ducky/devices
2015-11-12
Child:c24a6c5fcd8c
ducky/devices/context.go
Initial attempt. Create the basic types (Device, DeviceType, DeviceChange) that we'll be using in the service. Also, create our Storer interface, and the helper methods to store, retrieve, and update information in the datastore. Also, we're using Godep, so check in our Godeps folder and the vendor folder. Note that this only works on Go 1.5 and later, with the GO15VENDOREXPERIMENT environment variable set to 1.
| paddy@0 | 1 package devices |
| paddy@0 | 2 |
| paddy@0 | 3 import ( |
| paddy@0 | 4 "errors" |
| paddy@0 | 5 |
| paddy@0 | 6 "golang.org/x/net/context" |
| paddy@0 | 7 ) |
| paddy@0 | 8 |
| paddy@0 | 9 const ( |
| paddy@0 | 10 storerKey = "code.secondbit.org/ducky/devices.hg#Storer" |
| paddy@0 | 11 ) |
| paddy@0 | 12 |
| paddy@0 | 13 var ( |
| paddy@0 | 14 // ErrNoStorerSet is returned when the Context has no Storer set in it. |
| paddy@0 | 15 ErrNoStorerSet = errors.New("storerKey not set in Context") |
| paddy@0 | 16 // ErrStorerKeyNotStorer is returned when there's a value in the Context for storerKey, but it's not a Storer. |
| paddy@0 | 17 ErrStorerKeyNotStorer = errors.New("the value for storerKey does not fulfill the Storer interface") |
| paddy@0 | 18 ) |
| paddy@0 | 19 |
| paddy@0 | 20 func getStorer(c context.Context) (Storer, error) { |
| paddy@0 | 21 val := c.Value(storerKey) |
| paddy@0 | 22 if val == nil { |
| paddy@0 | 23 return nil, ErrNoStorerSet |
| paddy@0 | 24 } |
| paddy@0 | 25 storer, ok := val.(Storer) |
| paddy@0 | 26 if !ok { |
| paddy@0 | 27 return nil, ErrStorerKeyNotStorer |
| paddy@0 | 28 } |
| paddy@0 | 29 return storer, nil |
| paddy@0 | 30 } |