graph

graph

Graph is a library for handling graph functions.

Core concepts

Graph : representation of a transition of a group of components to its updated version. A graph is a combination of components and edges that will become on a graph changes.

• Component : represents an environment component like an instance, a sql server, anything can be a component as long as it exposes this interface
• Change : the processed component.
• Edge : transition from a source to a destination

Basic usage

In order to create a new graph you can use the default constructor:

g := graph.New(
  ID:       "id",
  Name:     "name",
  UserID:   "uID",
  Username: "john snow"
)

Lets add an instance as a new component:

instance := make(graph.GenericComponent)
instance["_action"] = "none"
instance["_component"] = "instances"
instance["_component_id"] = "instances::test1"
instance["_provider"] = "test"
instance["name"] = "john"
instance["size"] = "1024"

err = g.AddComponent(instance)

Actions

In order to get the edges for the creation of this component, you may want to change the _action field, this actually accepts different action. The previous example will look like:

instance := make(graph.GenericComponent)
instance["_action"] = "create"
instance["_component"] = "instances"
instance["_component_id"] = "instances::test1"
instance["_provider"] = "test"
instance["name"] = "john"
instance["size"] = "1024"

err = g.AddComponent(instance)

inspecting graph, will result on a set of valid edges to be processed.

Note: none action will result on non processing the specific component, so it wont be processed.

Diffs

Another interesting capability of graph library is the ability to calculate the diff between two graphs. This is accomplished with the Diff method and its variants.

You can find an example on how to diff graphs on the basic example

Managing dependencies

In many scenarios you may want to process a component before another, this causes a dependency between both. Graph library is also capable to manage that with Connect function family.

An easy to understand example is a sql server and its databases, you can't create databases before the server itself.

g := graph.New(
  ID:       "id",
  Name:     "name",
  UserID:   "uID",
  Username: "john snow"
)
server := make(graph.GenericComponent)
server["_component"] = "server"
server["_component_id"] = "server::test"
server["_provider"] = "test"
server["name"] = "mySQL"
err = g.AddComponent(server)

db := make(graph.GenericComponent)
db["_component"] = "db"
db["_component_id"] = "db::test"
db["_provider"] = "test"
db["name"] = "myDB"
err = g.AddComponent(db)

g.Connect(sql, db.GetID())

When you process this graph, you'll see that the sql server will be processed before the database.

Build status

• master:
• develop:

Installation

make deps
make install

or

go get github.com/r3labs/graph

Running Tests

make test

Contributing

Please read through our contributing guidelines. Included are directions for opening issues, coding standards, and notes on development.

Moreover, if your pull request contains patches or features, you must include relevant unit tests.

Versioning

For transparency into our release cycle and in striving to maintain backward compatibility, this project is maintained under the Semantic Versioning guidelines.

Copyright and License

Code and documentation copyright since 2015 r3labs.io authors.

Code released under the Mozilla Public License Version 2.0.