From 1e3bb6b21d60973f6e2a1791583b48bad2fef71c Mon Sep 17 00:00:00 2001
From: Chelsea Holland Komlo <me@chelseakomlo.com>
Date: Wed, 18 Apr 2018 18:09:46 -0400
Subject: [PATCH] add go-discover

---
 command/agent/retry_join.go      | 17 +++++++-
 command/agent/retry_join_test.go | 70 ++++++++++++++++++++++++++++++--
 2 files changed, 83 insertions(+), 4 deletions(-)

diff --git a/command/agent/retry_join.go b/command/agent/retry_join.go
index 42f9b2ca9..bff8af279 100644
--- a/command/agent/retry_join.go
+++ b/command/agent/retry_join.go
@@ -2,6 +2,7 @@ package agent
 
 import (
 	"log"
+	"strings"
 	"time"
 )
 
@@ -33,7 +34,21 @@ func (r *retryJoiner) RetryJoin(config *Config) {
 	r.logger.Printf("[INFO] agent: Joining cluster...")
 
 	for {
-		addrs := config.Server.RetryJoin
+		var addrs []string
+
+		for _, addr := range config.Server.RetryJoin {
+			switch {
+			case strings.Contains(addr, "provider"):
+				servers, err := r.discover.Addrs(addr, r.logger)
+				if err != nil {
+					r.logger.Printf("[ERR] agent: Join error %s", err)
+				} else {
+					addrs = append(addrs, servers...)
+				}
+			default:
+				addrs = append(addrs, addr)
+			}
+		}
 
 		n, err := r.join(addrs)
 		if err == nil {
diff --git a/command/agent/retry_join_test.go b/command/agent/retry_join_test.go
index 97408e7e3..c5d635de7 100644
--- a/command/agent/retry_join_test.go
+++ b/command/agent/retry_join_test.go
@@ -5,7 +5,6 @@ import (
 	"io/ioutil"
 	"log"
 	"os"
-	"strings"
 	"testing"
 
 	"github.com/hashicorp/nomad/testutil"
@@ -67,14 +66,14 @@ func TestRetryJoin_Integration(t *testing.T) {
 type MockDiscover struct{}
 
 func (m *MockDiscover) Addrs(s string, l *log.Logger) ([]string, error) {
-	return strings.Split(s, " "), nil
+	return []string{s}, nil
 }
 func (m *MockDiscover) Help() string { return "" }
 func (m *MockDiscover) Names() []string {
 	return []string{""}
 }
 
-func TestRetryJoin_Unit(t *testing.T) {
+func TestRetryJoin_NonCloud(t *testing.T) {
 	t.Parallel()
 	require := require.New(t)
 
@@ -105,3 +104,68 @@ func TestRetryJoin_Unit(t *testing.T) {
 	require.Equal(1, len(output))
 	require.Equal("127.0.0.1", output[0])
 }
+
+func TestRetryJoin_Cloud(t *testing.T) {
+	t.Parallel()
+	require := require.New(t)
+
+	newConfig := &Config{
+		Server: &ServerConfig{
+			RetryMaxAttempts: 1,
+			RetryJoin:        []string{"provider=aws, tag_value=foo"},
+			Enabled:          true,
+		},
+	}
+
+	var output []string
+
+	mockJoin := func(s []string) (int, error) {
+		output = s
+		return 0, nil
+	}
+
+	joiner := retryJoiner{
+		discover: &MockDiscover{},
+		join:     mockJoin,
+		logger:   log.New(ioutil.Discard, "", 0),
+		errCh:    make(chan struct{}),
+	}
+
+	joiner.RetryJoin(newConfig)
+
+	require.Equal(1, len(output))
+	require.Equal("provider=aws, tag_value=foo", output[0])
+}
+
+func TestRetryJoin_MixedProvider(t *testing.T) {
+	t.Parallel()
+	require := require.New(t)
+
+	newConfig := &Config{
+		Server: &ServerConfig{
+			RetryMaxAttempts: 1,
+			RetryJoin:        []string{"provider=aws, tag_value=foo", "127.0.0.1"},
+			Enabled:          true,
+		},
+	}
+
+	var output []string
+
+	mockJoin := func(s []string) (int, error) {
+		output = s
+		return 0, nil
+	}
+
+	joiner := retryJoiner{
+		discover: &MockDiscover{},
+		join:     mockJoin,
+		logger:   log.New(ioutil.Discard, "", 0),
+		errCh:    make(chan struct{}),
+	}
+
+	joiner.RetryJoin(newConfig)
+
+	require.Equal(2, len(output))
+	require.Equal("provider=aws, tag_value=foo", output[0])
+	require.Equal("127.0.0.1", output[1])
+}