Add default rpc address configuration option as CONSUL_RPC_ADDR env variable

Similar as in serf: https://github.com/hashicorp/serf/pull/210

command/rpc.go

@@ -2,14 +2,24 @@ package command
 
 import (
 	"flag"
+	"os"
+
 	"github.com/armon/consul-api"
 	"github.com/hashicorp/consul/command/agent"
 )
 
+// RPCAddrEnvName defines the environment variable name, which can set
+// a default RPC address in case there is no -rpc-addr specified.
+const RPCAddrEnvName = "CONSUL_RPC_ADDR"
+
 // RPCAddrFlag returns a pointer to a string that will be populated
 // when the given flagset is parsed with the RPC address of the Consul.
 func RPCAddrFlag(f *flag.FlagSet) *string {
-	return f.String("rpc-addr", "127.0.0.1:8400",
+	defaultRPCAddr := os.Getenv(RPCAddrEnvName)
+	if defaultRPCAddr == "" {
+		defaultRPCAddr = "127.0.0.1:8400"
+	}
+	return f.String("rpc-addr", defaultRPCAddr,
 		"RPC address of the Consul agent")
 }
 

command/rpc_test.go

@@ -0,0 +1,59 @@
+package command
+
+import (
+	"flag"
+	"os"
+	"testing"
+)
+
+const defaultRPC = "127.0.0.1:8400"
+
+func getParsedRPC(t *testing.T, cliRPC, envRPC string) string {
+	args := []string{}
+
+	if cliRPC != "" {
+		args = append(args, "-rpc-addr="+cliRPC)
+	}
+
+	os.Clearenv()
+	if envRPC != "" {
+		os.Setenv(RPCAddrEnvName, envRPC)
+	}
+
+	cmdFlags := flag.NewFlagSet("rpc", flag.ContinueOnError)
+	rpc := RPCAddrFlag(cmdFlags)
+
+	if err := cmdFlags.Parse(args); err != nil {
+		t.Fatal("Parse error", err)
+	}
+
+	return *rpc
+}
+
+func TestRPCAddrFlag_default(t *testing.T) {
+	rpc := getParsedRPC(t, "", "")
+
+	if rpc != defaultRPC {
+		t.Fatalf("Expected rpc addr: %s, got: %s", defaultRPC, rpc)
+	}
+}
+
+func TestRPCAddrFlag_onlyEnv(t *testing.T) {
+	envRPC := "4.4.4.4:8400"
+	rpc := getParsedRPC(t, "", envRPC)
+
+	if rpc != envRPC {
+		t.Fatalf("Expected rpc addr: %s, got: %s", envRPC, rpc)
+	}
+}
+
+func TestRPCAddrFlag_precedence(t *testing.T) {
+	cliRPC := "8.8.8.8:8400"
+	envRPC := "4.4.4.4:8400"
+
+	rpc := getParsedRPC(t, cliRPC, envRPC)
+
+	if rpc != cliRPC {
+		t.Fatalf("Expected rpc addr: %s, got: %s", cliRPC, rpc)
+	}
+}

website/source/docs/commands/force-leave.html.markdown

@@ -32,6 +32,7 @@ The following command-line options are available for this command.
 Every option is optional:
 
 * `-rpc-addr` - Address to the RPC server of the agent you want to contact
-  to send this command. If this isn't specified, the command will contact
+  to send this command. If this isn't specified, the command checks the
-  "127.0.0.1:8400" which is the default RPC address of a Consul agent.
+  CONSUL_RPC_ADDR env variable. If this isn't set, the default RPC 
+  address will be set to "127.0.0.1:8400". 
 

website/source/docs/commands/index.html.markdown

@@ -53,6 +53,8 @@ Usage: consul join [options] address ...
 
 Options:
 
-  -rpc-addr=127.0.0.1:8400  RPC address of the Consul agent.
+  -rpc-addr=127.0.0.1:8400  Address to the RPC server of the agent you want to contact
+                            to send this command. If this isn't specified, the command checks the
+                            CONSUL_RPC_ADDR env variable.
   -wan                      Joins a server to another server in the WAN pool
 ```

website/source/docs/commands/info.html.markdown

@@ -75,6 +75,7 @@ Usage: `consul info`
 The command-line flags are all optional. The list of available flags are:
 
 * `-rpc-addr` - Address to the RPC server of the agent you want to contact
-  to send this command. If this isn't specified, the command will contact
+  to send this command. If this isn't specified, the command checks the
-  "127.0.0.1:8400" which is the default RPC address of a Consul agent.
+  CONSUL_RPC_ADDR env variable. If this isn't set, the default RPC 
+  address will be set to "127.0.0.1:8400". 
 

website/source/docs/commands/join.html.markdown

@@ -38,6 +38,7 @@ The command-line flags are all optional. The list of available flags are:
   multiple datacenters.
 
 * `-rpc-addr` - Address to the RPC server of the agent you want to contact
-  to send this command. If this isn't specified, the command will contact
+  to send this command. If this isn't specified, the command checks the
-  "127.0.0.1:8400" which is the default RPC address of a Consul agent.
+  CONSUL_RPC_ADDR env variable. If this isn't set, the default RPC 
+  address will be set to "127.0.0.1:8400". 
 

website/source/docs/commands/keyring.html.markdown

@@ -46,7 +46,9 @@ The list of available flags are:
 * `-remove` - Remove the given key from the cluster. This operation may only be
   performed on keys which are not currently the primary key.
 
-* `-rpc-addr` - RPC address of the Consul agent.
+* `-rpc-addr` - Address to the RPC server of the agent you want to contact
+  to send this command. If this isn't specified, the command will contact
+  "127.0.0.1:8400" which is the default RPC address of a Consul agent.
 
 ## Output
 

website/source/docs/commands/leave.html.markdown

@@ -26,6 +26,7 @@ Usage: `consul leave`
 The command-line flags are all optional. The list of available flags are:
 
 * `-rpc-addr` - Address to the RPC server of the agent you want to contact
-  to send this command. If this isn't specified, the command will contact
+  to send this command. If this isn't specified, the command checks the
-  "127.0.0.1:8400" which is the default RPC address of a Consul agent.
+  CONSUL_RPC_ADDR env variable. If this isn't set, the default RPC 
+  address will be set to "127.0.0.1:8400". 
 

website/source/docs/commands/members.html.markdown

@@ -28,8 +28,9 @@ The command-line flags are all optional. The list of available flags are:
   about each node.
 
 * `-rpc-addr` - Address to the RPC server of the agent you want to contact
-  to send this command. If this isn't specified, the command will contact
+  to send this command.If this isn't specified, the command checks the
-  "127.0.0.1:8400 " which is the default RPC address of a Consul agent.
+  CONSUL_RPC_ADDR env variable. If this isn't set, the default RPC 
+  address will be set to "127.0.0.1:8400".
 
 * `-status` - If provided, output is filtered to only nodes matching
   the regular expression for status

website/source/docs/commands/monitor.html.markdown

@@ -30,6 +30,6 @@ The command-line flags are all optional. The list of available flags are:
   "warn", and "err".
 
 * `-rpc-addr` - Address to the RPC server of the agent you want to contact
-  to send this command. If this isn't specified, the command will contact
+  to send this command. If this isn't specified, the command checks the
-  "127.0.0.1:8400" which is the default RPC address of a Consul agent.
+  CONSUL_RPC_ADDR env variable. If this isn't set, the default RPC 
-
+  address will be set to "127.0.0.1:8400". 

website/source/docs/commands/reload.html.markdown

@@ -32,6 +32,7 @@ Usage: `consul reload`
 The command-line flags are all optional. The list of available flags are:
 
 * `-rpc-addr` - Address to the RPC server of the agent you want to contact
-  to send this command. If this isn't specified, the command will contact
+  to send this command. If this isn't specified, the command checks the
-  "127.0.0.1:8400" which is the default RPC address of a Consul agent.
+  CONSUL_RPC_ADDR env variable. If this isn't set, the default RPC 
+  address will be set to "127.0.0.1:8400".