Ecosyste.ms: Packages

An open API service providing package, version and dependency metadata of many open source software ecosystems and registries.

crates.io "tracing" keyword

Top 8.5% on crates.io
fast_log 1.6.16
Rust async log High-performance asynchronous logging
148 versions - Latest release: 2 months ago - 9 dependent packages - 28 dependent repositories - 105 thousand downloads total - 205 stars on GitHub - 1 maintainer
Top 0.6% on crates.io
tracing-subscriber 0.3.18 💰
Utilities for implementing and composing `tracing` subscribers.
62 versions - Latest release: 6 months ago - 2,641 dependent packages - 20,007 dependent repositories - 92.7 million downloads total - 4,974 stars on GitHub - 2 maintainers
Top 4.7% on crates.io
tracing-actix-web 0.7.10
Structured logging middleware for actix-web.
54 versions - Latest release: 2 months ago - 34 dependent packages - 557 dependent repositories - 2.27 million downloads total - 221 stars on GitHub - 1 maintainer
Top 0.6% on crates.io
tracing 0.1.40 💰
Application-level tracing for Rust.
42 versions - Latest release: 7 months ago - 5,083 dependent packages - 43,966 dependent repositories - 153 million downloads total - 4,974 stars on GitHub - 1 maintainer
Top 0.6% on crates.io
tracing-core 0.1.32 💰
Core primitives for application-level tracing.
34 versions - Latest release: 7 months ago - 133 dependent packages - 42,227 dependent repositories - 153 million downloads total - 4,974 stars on GitHub - 1 maintainer
opentelemetry-application-insights 0.31.0
OpenTelemetry exporter for Azure Application Insights
34 versions - Latest release: about 15 hours ago - 1 dependent package - 92 dependent repositories - 1.19 million downloads total - 21 stars on GitHub - 1 maintainer
nvbit-sys 0.0.38
Native bindings to the NVIDIA NVBIT binary instrumentation library
31 versions - Latest release: 7 months ago - 1 dependent package - 1 dependent repositories - 53.2 thousand downloads total - 2 stars on GitHub - 1 maintainer
nvbit-build 0.0.38
Build-time helpers for compiling NVIDIA NVBIT instrumentation
31 versions - Latest release: 7 months ago - 1 dependent repositories - 52.5 thousand downloads total - 2 stars on GitHub - 1 maintainer
Top 7.0% on crates.io
axum-tracing-opentelemetry 0.18.0 💰
Middlewares and tools to integrate axum + tracing + opentelemetry
31 versions - Latest release: 2 months ago - 6 dependent packages - 114 dependent repositories - 594 thousand downloads total - 110 stars on GitHub - 1 maintainer
Top 1.5% on crates.io
opentelemetry 0.22.0
A metrics collection and distributed tracing framework
30 versions - Latest release: 3 months ago - 192 dependent packages - 2,155 dependent repositories - 29.6 million downloads total - 1,488 stars on GitHub - 1 maintainer
nvbit-rs 0.0.38
Idiomatic library for using the NVIDIA NVBIT binary instrumentation library
29 versions - Latest release: 7 months ago - 1 dependent repositories - 52.1 thousand downloads total - 2 stars on GitHub - 1 maintainer
Top 3.9% on crates.io
tracing-opentelemetry 0.23.0 💰
OpenTelemetry integration for tracing
28 versions - Latest release: 2 months ago - 121 dependent packages - 1,520 dependent repositories - 24.4 million downloads total - 156 stars on GitHub - 3 maintainers
Top 0.7% on crates.io
tracing-attributes 0.1.27 💰
Procedural macro attributes for automatically instrumenting functions.
28 versions - Latest release: 7 months ago - 43 dependent packages - 26,922 dependent repositories - 121 million downloads total - 4,974 stars on GitHub - 1 maintainer
test_logs 0.1.26 💰
Library to see logs in tests
27 versions - Latest release: 2 months ago - 2 dependent packages - 8.67 thousand downloads total - 654 stars on GitHub - 1 maintainer
tracing-timing 0.6.0
Inter-event timing metrics on top of tracing.
25 versions - Latest release: about 2 years ago - 2 dependent packages - 7 dependent repositories - 70.7 thousand downloads total - 103 stars on GitHub - 1 maintainer
Top 5.6% on crates.io
tracing-bunyan-formatter 0.3.9
A Bunyan formatter for the tracing crate
25 versions - Latest release: 9 months ago - 36 dependent packages - 970 dependent repositories - 2.83 million downloads total - 77 stars on GitHub - 1 maintainer
aquavm-air-cli 0.8.0
AIR execution and printing tool
23 versions - Latest release: 23 days ago - 4.87 thousand downloads total - 76 stars on GitHub - 1 maintainer
Top 9.6% on crates.io
zipkin 0.4.2
A library for collecting timing information about distributed computations
22 versions - Latest release: over 3 years ago - 5 dependent packages - 11 dependent repositories - 91.9 thousand downloads total - 53 stars on GitHub - 2 maintainers
Top 1.9% on crates.io
opentelemetry-jaeger 0.21.0
Jaeger exporter for OpenTelemetry
22 versions - Latest release: 3 months ago - 54 dependent packages - 636 dependent repositories - 7.8 million downloads total - 1,488 stars on GitHub - 1 maintainer
nvbit-io 0.0.38
NVIDIA NVBIT streaming encoder and decoder implementations using serde
21 versions - Latest release: 7 months ago - 1 dependent repositories - 84.9 thousand downloads total - 2 stars on GitHub - 1 maintainer
nvbit-model 0.0.38
NVIDIA NVBIT models for serialization and deserialization
21 versions - Latest release: 7 months ago - 1 dependent package - 1 dependent repositories - 92.4 thousand downloads total - 2 stars on GitHub - 1 maintainer
Top 4.0% on crates.io
opentelemetry-zipkin 0.20.0
Zipkin exporter for OpenTelemetry
21 versions - Latest release: 3 months ago - 8 dependent packages - 22 dependent repositories - 1.03 million downloads total - 1,488 stars on GitHub - 1 maintainer
pavex_tracing 0.1.38
The official integration between `tracing` and the Pavex framework.
20 versions - Latest release: 12 days ago - 5.19 thousand downloads total - 1,536 stars on GitHub - 1 maintainer
tracing-layer-slack 0.7.2
Send filtered tracing events to Slack
20 versions - Latest release: 19 days ago - 14.9 thousand downloads total - 8 stars on GitHub - 1 maintainer
Top 6.3% on crates.io
metrics-tracing-context 0.15.0
A crate to use tracing context as metrics labels.
20 versions - Latest release: 5 months ago - 1 dependent package - 157 dependent repositories - 874 thousand downloads total - 933 stars on GitHub - 1 maintainer
Top 5.3% on crates.io
reqwest-tracing 0.5.0
Opentracing middleware for reqwest.
20 versions - Latest release: 30 days ago - 37 dependent packages - 177 dependent repositories - 2.46 million downloads total - 220 stars on GitHub - 3 maintainers
tracing-chrometrace 0.1.19
A Layer for tracing-subscriber that outputs Chrome-style traces.
20 versions - Latest release: over 1 year ago - 1 dependent package - 128 thousand downloads total - 2 stars on GitHub - 1 maintainer
rtbvh 0.6.2
BVH library with various build algorithms and high performance using packet traversal.
19 versions - Latest release: almost 3 years ago - 4 dependent packages - 1 dependent repositories - 8.95 thousand downloads total - 17 stars on GitHub - 1 maintainer
tracing-gelf 0.8.0
A Graylog tracing library.
19 versions - Latest release: 4 months ago - 9 dependent repositories - 123 thousand downloads total - 14 stars on GitHub - 1 maintainer
holochain_tracing 0.0.24
abstraction for distributed tracing choices
18 versions - Latest release: about 4 years ago - 10 dependent packages - 3 dependent repositories - 30.5 thousand downloads total - 25 stars on GitHub - 1 maintainer
cs-trace 0.14.0
Tracing utilities.
17 versions - Latest release: over 1 year ago - 3 dependent packages - 1 dependent repositories - 11 thousand downloads total - 1 maintainer
Top 9.9% on crates.io
tracing-stackdriver 0.10.0
Stackdriver-compatible tracing layer and event formatter
17 versions - Latest release: about 2 months ago - 6 dependent packages - 13 dependent repositories - 406 thousand downloads total - 28 stars on GitHub - 1 maintainer
Top 9.8% on crates.io
autometrics-macros 1.0.1
Easily add metrics to your code that actually help you spot and debug issues in production. Buil...
17 versions - Latest release: 3 months ago - 1 dependent package - 14 dependent repositories - 159 thousand downloads total - 762 stars on GitHub - 3 maintainers
tracy_full 1.8.0
Fully featured bindings for the Tracy profiler
17 versions - Latest release: 5 days ago - 1 dependent repositories - 5.16 thousand downloads total - 16 stars on GitHub - 1 maintainer
Top 7.7% on crates.io
autometrics 1.0.1
Easily add metrics to your code that actually help you spot and debug issues in production. Buil...
17 versions - Latest release: 3 months ago - 4 dependent packages - 13 dependent repositories - 158 thousand downloads total - 769 stars on GitHub - 3 maintainers
holochain_tracing_macros 0.0.24
abstraction for distributed tracing choices
17 versions - Latest release: about 4 years ago - 9 dependent packages - 2 dependent repositories - 10.2 thousand downloads total - 25 stars on GitHub - 2 maintainers
renderdoc 0.12.1
RenderDoc application bindings for Rust
17 versions - Latest release: 2 months ago - 3 dependent packages - 19 dependent repositories - 64.6 thousand downloads total - 42 stars on GitHub - 1 maintainer
Top 2.6% on crates.io
opentelemetry-prometheus 0.15.0
Prometheus exporter for OpenTelemetry
16 versions - Latest release: 3 months ago - 29 dependent packages - 125 dependent repositories - 2.08 million downloads total - 1,488 stars on GitHub - 1 maintainer
embree4-rs 0.0.16
High-level wrapper for Intel's Embree 4 high-performance ray tracing library.
16 versions - Latest release: 8 months ago - 3.81 thousand downloads total - 3 stars on GitHub - 1 maintainer
tide-tracing 0.1.1
A simple middleware for tide using the tracing crate for logging.
15 versions - Latest release: 7 months ago - 2 dependent packages - 7 dependent repositories - 57.2 thousand downloads total - 37 stars on GitHub - 1 maintainer
opentelemetry-tide 0.12.0
OpenTelemetry integration for Tide
15 versions - Latest release: about 2 years ago - 1 dependent package - 2 dependent repositories - 8.45 thousand downloads total - 19 stars on GitHub - 1 maintainer
Top 2.1% on crates.io
opentelemetry-otlp 0.15.0
Exporter for the OpenTelemetry Collector
15 versions - Latest release: 3 months ago - 57 dependent packages - 923 dependent repositories - 11.8 million downloads total - 1,488 stars on GitHub - 1 maintainer
raster2svg 1.0.14
A tool that use the contour_tracing library.
15 versions - Latest release: about 2 years ago - 4.03 thousand downloads total - 8 stars on GitHub - 1 maintainer
modality-trace-recorder-plugin 0.9.0
A Modality reflector plugin suite and ingest adapter library for Percepio's TraceRecorder data
14 versions - Latest release: 2 months ago - 4.29 thousand downloads total - 0 stars on GitHub - 1 maintainer
Top 1.7% on crates.io
opentelemetry-semantic-conventions 0.14.0
Semantic conventions for OpenTelemetry
14 versions - Latest release: 3 months ago - 33 dependent packages - 1,014 dependent repositories - 16.9 million downloads total - 1,488 stars on GitHub - 1 maintainer
tracing-opentelemetry-instrumentation-sdk 0.18.0 💰
A set of helpers to build OpenTelemetry instrumentation based on `tracing` crate.
14 versions - Latest release: 2 months ago - 2 dependent packages - 1 dependent repositories - 151 thousand downloads total - 110 stars on GitHub - 1 maintainer
blazesym 0.2.0-alpha.12
blazesym is a library for address symbolization and related tasks.
14 versions - Latest release: 3 days ago - 2 dependent packages - 1 dependent repositories - 16 thousand downloads total - 65 stars on GitHub - 2 maintainers
Top 8.1% on crates.io
opentelemetry-contrib 0.14.0
Rust contrib repo for OpenTelemetry
14 versions - Latest release: 2 months ago - 1 dependent package - 4 dependent repositories - 88 thousand downloads total - 16 stars on GitHub - 1 maintainer
tracing-elastic-apm 3.3.0 💰
Elastic APM intake API tracing layer.
13 versions - Latest release: 3 days ago - 1 dependent repositories - 37.8 thousand downloads total - 22 stars on GitHub - 1 maintainer
trace4rs-config 0.5.1
trace4rs configuration
13 versions - Latest release: 9 months ago - 1 dependent package - 1 dependent repositories - 37.3 thousand downloads total - 5 stars on GitHub - 1 maintainer
tracing-fluentd 0.4.0 💰
Enables forwarding of `tracing` events towards the `fluentd` server.
13 versions - Latest release: about 1 year ago - 15.4 thousand downloads total - 7 stars on GitHub - 1 maintainer
contour_tracing 1.0.12
A 2D library to trace contours.
13 versions - Latest release: about 2 years ago - 1 dependent package - 4.54 thousand downloads total - 10 stars on GitHub - 1 maintainer
opentelemetry-datadog-cloudflare 0.11.0
Datadog exporters and propagators for OpenTelemetry for Cloudflare workers
13 versions - Latest release: about 1 year ago - 33.4 thousand downloads total - 8 stars on GitHub - 3 maintainers
traceon 0.3.1
An easy to use log and tracing formatter with a flattened json or pretty output.
13 versions - Latest release: 2 months ago - 7.33 thousand downloads total - 4 stars on GitHub - 1 maintainer
trace4rs-fmtorp 0.5.1
Torpid formatting for trace4rs
13 versions - Latest release: 9 months ago - 1 dependent package - 1 dependent repositories - 44 thousand downloads total - 5 stars on GitHub - 1 maintainer
diesel-tracing 0.2.5
Connection telemetry middleware for diesel and tracing
13 versions - Latest release: about 1 month ago - 1 dependent package - 6 dependent repositories - 14.8 thousand downloads total - 15 stars on GitHub - 1 maintainer
tracing-layer-discord 0.2.2
Send filtered tracing events to Discord
13 versions - Latest release: 19 days ago - 4.77 thousand downloads total - 0 stars on GitHub - 1 maintainer
tracing-gstreamer 0.7.0
Bridge between gstreamer and the tracing ecosystem
12 versions - Latest release: 3 months ago - 1 dependent repositories - 18.1 thousand downloads total - 32 stars on GitHub - 1 maintainer
trace4rs 0.5.1
log4rs like usability with the `tracing` crate as the base
12 versions - Latest release: 9 months ago - 1 dependent repositories - 36.2 thousand downloads total - 5 stars on GitHub - 1 maintainer
dyn-logger 0.2.7
Crate to configure tracing logger dynamically via configuration file in toml format.
12 versions - Latest release: 4 months ago - 3.08 thousand downloads total - 2 stars on GitHub - 1 maintainer
Top 2.7% on crates.io
opentelemetry-http 0.11.1
Helper implementations for sending HTTP requests. Uses include propagating and extracting context...
12 versions - Latest release: about 1 month ago - 27 dependent packages - 643 dependent repositories - 11.4 million downloads total - 1,488 stars on GitHub - 1 maintainer
Top 2.4% on crates.io
console-subscriber 0.2.0 💰
A `tracing-subscriber::Layer` for collecting Tokio console telemetry.
12 versions - Latest release: 7 months ago - 54 dependent packages - 1,871 dependent repositories - 5.34 million downloads total - 3,141 stars on GitHub - 1 maintainer
Top 6.7% on crates.io
test-env-log 0.2.8 💰
A replacement of the #[test] attribute that initializes logging and/or tracing infrastructure bef...
11 versions - Latest release: over 2 years ago - 68 dependent packages - 72 dependent repositories - 1.06 million downloads total - 94 stars on GitHub - 1 maintainer
Top 4.1% on crates.io
opentelemetry-datadog 0.10.0
Datadog exporters and propagators for OpenTelemetry
11 versions - Latest release: 2 months ago - 8 dependent packages - 24 dependent repositories - 4.24 million downloads total - 16 stars on GitHub - 1 maintainer
Top 5.7% on crates.io
minitrace 0.6.4
A high-performance timeline tracing library for Rust
11 versions - Latest release: 3 months ago - 7 dependent packages - 31 dependent repositories - 601 thousand downloads total - 677 stars on GitHub - 2 maintainers
log-tracing-layer 0.3.0 💰
Build your own custom tracing layer.
11 versions - Latest release: 5 months ago - 1 dependent package - 1 dependent repositories - 4.08 thousand downloads total - 4 stars on GitHub - 1 maintainer
dd-tracing-layer 0.3.0 💰
Send your logs to Datadog
11 versions - Latest release: 5 months ago - 3.75 thousand downloads total - 4 stars on GitHub - 1 maintainer
Top 7.9% on crates.io
minitrace-macro 0.6.4
Attribute procedural macro for minitrace-rust
11 versions - Latest release: 3 months ago - 1 dependent package - 28 dependent repositories - 605 thousand downloads total - 677 stars on GitHub - 2 maintainers
reqray 0.4.3
Log 'request x-rays' for rust programs instrumented with `tracing`.
11 versions - Latest release: about 2 years ago - 5.15 thousand downloads total - 41 stars on GitHub - 1 maintainer
tracing-indicatif 0.3.6
Tracing layer that automatically creates and manages progress bars for active spans.
11 versions - Latest release: 5 months ago - 5 dependent packages - 1 dependent repositories - 58.8 thousand downloads total - 161 stars on GitHub - 1 maintainer
tokio-console 0.1.10 💰
The Tokio console: a debugger for async Rust.
11 versions - Latest release: 7 months ago - 1 dependent repositories - 122 thousand downloads total - 3,141 stars on GitHub - 1 maintainer
Top 8.7% on crates.io
minitrace-jaeger 0.6.4
Jaeger reporter for minitrace-rust
11 versions - Latest release: 3 months ago - 2 dependent packages - 11 dependent repositories - 123 thousand downloads total - 677 stars on GitHub - 2 maintainers
init-tracing-opentelemetry 0.18.0 💰
A set of helpers to initialize (and more) tracing + opentelemetry (compose your own or use opinio...
11 versions - Latest release: 2 months ago - 1 dependent repositories - 49.5 thousand downloads total - 110 stars on GitHub - 1 maintainer
minitrace-datadog 0.6.4
Datadog reporter for minitrace-rust
11 versions - Latest release: 3 months ago - 1 dependent package - 6.55 thousand downloads total - 677 stars on GitHub - 2 maintainers
appinsights 0.2.3
Application Insights SDK for Rust
10 versions - Latest release: over 1 year ago - 1 dependent package - 4 dependent repositories - 49.9 thousand downloads total - 33 stars on GitHub - 1 maintainer
opentracingrust 0.4.0
opentracing.io library for rust
10 versions - Latest release: about 4 years ago - 5 dependent packages - 2 dependent repositories - 8.95 thousand downloads total - 7 stars on GitHub - 1 maintainer
opentracingrust_zipkin 0.3.1
Zipkin tracer for OpenTracingRust
10 versions - Latest release: about 4 years ago - 2 dependent packages - 2 dependent repositories - 7.2 thousand downloads total - 0 stars on GitHub - 1 maintainer
Top 5.2% on crates.io
opentelemetry-aws 0.10.0
AWS exporters and propagators for OpenTelemetry
10 versions - Latest release: 2 months ago - 6 dependent packages - 23 dependent repositories - 183 thousand downloads total - 16 stars on GitHub - 1 maintainer
embree4-sys 0.0.10
FFI bindings for Intel's Embree 4 high-performance ray tracing library.
10 versions - Latest release: 8 months ago - 1 dependent package - 2.75 thousand downloads total - 4 stars on GitHub - 1 maintainer
fake-opentelemetry-collector 0.18.0 💰
A Fake (basic) opentelemetry collector, useful to test what is collected opentelemetry
10 versions - Latest release: 2 months ago - 2.65 thousand downloads total - 110 stars on GitHub - 1 maintainer
Top 5.2% on crates.io
test-log 0.2.16 💰
A replacement of the #[test] attribute that initializes logging and/or tracing infrastructure bef...
10 versions - Latest release: 10 days ago - 324 dependent packages - 877 dependent repositories - 4.94 million downloads total - 94 stars on GitHub - 1 maintainer
tonic-tracing-opentelemetry 0.18.1 💰
Middlewares and tools to integrate tonic + tracing + opentelemetry.
10 versions - Latest release: 2 months ago - 15.2 thousand downloads total - 110 stars on GitHub - 1 maintainer
Top 6.5% on crates.io
tracing-chrome 0.7.2
A Layer for tracing-subscriber that outputs Chrome-style traces.
10 versions - Latest release: about 2 months ago - 30 dependent packages - 766 dependent repositories - 2.08 million downloads total - 80 stars on GitHub - 1 maintainer
Top 0.8% on crates.io
tracing-futures 0.2.5 💰
Utilities for instrumenting `futures` with `tracing`.
10 versions - Latest release: about 3 years ago - 357 dependent packages - 11,227 dependent repositories - 51 million downloads total - 4,974 stars on GitHub - 1 maintainer
tracing-worker 0.1.9
tracing-subscriber implementation for Cloudflare Workers worker crate
10 versions - Latest release: about 1 year ago - 1 dependent repositories - 2.53 thousand downloads total - 0 stars on GitHub - 1 maintainer
datadog-tracing 0.2.1
utilities for integrating Datadog with tracing
10 versions - Latest release: 3 months ago - 15.5 thousand downloads total - 13 stars on GitHub - 4 maintainers
ddtrace 0.1.1
utilities for integrating Datadog with tracing
9 versions - Latest release: 8 months ago - 6.46 thousand downloads total - 4 stars on GitHub - 1 maintainer
pyo3-opentelemetry 0.3.1
Macro and utilities for passing OpenTelemetry context from Python to Rust
9 versions - Latest release: 5 months ago - 2.63 thousand downloads total - 1 maintainer
Top 3.0% on crates.io
opentelemetry_sdk 0.22.1
The SDK for the OpenTelemetry metrics collection and distributed tracing framework
9 versions - Latest release: 2 months ago - 22 dependent packages - 1,280 dependent repositories - 14 million downloads total - 1,488 stars on GitHub - 2 maintainers
e-log 0.1.7
a rust log
9 versions - Latest release: 22 days ago - 1.48 thousand downloads total - 1 maintainer
cannonball_client 0.1.8
Cannonball client library for fast QEMU execution, memory, and syscall tracing.
9 versions - Latest release: over 1 year ago - 2.23 thousand downloads total - 73 stars on GitHub - 1 maintainer
pyo3-opentelemetry-macros 0.3.1
Macro for passing OpenTelemetry context from Python to Rust
9 versions - Latest release: 5 months ago - 1 dependent package - 2.78 thousand downloads total - 1 maintainer
tracing-logfmt 0.3.4
A logfmt formatter for tracing events and spans
9 versions - Latest release: 2 months ago - 2 dependent repositories - 204 thousand downloads total - 35 stars on GitHub - 1 maintainer
Top 0.7% on crates.io
tracing-log 0.2.0 💰
Provides compatibility between `tracing` and the `log` crate.
9 versions - Latest release: 7 months ago - 176 dependent packages - 17,073 dependent repositories - 82.4 million downloads total - 4,974 stars on GitHub - 1 maintainer
tracing-logstash 0.7.0
Minimal library to output logstash formatted events
9 versions - Latest release: 4 months ago - 9.71 thousand downloads total - 4 stars on GitHub - 1 maintainer
test-span 0.8.0
macro and utilities to do snapshot tests on tracing spans
9 versions - Latest release: 6 days ago - 3 dependent packages - 13 dependent repositories - 30.7 thousand downloads total - 11 stars on GitHub - 1 maintainer
truster 0.4.1
A ray tracing library based on the book 'The Ray Tracer Challenge' by Jamis Buck.
9 versions - Latest release: almost 3 years ago - 2.56 thousand downloads total - 0 stars on GitHub - 1 maintainer
axum-insights 0.3.2 💰
An Azure Application Insights exporter for axum via tracing.
8 versions - Latest release: 7 months ago - 2.14 thousand downloads total - 7 stars on GitHub - 1 maintainer
Top 4.0% on crates.io
console-api 0.6.0 💰
Protobuf wire format bindings for the Tokio console.
8 versions - Latest release: 7 months ago - 2 dependent packages - 1,126 dependent repositories - 5.37 million downloads total - 3,141 stars on GitHub - 1 maintainer
tracing-ecs 0.4.0
Tracing subscriber that output ECS (Elastic Common Schema) JSON log lines
8 versions - Latest release: 2 months ago - 2.27 thousand downloads total - 1 stars on GitHub - 1 maintainer