config: add agent config flag for enterprise clients to indicate they wish to join a particular partition (#10572)

.changelog/10572.txt

@@ -0,0 +1,3 @@
+```release-note:feature
+config: add agent config flag for enterprise clients to indicate they wish to join a particular partition
+```

agent/config/builder_oss.go

@@ -25,6 +25,9 @@ func validateEnterpriseConfigKeys(config *Config) []error {
 	if len(config.Segments) > 0 {
 		add("segments")
 	}
+	if stringVal(config.Partition) != "" {
+		add("partition")
+	}
 	if stringVal(config.Autopilot.RedundancyZoneTag) != "" {
 		add("autopilot.redundancy_zone_tag")
 	}

agent/config/config.go

@@ -290,6 +290,8 @@ type Config struct {
 	SegmentName *string `mapstructure:"segment"`
 	// Enterprise Only
 	Segments []Segment `mapstructure:"segments"`
+	// Enterprise Only
+	Partition *string `mapstructure:"partition"`
 
 	// Enterprise Only - not user configurable
 	LicensePollBaseTime   *string `mapstructure:"license_poll_base_time"`

agent/config/runtime_oss.go

@@ -3,3 +3,5 @@
 package config
 
 type EnterpriseRuntimeConfig struct{}
+
+func (c *RuntimeConfig) PartitionOrEmpty() string { return "" }

agent/config/runtime_oss_test.go

@@ -2,6 +2,14 @@
 
 package config
 
+import (
+	"fmt"
+	"os"
+	"testing"
+
+	"github.com/hashicorp/consul/sdk/testutil"
+)
+
 var testRuntimeConfigSanitizeExpectedFilename = "TestRuntimeConfig_Sanitize.golden"
 
 func entFullRuntimeConfig(rt *RuntimeConfig) {}
@@ -19,3 +27,55 @@ var enterpriseConfigKeyWarnings = []string{
 	enterpriseConfigKeyError{key: "acl.tokens.managed_service_provider"}.Error(),
 	enterpriseConfigKeyError{key: "audit"}.Error(),
 }
+
+// OSS-only equivalent of TestConfigFlagsAndEdgecases
+// used for flags validated in ent-only code
+func TestLoad_IntegrationWithFlags_OSS(t *testing.T) {
+	dataDir := testutil.TempDir(t, "consul")
+	defer os.RemoveAll(dataDir)
+
+	tests := []testCase{
+		{
+			desc: "partition config on a client",
+			args: []string{
+				`-data-dir=` + dataDir,
+				`-server=false`,
+			},
+			json: []string{`{ "partition": "foo" }`},
+			hcl:  []string{`partition = "foo"`},
+			expectedWarnings: []string{
+				`"partition" is a Consul Enterprise configuration and will have no effect`,
+			},
+			expected: func(rt *RuntimeConfig) {
+				rt.DataDir = dataDir
+				rt.ServerMode = false
+			},
+		},
+		{
+			desc: "partition config on a server",
+			args: []string{
+				`-data-dir=` + dataDir,
+				`-server`,
+			},
+			json: []string{`{ "partition": "foo" }`},
+			hcl:  []string{`partition = "foo"`},
+			expectedWarnings: []string{
+				`"partition" is a Consul Enterprise configuration and will have no effect`,
+			},
+			expected: func(rt *RuntimeConfig) {
+				rt.DataDir = dataDir
+				rt.ServerMode = true
+				rt.LeaveOnTerm = false
+				rt.SkipLeaveOnInt = true
+				rt.RPCConfig.EnableStreaming = true
+			},
+		},
+	}
+
+	for _, tc := range tests {
+		for _, format := range []string{"json", "hcl"} {
+			name := fmt.Sprintf("%v_%v", tc.desc, format)
+			t.Run(name, tc.run(format, dataDir))
+		}
+	}
+}

agent/config/testdata/full-config.hcl

@@ -297,6 +297,7 @@ node_meta {
 }
 node_name = "otlLxGaI"
 non_voting_server = true
+partition = ""
 performance {
     leave_drain_time = "8265s"
     raft_multiplier = 5

agent/config/testdata/full-config.json

@@ -297,6 +297,7 @@
   },
   "node_name": "otlLxGaI",
   "non_voting_server": true,
+  "partition": "",
   "performance": {
     "leave_drain_time": "8265s",
     "raft_multiplier": 5,

command/agent/agent.go

@@ -195,6 +195,9 @@ func (c *cmd) run(args []string) int {
 	ui.Info(fmt.Sprintf("       Version: '%s'", c.versionHuman))
 	ui.Info(fmt.Sprintf("       Node ID: '%s'", config.NodeID))
 	ui.Info(fmt.Sprintf("     Node name: '%s'", config.NodeName))
+	if ap := config.PartitionOrEmpty(); ap != "" {
+		ui.Info(fmt.Sprintf("     Partition: '%s'", ap))
+	}
 	ui.Info(fmt.Sprintf("    Datacenter: '%s' (Segment: '%s')", config.Datacenter, segment))
 	ui.Info(fmt.Sprintf("        Server: %v (Bootstrap: %v)", config.ServerMode, config.Bootstrap))
 	ui.Info(fmt.Sprintf("   Client Addr: %v (HTTP: %d, HTTPS: %d, gRPC: %d, DNS: %d)", config.ClientAddrs,