Skip to content

Commit

Permalink
Initial project structure and README file with the description of wha…
Browse files Browse the repository at this point in the history
…t we're going to do
  • Loading branch information
kachayev committed Jun 1, 2015
0 parents commit 2b5c0c7
Show file tree
Hide file tree
Showing 4 changed files with 161 additions and 0 deletions.
16 changes: 16 additions & 0 deletions .gitignore
Original file line number Diff line number Diff line change
@@ -0,0 +1,16 @@
/target
/lib
/classes
/checkouts
pom.xml
pom.xml.asc
*.jar
*.class
.lein-deps-sum
.lein-failures
.lein-plugins
.lein-repl-history
.lein-env
*.pyc
.nrepl-port
*~
20 changes: 20 additions & 0 deletions LICENSE
Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
Copyright (c) 2015 Alexey Kachayev

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
117 changes: 117 additions & 0 deletions README.md
Original file line number Diff line number Diff line change
@@ -0,0 +1,117 @@
## Muse

*Muse* is a Clojure library that works hard to make your relationship with remote data simple & enjoyable. We believe that concurrent code can be elegant and efficient at the same time.

Often times your business logic relies on remote data that you need to fetch from different sources: databases, caches, web services or 3rd party APIs, and you can't mess things up. *Muse* helps you to keep your business logic clear of low-level details while performing efficiently:

* batch multiple requests (if batching protocol is defined for the data source)
* request data from multiple data sources concurrently
* cache previous results to reduce # of fetch requests

Having all this gives you the ability to access remote data sources in a concise and consistent way, while the library handles batching and overlapping requests to multiple data sources behind the scenes.

Heavily inspired by:

* [Haxl](https://github.com/facebook/Haxl) - Haskell library, Facebook, open-sourced
* [Stitch](https://www.youtube.com/watch?v=VVpmMfT8aYw) - Scala library, Twitter, not open-sourced

## Usage

Add this dependency to your project file:

```clojure
[muse "0.3.1"]
```

Use it in your code:

```clojure
(ns my.ns
(:require [muse.core :as muse]
[clojure.core.async :refer [go <!!]]))

(defrecord Timeline [username]
muse/AResource
(fetch [_] (go (range 10))))

(<!! (muse/fmap count (Timeline. "@alexey")))
```

## Example

```clojure
(defrecord UserScore [id]
muse/AResource
(fetch [_] (go (rand 100))))
```

Compare 2 users activity:

```clojure
(defn compare-users
[id1 id2]
(muse/run! (muse/fmap compare (UserScore. id1) (UserScore. id2))))
```

Find the most active user:

```clojure
(defn most-active-user []
(muse/run! (->> (range 100)
(map (fn [id] (muse/fmap vector id (UserScore. id))))
(muse/fmap #(->> % (sort-by second) ffirst)))))
```

You can use monads library that you like, i.e. `core.algo` or `cats`:

```clojure
(defn fetch-post [id]
(mlet [post (Post. id)
user (User. (:author-id post))]
(return (assoc post :author user))))
```

If you came from Haskell you will probably like shortcuts:

```clojure
(defn compare-users
[id1 id2]
(<$> compare (UserScore. id1) (UserScore. id2)))
```

Find more sophisticated examples in `test` directory:

* fetching social timeline

* calculating friends-of-friends list

* and more

## How Does It Work?

* you define data sources that you want to work with using `AResource` protocol (describe how `fetch` should be executed)

* you declare what do you want to do with the result of each data source fetch (yeah, your resource is a functor now)

* `muse` build AST of all operations placing data source fetching points as leaves (yeah, this is [free monads](http://goo.gl/1ubHUa) approach)

* `muse` implicitely rebuild AST to work with tree levels instead of separated leave that gives ability to batch requests and run independent fetches concurrently

* you call `muse/run!` interpreter that reduce AST level by level until the whole computation is finished

## Future Ideas

- [ ] `flat-map` operation
- [ ] split AResource to few protocols
- [ ] use ReadPort protocol to avoid explicit `run!` call
- [ ] composibility with `core.algo` and `cats` libraries
- [ ] catch & propagate exceptions
- [ ] clean up code, test coverage, better high-level API

## License

Release under the MIT license. See LICENSE for the full license.

## Thanks

Thanks go to Simon Marlow for creating/leading Haxl project (and talking about it). And to Facebook for open-sourcing it.
8 changes: 8 additions & 0 deletions project.clj
Original file line number Diff line number Diff line change
@@ -0,0 +1,8 @@
(defproject muse "0.3.1"
:description "A Clojure library that simplifies access to remote data (db, cache, http services)"
:url "https://github.com/kachayev/muse"
:license {:name "The MIT License"
:url "http://opensource.org/licenses/MIT"
:distribution :repo}
:global-vars {*warn-on-reflection* true}
:dependencies [[org.clojure/core.async "0.1.346.0-17112a-alpha"]])

0 comments on commit 2b5c0c7

Please sign in to comment.