justbus-rs is a lightweight backend that serves LTA Datamall bus arrival timings with a strong emphasis on low memory usage, high throughput and low latency. This project uses lta-rs internally.
Bus Arrival Timings
GET http://localhost:8080/api/v1/timings/<bus_stop_no>
Click to show API response
[
{
"service_no": "15",
"operator": "GAS",
"next_bus": [
{
"origin_code": 77009,
"dest_code": 77009,
"est_arrival": "2020-01-04T15:12:31 08:00",
"lat": 1.3254953333333335,
"long": 103.90585966666667,
"visit_no": 1,
"load": "SeatsAvailable",
"feature": "WheelChairAccessible",
"bus_type": "SingleDecker"
},
{
"origin_code": 77009,
"dest_code": 77009,
"est_arrival": "2020-01-04T15:19:03 08:00",
"lat": 1.3351438333333334,
"long": 103.9091055,
"visit_no": 1,
"load": "SeatsAvailable",
"feature": "WheelChairAccessible",
"bus_type": "SingleDecker"
},
{
"origin_code": 77009,
"dest_code": 77009,
"est_arrival": "2020-01-04T15:33:05 08:00",
"lat": 1.3486306666666667,
"long": 103.9426515,
"visit_no": 1,
"load": "SeatsAvailable",
"feature": "WheelChairAccessible",
"bus_type": "SingleDecker"
}
]
},
{
"service_no": "150",
"operator": "SBST",
"next_bus": [
{
"origin_code": 82009,
"dest_code": 82009,
"est_arrival": "2020-01-04T15:07:50 08:00",
"lat": 1.3147168333333332,
"long": 103.90623166666667,
"visit_no": 1,
"load": "SeatsAvailable",
"feature": "WheelChairAccessible",
"bus_type": "SingleDecker"
},
{
"origin_code": 82009,
"dest_code": 82009,
"est_arrival": "2020-01-04T15:20:54 08:00",
"lat": 0.0,
"long": 0.0,
"visit_no": 1,
"load": "SeatsAvailable",
"feature": "WheelChairAccessible",
"bus_type": "SingleDecker"
},
{
"origin_code": 82009,
"dest_code": 82009,
"est_arrival": "2020-01-04T15:32:54 08:00",
"lat": 0.0,
"long": 0.0,
"visit_no": 1,
"load": "SeatsAvailable",
"feature": "WheelChairAccessible",
"bus_type": "SingleDecker"
}
]
},
{
"service_no": "155",
"operator": "SBST",
"next_bus": [
{
"origin_code": 52009,
"dest_code": 84009,
"est_arrival": "2020-01-04T15:07:39 08:00",
"lat": 1.31445,
"long": 103.90634883333334,
"visit_no": 1,
"load": "StandingAvailable",
"feature": "WheelChairAccessible",
"bus_type": "SingleDecker"
},
{
"origin_code": 52009,
"dest_code": 84009,
"est_arrival": "2020-01-04T15:24:52 08:00",
"lat": 1.3201654999999999,
"long": 103.88181566666667,
"visit_no": 1,
"load": "SeatsAvailable",
"feature": "WheelChairAccessible",
"bus_type": "SingleDecker"
},
{
"origin_code": 52009,
"dest_code": 84009,
"est_arrival": "2020-01-04T15:42:38 08:00",
"lat": 1.3347515,
"long": 103.8782805,
"visit_no": 1,
"load": "StandingAvailable",
"feature": "WheelChairAccessible",
"bus_type": "SingleDecker"
}
]
}
]The following features can be activated during compile time. Multiple caching strategies are implemented as different machines perform differently with each of them. A machine with lesser physical cores may benefit more from cht and dashmap whereas a higher core machine may not see any difference between any of the caching strategies. Like always, you should benchmark them yourself if performance is a concern!
swisstable(recommended/default)dashmapchttls(using Rustls)loggingnightly(To be paired withswisstable, enables hardware lock elision forRwLock)
- Caching response with a hashmap
- Amortised serialisation of data structures
jemalloc
Disclaimer: benchmarks are naive and YMMV
AMD Ryzen 3600 @ 4.3Ghz (stock) 16G ram @ 3600Mhz, ubuntu 20.04 LTS
wrk -c100 -d15s -t6 http://localhost:8080/api/v1/timings/83139
Running 15s test @ http://localhost:8080/api/v1/timings/83139
6 threads and 100 connections
Thread Stats Avg Stdev Max /- Stdev
Latency 1.40ms 4.49ms 109.89ms 92.99%
Req/Sec 126.60k 33.29k 172.64k 74.11%
11357888 requests in 15.05s, 23.48GB read
Non-2xx or 3xx responses: 59
Requests/sec: 754475.17
Transfer/sec: 1.56GB
Memory Usage @ Peak: 21MB
Requirements: jemalloc and libssl. Rust 1.51.0 is required at minimum.
Binary will be at /target/release folder.
# Vanilla build
cargo build
# Lets say we want to use dashmap, logging and tls
cargo build --release --features tls,logging,dashmap
# How about default and nightly
cargo build --release --features nightly
cd ./target/release
./justbus-rs --ip-addr IP_ADDR_YOU_WANT_WITH_PORT --api-key YOUR_API_KEY
# Do note that ip-addr is optional and will default to 127.0.0.1:8080 if nothing is provided
# api-key is a must
We put the self-signed certificate in this directory as an example but your browser would complain that it isn't secure. So we recommend to use mkcert to trust it. To use local CA, you should run:
mkcert -install
If you want to generate your own cert/private key file, then run:
mkcert localhost
openssl rsa -in localhost-key.pem -out key-rsa.pem
# Then run the program normally
By default, docker image uses swisstable feature. If you need the other features, you will need to modify Dockerfile and build your own image.
docker pull inverse/justbus_rs
docker run -d -p 8080:8080 inverse/justbus_rs --api-key YOUR_API_KEY --ip-addr 0.0.0.0:8080
Do send a PR if you think you have improvements to make whether to the actual codebase or any of the documentation!
justbus-rs is licensed under MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)