130 lines
3 KiB
Go
130 lines
3 KiB
Go
package watch
|
|
|
|
import (
|
|
"fmt"
|
|
"io"
|
|
"sync"
|
|
|
|
"github.com/armon/consul-api"
|
|
)
|
|
|
|
// WatchPlan is the parsed version of a watch specification. A watch provides
|
|
// the details of a query, which generates a view into the Consul data store.
|
|
// This view is watched for changes and a handler is invoked to take any
|
|
// appropriate actions.
|
|
type WatchPlan struct {
|
|
Datacenter string
|
|
Token string
|
|
Type string
|
|
Exempt map[string]interface{}
|
|
|
|
Func WatchFunc
|
|
Handler HandlerFunc
|
|
LogOutput io.Writer
|
|
|
|
address string
|
|
client *consulapi.Client
|
|
lastIndex uint64
|
|
lastResult interface{}
|
|
|
|
stop bool
|
|
stopCh chan struct{}
|
|
stopLock sync.Mutex
|
|
}
|
|
|
|
// WatchFunc is used to watch for a diff
|
|
type WatchFunc func(*WatchPlan) (uint64, interface{}, error)
|
|
|
|
// HandlerFunc is used to handle new data
|
|
type HandlerFunc func(uint64, interface{})
|
|
|
|
// Parse takes a watch query and compiles it into a WatchPlan or an error
|
|
func Parse(params map[string]interface{}) (*WatchPlan, error) {
|
|
return ParseExempt(params, nil)
|
|
}
|
|
|
|
// ParseExempt takes a watch query and compiles it into a WatchPlan or an error
|
|
// Any exempt parameters are stored in the Exempt map
|
|
func ParseExempt(params map[string]interface{}, exempt []string) (*WatchPlan, error) {
|
|
plan := &WatchPlan{
|
|
stopCh: make(chan struct{}),
|
|
}
|
|
|
|
// Parse the generic parameters
|
|
if err := assignValue(params, "datacenter", &plan.Datacenter); err != nil {
|
|
return nil, err
|
|
}
|
|
if err := assignValue(params, "token", &plan.Token); err != nil {
|
|
return nil, err
|
|
}
|
|
if err := assignValue(params, "type", &plan.Type); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Ensure there is a watch type
|
|
if plan.Type == "" {
|
|
return nil, fmt.Errorf("Watch type must be specified")
|
|
}
|
|
|
|
// Look for a factory function
|
|
factory := watchFuncFactory[plan.Type]
|
|
if factory == nil {
|
|
return nil, fmt.Errorf("Unsupported watch type: %s", plan.Type)
|
|
}
|
|
|
|
// Get the watch func
|
|
fn, err := factory(params)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
plan.Func = fn
|
|
|
|
// Remove the exempt parameters
|
|
if len(exempt) > 0 {
|
|
plan.Exempt = make(map[string]interface{})
|
|
for _, ex := range exempt {
|
|
val, ok := params[ex]
|
|
if ok {
|
|
plan.Exempt[ex] = val
|
|
delete(params, ex)
|
|
}
|
|
}
|
|
}
|
|
|
|
// Ensure all parameters are consumed
|
|
if len(params) != 0 {
|
|
var bad []string
|
|
for key := range params {
|
|
bad = append(bad, key)
|
|
}
|
|
return nil, fmt.Errorf("Invalid parameters: %v", bad)
|
|
}
|
|
return plan, nil
|
|
}
|
|
|
|
// assignValue is used to extract a value ensuring it is a string
|
|
func assignValue(params map[string]interface{}, name string, out *string) error {
|
|
if raw, ok := params[name]; ok {
|
|
val, ok := raw.(string)
|
|
if !ok {
|
|
return fmt.Errorf("Expecting %s to be a string")
|
|
}
|
|
*out = val
|
|
delete(params, name)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// assignValueBool is used to extract a value ensuring it is a bool
|
|
func assignValueBool(params map[string]interface{}, name string, out *bool) error {
|
|
if raw, ok := params[name]; ok {
|
|
val, ok := raw.(bool)
|
|
if !ok {
|
|
return fmt.Errorf("Expecting %s to be a boolean")
|
|
}
|
|
*out = val
|
|
delete(params, name)
|
|
}
|
|
return nil
|
|
}
|