gohaystack

This is a toy library to play with Project Haystack in Go. It only relies on Go's standard library.

What is project-haystack?

As stated in the web site

"Project Haystack_ is an open-source initiative to streamline working with data from the Internet of Things. We standardize semantic data models and web services with the goal of making it easier to unlock value from the vast quantity of data being generated by the smart devices that permeate our homes, buildings, factories, and cities. Applications include automation, control, energy, HVAC, lighting, and other environmental systems."

-- Project-Haystack

What's included

This library is rather incomplete, as I am using it only for testing purpose (discovering haystack, building a sample server, and transform data from a format to another) This library has a Grid structure that can be (de)serialized to and from haystack format in JSON (no zinc yet). The Grid hold an array of Entity. An Entity has an id (format HaystackID which is a pointer to a string) a Dis field (a string used for display purpose) and a hash map of tags.

a tag is a composition of a *Label and a *Value

Please, see the API documentation for more information.

Haystack kind	JSON Serialize	JSON Deserialize	Zinc Serialize	Zinc Deserialize
Grid	x	x	x
List	x	x	x
Dict	x	x	x
Null	x	x	x
Bool	x	x	x
Marker	x	x	x
Remove	x	x	x
NA	x	x	x
Number	x	x	x
Ref	x	x	x
Str	x	x	x
Date	x	x	x
Time	x	x	x
DateTime	x	x	x
URI	x	x	x
Coord	x	x	x
Xstr

Haystack tags package

the tags subpackage contains the label and values definitions of the official haystack project tag list. This package is a commodity.

Example

Basic example

Generate a grid and add simple values:

g := NewGrid()
myTagLabel := NewLabel("mytag")
myTagSite := NewLabel("site")
myTagLabel.Display = "the display"
mySite := NewHaystackID("myreference")
entity := g.NewEntity(mySite)
myTagValue := NewStr("foo")
entity.SetTag(myTagLabel, myTagValue)
entity.SetTag(myTagSite, MarkerValue)

JSON

Generate a grid from a json payload:

g := grid.NewGrid()
dec := json.NewDecoder(os.Stdin)
err := dec.Decode(&g)
if err != nil {
    log.Fatal(err)
}

Complete example

the example/graph contains a CLI tool that reads a JSON encoded haystack grid from stdin and generates a dot compatible representation on stdout.

Caution

This is a toy project given without any warranty. I made it for my own need to discover haystack. If you want to take over the maintenance, feel free to contact me.