objects

type Thing ¶

type Thing struct {
	Sysname   string
	MgmtIP    *types.IP `column:"ip"`
	Vlan      *int
	Placement *ThingPlacement
}

Thing is a dummy structure to illustrate the core GET/PUT/POST/DELETE API.

It mimics a common pattern where an object also contains its own name.

We use a tag to inform gondulapi/db that MgmtIP is mapped to the "ip" column in the database.

Special note here: The only way for Go to distinguish between "The variable was not provided" and "the variable was provided, but set to the zero-value" is if the field is a pointer. That means that if Vlan is a nil-pointer in Put, the client didn't specify it and we should not modify it. If, however, it is a allocated, pointing to int<0>, it was provided, but set to 0. This is important: If you change Vlan to "Vlan int" instead of "Vlan *int", two things will happen:

1. If a client doesn't provide vlan on an update with PUT, we will still set it to 0.

2. If a row in the database has vlan set to NULL, we will fail to scan that since NULL can not be converted into an int.

In general, that means you want pointers.

It also implies that you should use constraints on your database to ensure that the values are legal. Set NOT NULL if it shouldn't be null. Set default values if it's OK to omit it on INSERT, and so on.

func (b Thing) Delete(element string) error

func (b *Thing) Get(element string) error

func (b Thing) Post() error

func (b Thing) Put(element string) error

type ThingPlacement ¶

type ThingPlacement struct {
	X1 int
	X2 int
	Y1 int
	Y2 int
}

ThingPlacement illustrates nested data structures which are implicitly handled, and, also mimicks the placement logic of switches in Gondul, which use an X1/X2 Y1/Y2 coordinate system to determine left-most and right-most X and top-most and bottom-most Y.

Please note that Postgresql will always place the upper right corner first - so X1/Y1 might be X2/Y2 when you read it back out - but the semantics are correct.

func (tp *ThingPlacement) Scan(src interface{}) error

func (tp ThingPlacement) Value() (driver.Value, error)

type Things ¶ added in v0.0.6

type Things []Thing

Things demonstrates how to fetch multiple items at the same time.

func (b *Things) Get(element string) error