Skeleton framework for ec2 provider.

juju/ec2/ec2.go

Index: juju/ec2/ec2.go
=== roger.peppe@canonical.com-20111201095604-hvesngexn5mx6465 > roger.peppe@canonical.com-20111201142639-oq2jvwxovfssfcuz
=== added file 'juju/ec2/ec2.go'
--- juju/ec2/ec2.go	1970-01-01 00:00:00 +0000
+++ juju/ec2/ec2.go	2011-12-01 14:26:39 +0000
@@ -0,0 +1,102 @@
+package ec2
+
+import (
+	"fmt"
+	"launchpad.net/juju/go/juju"
+	"launchpad.net/juju/go/schema"
+	"sync"
+)
+
+func init() {
+	juju.RegisterProvider("ec2", environProvider{})
+}
+
+type checker struct{}
+
+func (checker) Coerce(v interface{}, path []string) (interface{}, error) {
+	return &providerConfig{}, nil
+}
+
+type environProvider struct{}
+
+func (environProvider) ConfigChecker() schema.Checker {
+	return checker{}
+}
+
+var _ juju.EnvironProvider = environProvider{}
+
+// providerConfig is a placeholder for any config information
+// that we will have in a configuration file.
+type providerConfig struct{}
+
+type environ struct {
+	mu       sync.Mutex
+	baseName string
+	n        int // instance count
+
+	instances map[string]*instance
+}
+
+var _ juju.Environ = (*environ)(nil)
+
+type instance struct {
+	name string
+}
+
+func (m *instance) DNSName() string {
+	return m.name
+}
+
+func (m *instance) Id() string {
+	return fmt.Sprintf("dummy-%s", m.name)
+}
+
+// Open implements juju.EnvironProvider.Open
+func (environProvider) Open(name string, config interface{}) (e juju.Environ, err error) {
+	return &environ{
+		baseName:  name,
+		instances: make(map[string]*instance),
+	}, nil
+}
+
+// Bootstrap implements juju.Environ.Bootstrap
+func (e *environ) Bootstrap() error {
+	return nil
+}
+
+// Destroy implements juju.Environ.Destroy
+func (e *environ) Destroy() error {
+	return nil
+}
+
+// StartInstance implements juju.Environ.StartInstance
+func (e *environ) StartInstance(machineId int) (juju.Instance, error) {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+	i := &instance{
+		name: fmt.Sprintf("%s-%d", e.baseName, e.n),
+	}
+	e.instances[i.name] = i
+	e.n++
+	return i, nil
+}
+
+// StopInstances implements juju.Environ.StopInstances
+func (e *environ) StopInstances(is []juju.Instance) error {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+	for _, i := range is {
+		delete(e.instances, i.(*instance).name)
+	}
+	return nil
+}
+
+func (e *environ) Instances() ([]juju.Instance, error) {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+	var is []juju.Instance
+	for _, i := range e.instances {
+		is = append(is, i)
+	}
+	return is, nil
+}