1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
|
# Solve
[][gem] [][travis]
A Ruby versioning constraint solver implementing [Semantic Versioning 2.0.0](http://semver.org).
## Installation
```shell
$ gem install solve
```
## Usage
Create a new graph
```ruby
graph = Solve::Graph.new
```
Add an artifact to the graph
```ruby
graph.artifact("nginx", "1.0.0")
```
Now add another artifact that has a dependency
```ruby
graph.artifact("mysql", "1.2.4-alpha.1").depends("openssl", "~> 1.0.0")
```
Dependencies can be chained, too
```ruby
graph.artifact("ntp", "1.0.0").depends("build-essential").depends("yum")
```
And now solve the graph with some demands
```ruby
Solve.it!(graph, [['nginx', '>= 0.100.0']])
```
Or, if you want a topologically sorted solution NOTE: This will raise Solve::Errors::UnsortableSolutionError if the solution contains a cycle (which can happen with ruby packages)
```ruby
Solve.it!(graph, [['nginx', '>= 0.100.0']], sorted: true)
```
### Selecting A Resolver
Solve supports two different resolvers. A pure Ruby solver implemented using [Molinillo](https://github.com/CocoaPods/Molinillo) and the same dependency resolver the Chef Server uses, [dep-selector](https://github.com/chef/dep-selector), which is a Ruby C extension for [Gecode](https://github.com/ampl/gecode).
You can set the resolver by calling `Solve.engine=` with the symbol `:ruby` or `:gecode`.
```ruby
Solve.engine = :ruby
Solve.engine = :gecode
```
The Ruby solver is installed and enabled by default. If you'd like to use the Gecode solver you can do so by installing the dep-selector gem or adding it to your Gemfile:
```shell
$ gem install dep_selector
```
### Increasing the solver's timeout
By default the solver will wait 30 seconds before giving up on finding a solution. Under certain conditions a graph may be too complicated to solve within the alotted time. To increase the timeout you can set the "SOLVE_TIMEOUT" environment variable to the amount of seconds desired.
```shell
$ export SOLVE_TIMEOUT=60
```
This will set the timeout to 60 seconds instead of the default 30 seconds.
## Authors
- [Jamie Winsor](https://github.com/reset) ([jamie@vialstudios.com](mailto:jamie@vialstudios.com))
- [Andrew Garson](andrewGarson) ([agarson@riotgames.com](mailto:agarson@riotgames.com))
- [Thibaud Guillaume-Gentil](https://github.com/thibaudgg) ([@thibaudgg](http://twitter.com/thibaudgg))
[gem]: https://rubygems.org/gems/solve
[travis]: http://travis-ci.org/berkshelf/solve
|
