add 'sync' command to sync remote split assignments with local schema

Makefile

@@ -1,6 +1,6 @@
 SHELL = /bin/sh
 
-VERSION=1.5.0
+VERSION=1.6.0
 BUILD=`git rev-parse HEAD`
 
 LDFLAGS=-ldflags "-w -s \

cmds/sync.go

@@ -0,0 +1,60 @@
+package cmds
+
+import (
+	"github.com/Betterment/testtrack-cli/schema"
+	"github.com/Betterment/testtrack-cli/serializers"
+	"github.com/Betterment/testtrack-cli/servers"
+	"github.com/Betterment/testtrack-cli/splits"
+	"github.com/spf13/cobra"
+)
+
+var syncDoc = `
+Sync the local schema TestTrack assignments with the remote production TestTrack assignments.
+`
+
+func init() {
+	rootCmd.AddCommand(syncCommand)
+}
+
+var syncCommand = &cobra.Command{
+	Use:   "sync",
+	Short: "Sync TestTrack assignments with production",
+	Long:  syncDoc,
+	Args:  cobra.NoArgs,
+	RunE: func(cmd *cobra.Command, _ []string) error {
+		return Sync()
+	},
+}
+
+// Sync synchronizes the local schema TestTrack assignments with the remote production TestTrack assignments.
+func Sync() error {
+	server, err := servers.New()
+	if err != nil {
+		return err
+	}
+
+	var splitRegistry serializers.RemoteRegistry
+	err = server.Get("api/v2/split_registry.json", &splitRegistry)
+	if err != nil {
+		return err
+	}
+
+	localSchema, err := schema.Read()
+	if err != nil {
+		return err
+	}
+
+	for ind, localSplit := range localSchema.Splits {
+		remoteSplit, exists := splitRegistry.Splits[localSplit.Name]
+		if exists {
+			remoteWeights := splits.Weights(remoteSplit.Weights)
+			localSchema.Splits[ind].Weights = remoteWeights.ToYAML()
+		}
+	}
+
+	if err := schema.Write(localSchema); err != nil {
+		return err
+	}
+
+	return nil
+}

serializers/serializers.go

@@ -45,12 +45,22 @@ type SplitYAML struct {
 	Owner   string        `yaml:"owner,omitempty"`
 }
 
-// SplitJSON is is the JSON-marshalabe representation of a Split
+// SplitJSON is the JSON-marshalabe representation of a Split
 type SplitJSON struct {
 	Name              string         `json:"name"`
 	WeightingRegistry map[string]int `json:"weighting_registry"`
 }
 
+// RemoteRegistrySplit is the JSON-marshalable representation of a server-provided split configuration
+type RemoteRegistrySplit struct {
+	Weights map[string]int `json:"weights"`
+}
+
+// RemoteRegistry is the JSON-marshalable representation of a server-provided split registry
+type RemoteRegistry struct {
+	Splits map[string]RemoteRegistrySplit `json:"splits"`
+}
+
 // SplitRetirement is the JSON and YAML-marshalable representation of a SplitRetirement
 type SplitRetirement struct {
 	Split    string `json:"split"`