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https://github.com/twitter/pelikan

Pelikan is Twitter's unified cache backend
https://github.com/twitter/pelikan

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Pelikan is Twitter's unified cache backend

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README 

        
# Pelikan



Pelikan is Twitter's framework for developing cache services. It is:



* **Fast**: Pelikan provides high-throughput and low-latency caching solutions.



* **Reliable**: Pelikan is designed for large-scale deployment and the

  implementation is informed by our operational experiences.



* **Modular**: Pelikan is a framework for rapidly developing new caching

  solutions by focusing on the inherent architectural similarity between caching

  services and providing reusable low-level components.



[![License: Apache-2.0][license-badge]][license-url]

[![Build Status][cargo-build-badge]][cargo-build-url]

[![Fuzz Status][cargo-fuzz-badge]][cargo-fuzz-url]

[![Zulip Chat][zulip-badge]][zulip-url]



[Website](http://pelikan.io) |

[Chat][zulip-url]



# Content

* [Overview](#overview)

  * [Products](#products)

  * [Features](#features)

* [Build](#building-pelikan)

* [Usage](#usage)

* [Community](#community)

  * [Stay in touch](#stay-in-touch)

  * [Contributing](#contributing)

* [Documentation](#documentation)

* [License](#license)



# Overview

After years of using and working on various cache services, we built a common

framework that reveals the inherent architectural similarity among them.



By creating well-defined modules, most of the low-level functionalities are

reused as we create different binaries. The implementation learns from our

operational experiences to improve performance and reliability, and leads to

software designed for large-scale deployment.



The framework approach allows us to develop new features and protocols quickly.



## Products

Pelikan contains the following products:

- `pelikan_segcache_rs`: a Memcached-like server with extremely high memory

  efficiency and excellent core scalability. See our [NSDI'21 paper] for design

  and evaluation details.

- `pelikan_pingserver_rs`: an over-engineered, production-ready ping server

  useful as a tutorial and for measuring baseline RPC performance

- [`momento_proxy`][momento_proxy-url]: a proxy which allows existing 

  applications to use Momento instead of a Memcache-compatible cache backend.



## Legacy

Pelikan legacy codebase can be found within the `legacy` folder of this project.

It is composed of the original C codebase and backend implementations. It

remains as a reference, but is not recommended for production deployments.



## Features

- runtime separation of control and data plane

- predictably low latencies via lockless data structures, worker never blocks

- per-module config options and metrics that can be composed easily

- multiple storage and protocol implementations, easy to further extend

- low-overhead command logger for hotkey and other important data analysis



# Building Pelikan



## Requirement

- Rust [stable toolchain](https://www.rust-lang.org/learn/get-started)

- C toolchain: `llvm/clang (>= 7.0)`

- Build tools: `cmake (>= 3.2)`



## Build

```sh

git clone https://github.com/twitter/pelikan.git

cd pelikan

cargo build --release

```



## Tests

```sh

cargo test

```



# Usage

Using `pelikan_segcache_rs` as an example, other executables are highly similar.



To get info of the service, including usage format and options, run:

```sh

target/release/pelikan_segcache_rs --help

```



To launch the service with default settings, simply run:

```sh

target/release/pelikan_segcache_rs

```



To launch the service with the sample config file, run:

```sh

target/release/pelikan_segcache_rs config/segcache.toml

```



You should be able to try out the server using an existing memcached client,

or simply with `telnet`.

```sh

$ telnet localhost 12321

Trying 127.0.0.1...

Connected to localhost.

Escape character is '^]'.

set foo 0 0 3

bar

STORED

```



**Attention**: use `admin` port for all non-data commands.

```sh

$ telnet localhost 9999

Trying 127.0.0.1...

Connected to localhost.

Escape character is '^]'.

version

VERSION 0.1.0

stats

STAT pid 54937

STAT time 1459634909

STAT uptime 22

STAT version 100

STAT ru_stime 0.019172

...

```



## Configuration



Pelikan is file-first when it comes to configurations, and currently is

config-file only. You can create a new config file following the examples

included under the `config` directory.



# Community



## Stay in touch

- Join our project chat on [![Zulip][zulip-badge]][zulip-url]

  for questions and discussions

- Follow us on Twitter: [@pelikan_cache]

- Visit 



## Contributing



Please take a look at our [community manifesto](https://github.com/twitter/pelikan/blob/master/docs/manifesto.rst)

and [coding style guide](https://github.com/twitter/pelikan/blob/master/docs/coding_style.rst).



If you want to submit a patch, please follow these steps:



1. create a new issue

2. fork on github & clone your fork

3. create a feature branch on your fork

4. push your feature branch

5. create a pull request linked to the issue



# Documentation

We have made progress and are actively working on documentation, and will put it

on our website. Meanwhile, check out the current material under `docs/`



## License

This software is licensed under the Apache 2.0 license, see [LICENSE](LICENSE) for details.



[@pelikan_cache]: https://twitter.com/pelikan_cache

[cargo-build-badge]: https://img.shields.io/github/workflow/status/twitter/pelikan/cargo-build/master?label=build

[cargo-build-url]: https://github.com/twitter/pelikan/actions/workflows/cargo.yml?query=branch%3Amaster+event%3Apush

[cargo-fuzz-badge]: https://img.shields.io/github/workflow/status/twitter/pelikan/cargo-fuzz/master?label=fuzz

[cargo-fuzz-url]: https://github.com/twitter/pelikan/actions/workflows/fuzz.yml?query=branch%3Amaster+event%3Apush

[check]: (http://libcheck.github.io/check/)

[check-linker-bug]: (https://sourceforge.net/p/check/mailman/message/32835594/)

[license-badge]: https://img.shields.io/badge/license-Apache%202.0-blue.svg

[license-url]: https://github.com/twitter/pelikan/blob/master/LICENSE

[momento_proxy-url]: src/proxy/momento/README.md

[NSDI'21 paper]: https://www.usenix.org/conference/nsdi21/presentation/yang-juncheng

[zulip-badge]: https://img.shields.io/badge/zulip-join_chat-blue.svg

[zulip-url]: https://pelikan.zulipchat.com/