Implement target selection, autodiscovery via aggregator, implement listTargets

cmd/cli/cmd_targets.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"os"
+	"time"
+
+	pb "git.ipng.ch/ipng/nginx-logtail/proto/logtailpb"
+)
+
+func runTargets(args []string) {
+	fs := flag.NewFlagSet("targets", flag.ExitOnError)
+	sf, target := bindShared(fs)
+	fs.Usage = func() {
+		fmt.Fprintln(os.Stderr, "usage: logtail-cli targets [--target host:port] [--json]")
+		fs.PrintDefaults()
+	}
+	fs.Parse(args)
+	sf.resolve(*target)
+
+	for _, addr := range sf.targets {
+		conn, client, err := dial(addr)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "targets: cannot connect to %s: %v\n", addr, err)
+			continue
+		}
+		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+		resp, err := client.ListTargets(ctx, &pb.ListTargetsRequest{})
+		cancel()
+		conn.Close()
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "targets: %s: %v\n", addr, err)
+			continue
+		}
+
+		if sf.jsonOut {
+			type row struct {
+				QueryTarget string `json:"query_target"`
+				Name        string `json:"name"`
+				Addr        string `json:"addr"`
+			}
+			for _, t := range resp.Targets {
+				json.NewEncoder(os.Stdout).Encode(row{QueryTarget: addr, Name: t.Name, Addr: t.Addr})
+			}
+		} else {
+			if len(sf.targets) > 1 {
+				fmt.Println(targetHeader(addr, "", len(sf.targets)))
+			}
+			for _, t := range resp.Targets {
+				addrCol := t.Addr
+				if addrCol == "" {
+					addrCol = "(self)"
+				}
+				fmt.Printf("%-40s  %s\n", t.Name, addrCol)
+			}
+		}
+	}
+}