Add Time Trigger API and client (#153) (#161)

This change adds a timer trigger API, client, and implementation.  Users can trigger a function with a cron-compatible string. 

This change also moves the publisher interface and webhook-based publisher implementation out of kubewatcher and into a separate `publisher` package.

fission/timetrigger.go

@@ -0,0 +1,122 @@
+/*
+Copyrigtt 2017 The Fission Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    tttp://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"text/tabwriter"
+
+	"github.com/satori/go.uuid"
+	"github.com/urfave/cli"
+
+	"github.com/fission/fission"
+)
+
+func ttCreate(c *cli.Context) error {
+	client := getClient(c.GlobalString("server"))
+
+	name := c.String("name")
+	if len(name) == 0 {
+		name = uuid.NewV4().String()
+	}
+	fnName := c.String("function")
+	if len(fnName) == 0 {
+		fatal("Need a function name to create a trigger, use --function")
+	}
+	fnUid := c.String("uid")
+	cron := c.String("cron")
+	if len(cron) == 0 {
+		fatal("Need a cron spec like '0 30 * * *', '@every 1h30m', '@hourly', use --cron")
+	}
+
+	tt := &fission.TimeTrigger{
+		Metadata: fission.Metadata{
+			Name: name,
+		},
+		Cron: cron,
+		Function: fission.Metadata{
+			Name: fnName,
+			Uid:  fnUid,
+		},
+	}
+
+	_, err := client.TimeTriggerCreate(tt)
+	checkErr(err, "create Time trigger")
+
+	fmt.Printf("trigger '%v' created\n", name)
+	return err
+}
+
+func ttGet(c *cli.Context) error {
+	return nil
+}
+
+func ttUpdate(c *cli.Context) error {
+	client := getClient(c.GlobalString("server"))
+	ttName := c.String("name")
+	if len(ttName) == 0 {
+		fatal("Need name of trigger, use --name")
+	}
+
+	tt, err := client.TimeTriggerGet(&fission.Metadata{Name: ttName})
+	checkErr(err, "get Time trigger")
+
+	newCron := c.String("cron")
+	if len(newCron) != 0 {
+		tt.Cron = newCron
+	}
+
+	_, err = client.TimeTriggerUpdate(tt)
+	checkErr(err, "update Time trigger")
+
+	fmt.Printf("trigger '%v' updated\n", ttName)
+	return nil
+}
+
+func ttDelete(c *cli.Context) error {
+	client := getClient(c.GlobalString("server"))
+	ttName := c.String("name")
+	if len(ttName) == 0 {
+		fatal("Need name of trigger to delete, use --name")
+	}
+
+	err := client.TimeTriggerDelete(&fission.Metadata{Name: ttName})
+	checkErr(err, "delete trigger")
+
+	fmt.Printf("trigger '%v' deleted\n", ttName)
+	return nil
+}
+
+func ttList(c *cli.Context) error {
+	client := getClient(c.GlobalString("server"))
+
+	tts, err := client.TimeTriggerList()
+	checkErr(err, "list Time triggers")
+
+	w := tabwriter.NewWriter(os.Stdout, 0, 0, 1, ' ', 0)
+
+	fmt.Fprintf(w, "%v\t%v\t%v\t%v\n",
+		"NAME", "CRON", "FUNCTION_NAME", "FUNCTION_UID")
+	for _, tt := range tts {
+		fmt.Fprintf(w, "%v\t%v\t%v\t%v\n",
+			tt.Metadata.Name, tt.Cron, tt.Function.Name, tt.Function.Uid)
+	}
+	w.Flush()
+
+	return nil
+}