@ -265,7 +264,7 @@ impl InputScope for Proxy {
 }
 
 impl Flush for Proxy {
-    fn flush(&self) -> error::Result<()> {
+    fn flush(&self) -> io::Result<()> {
         self.notify_flush_listeners();
         write_lock!(self.inner).flush(self.get_prefixes())
     }

src/queue.rs

@@ -3,7 +3,6 @@
 //! If queue size is exceeded, calling code reverts to blocking.
 
 use crate::attributes::{Attributes, MetricId, OnFlush, Prefixed, WithAttributes};
-use crate::error;
 use crate::input::{Input, InputDyn, InputKind, InputMetric, InputScope};
 use crate::label::Labels;
 use crate::metrics;
@@ -14,7 +13,7 @@ use crate::{Flush, MetricValue};
 #[cfg(not(feature = "crossbeam-channel"))]
 use std::sync::mpsc;
 use std::sync::Arc;
-use std::thread;
+use std::{thread, io};
 
 #[cfg(feature = "crossbeam-channel")]
 use crossbeam_channel as crossbeam;
@@ -199,12 +198,12 @@ impl InputScope for InputQueueScope {
 }
 
 impl Flush for InputQueueScope {
-    fn flush(&self) -> error::Result<()> {
+    fn flush(&self) -> io::Result<()> {
         self.notify_flush_listeners();
         if let Err(e) = self.sender.send(InputQueueCmd::Flush(self.target.clone())) {
             metrics::SEND_FAILED.mark();
             debug!("Failed to flush async metrics: {}", e);
-            Err(e.into())
+            Err(io::Error::new(io::ErrorKind::Other, e))
         } else {
             Ok(())
         }