worker/apiuniter: Clone uniter, fix imports

worker/apiuniter/jujuc/context.go

Index: worker/apiuniter/jujuc/context.go
=== added file 'worker/apiuniter/jujuc/context.go'
--- worker/apiuniter/jujuc/context.go	1970-01-01 00:00:00 +0000
+++ worker/apiuniter/jujuc/context.go	2013-09-10 12:21:02 +0000
@@ -0,0 +1,133 @@
+// Copyright 2012, 2013 Canonical Ltd.
+// Licensed under the AGPLv3, see LICENCE file for details.
+
+package jujuc
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"launchpad.net/juju-core/charm"
+)
+
+// Context is the interface that all hook helper commands
+// depend on to interact with the rest of the system.
+type Context interface {
+
+	// Unit returns the executing unit's name.
+	UnitName() string
+
+	// PublicAddress returns the executing unit's public address.
+	PublicAddress() (string, bool)
+
+	// PrivateAddress returns the executing unit's private address.
+	PrivateAddress() (string, bool)
+
+	// OpenPort marks the supplied port for opening when the executing unit's
+	// service is exposed.
+	OpenPort(protocol string, port int) error
+
+	// ClosePort ensures the supplied port is closed even when the executing
+	// unit's service is exposed (unless it is opened separately by a co-
+	// located unit).
+	ClosePort(protocol string, port int) error
+
+	// Config returns the current service configuration of the executing unit.
+	ConfigSettings() (charm.Settings, error)
+
+	// HookRelation returns the ContextRelation associated with the executing
+	// hook if it was found, and whether it was found.
+	HookRelation() (ContextRelation, bool)
+
+	// RemoteUnitName returns the name of the remote unit the hook execution
+	// is associated with if it was found, and whether it was found.
+	RemoteUnitName() (string, bool)
+
+	// Relation returns the relation with the supplied id if it was found, and
+	// whether it was found.
+	Relation(id int) (ContextRelation, bool)
+
+	// RelationIds returns the ids of all relations the executing unit is
+	// currently participating in.
+	RelationIds() []int
+}
+
+// ContextRelation expresses the capabilities of a hook with respect to a relation.
+type ContextRelation interface {
+
+	// Id returns an integer which uniquely identifies the relation.
+	Id() int
+
+	// Name returns the name the locally executing charm assigned to this relation.
+	Name() string
+
+	// FakeId returns a string of the form "relation-name:123", which uniquely
+	// identifies the relation to the hook. In reality, the identification
+	// of the relation is the integer following the colon, but the composed
+	// name is useful to humans observing it.
+	FakeId() string
+
+	// Settings allows read/write access to the local unit's settings in
+	// this relation.
+	Settings() (Settings, error)
+
+	// UnitNames returns a list of the remote units in the relation.
+	UnitNames() []string
+
+	// ReadSettings returns the settings of any remote unit in the relation.
+	ReadSettings(unit string) (map[string]interface{}, error)
+}
+
+// Settings is implemented by types that manipulate unit settings.
+type Settings interface {
+	Map() map[string]interface{}
+	Get(string) (interface{}, bool)
+	Set(string, interface{})
+	Delete(string)
+}
+
+// newRelationIdValue returns a gnuflag.Value for convenient parsing of relation
+// ids in ctx.
+func newRelationIdValue(ctx Context, result *int) *relationIdValue {
+	v := &relationIdValue{result: result, ctx: ctx}
+	id := -1
+	if r, found := ctx.HookRelation(); found {
+		id = r.Id()
+		v.value = r.FakeId()
+	}
+	*result = id
+	return v
+}
+
+// relationIdValue implements gnuflag.Value for use in relation commands.
+type relationIdValue struct {
+	result *int
+	ctx    Context
+	value  string
+}
+
+// String returns the current value.
+func (v *relationIdValue) String() string {
+	return v.value
+}
+
+// Set interprets value as a relation id, if possible, and returns an error
+// if it is not known to the system. The parsed relation id will be written
+// to v.result.
+func (v *relationIdValue) Set(value string) error {
+	trim := value
+	if idx := strings.LastIndex(trim, ":"); idx != -1 {
+		trim = trim[idx+1:]
+	}
+	id, err := strconv.Atoi(trim)
+	if err != nil {
+		return fmt.Errorf("invalid relation id")
+	}
+	if _, found := v.ctx.Relation(id); !found {
+		return fmt.Errorf("unknown relation id")
+	}
+	*v.result = id
+	v.value = value
+	return nil
+}