Agent skeleton

command/agent/agent.go

@@ -0,0 +1,33 @@
+package agent
+
+/*
+ The agent is the long running process that is run on every machine.
+ It exposes an RPC interface that is used by the CLI to control the
+ agent. The agent runs the query interfaces like HTTP, DNS, and RPC.
+ However, it can run in either a client, or server mode. In server
+ mode, it runs a full Consul server. In client-only mode, it only forwards
+ requests to other Consul servers.
+*/
+type Agent struct {
+	config *Config
+}
+
+// Create is used to create a new Agent. Returns
+// the agent or potentially an error.
+func Create(config *Config) (*Agent, error) {
+	agent := &Agent{
+		config: config,
+	}
+	return agent, nil
+}
+
+// Leave prepares the agent for a graceful shutdown
+func (a *Agent) Leave() error {
+	return nil
+}
+
+// Shutdown is used to hard stop the agent. Should be preceeded
+// by a call to Leave to do it gracefully.
+func (a *Agent) Shutdown() error {
+	return nil
+}

command/agent/command.go

@@ -1,15 +1,11 @@
 package agent
 
 import (
-	"github.com/hashicorp/logutils"
+	"fmt"
 	"github.com/mitchellh/cli"
 	"strings"
-	"time"
 )
 
-// gracefulTimeout controls how long we wait before forcefully terminating
-var gracefulTimeout = 3 * time.Second
-
 // Command is a Command implementation that runs a Serf agent.
 // The command will not end unless a shutdown message is sent on the
 // ShutdownCh. If two messages are sent on the ShutdownCh it will forcibly
@@ -17,11 +13,28 @@ var gracefulTimeout = 3 * time.Second
 type Command struct {
 	Ui         cli.Ui
 	ShutdownCh <-chan struct{}
-	args       []string
-	logFilter  *logutils.LevelFilter
 }
 
 func (c *Command) Run(args []string) int {
+	c.Ui = &cli.PrefixedUi{
+		OutputPrefix: "==> ",
+		InfoPrefix:   "    ",
+		ErrorPrefix:  "==> ",
+		Ui:           c.Ui,
+	}
+
+	conf := DefaultConfig()
+	agent, err := Create(conf)
+	if err != nil {
+		c.Ui.Error(fmt.Sprintf("Error starting agent: %s", err))
+		return 1
+	}
+	defer agent.Shutdown()
+
+	select {
+	case <-c.ShutdownCh:
+		return 0
+	}
 	return 0
 }
 
@@ -34,56 +47,12 @@ func (c *Command) Help() string {
 Usage: consul agent [options]
 
   Starts the Consul agent and runs until an interrupt is received. The
-  agent represents a single node in a cluster.
+  agent represents a single node in a cluster. An agent can also serve
+  as a server by configuraiton.
 
 Options:
 
-  -bind=0.0.0.0            Address to bind network listeners to
-  -config-file=foo         Path to a JSON file to read configuration from.
-                           This can be specified multiple times.
-  -config-dir=foo          Path to a directory to read configuration files
-                           from. This will read every file ending in ".json"
-                           as configuration in this directory in alphabetical
-                           order.
-  -encrypt=foo             Key for encrypting network traffic within Serf.
-                           Must be a base64-encoded 16-byte key.
-  -event-handler=foo       Script to execute when events occur. This can
-                           be specified multiple times. See the event scripts
-                           section below for more info.
-  -join=addr               An initial agent to join with. This flag can be
-                           specified multiple times.
-  -log-level=info          Log level of the agent.
-  -node=hostname           Name of this node. Must be unique in the cluster
-  -profile=[lan|wan|local] Profile is used to control the timing profiles used in Serf.
-						   The default if not provided is lan.
-  -protocol=n              Serf protocol version to use. This defaults to
-                           the latest version, but can be set back for upgrades.
-  -role=foo                The role of this node, if any. This can be used
-                           by event scripts to differentiate different types
-                           of nodes that may be part of the same cluster.
   -rpc-addr=127.0.0.1:7373 Address to bind the RPC listener.
-  -snapshot=path/to/file   The snapshot file is used to store alive nodes and
-                           event information so that Serf can rejoin a cluster
-						   and avoid event replay on restart.
-
-Event handlers:
-
-  For more information on what event handlers are, please read the
-  Serf documentation. This section will document how to configure them
-  on the command-line. There are three methods of specifying an event
-  handler:
-
-  - The value can be a plain script, such as "event.sh". In this case,
-    Serf will send all events to this script, and you'll be responsible
-    for differentiating between them based on the SERF_EVENT.
-
-  - The value can be in the format of "TYPE=SCRIPT", such as
-    "member-join=join.sh". With this format, Serf will only send events
-    of that type to that script.
-
-  - The value can be in the format of "user:EVENT=SCRIPT", such as
-    "user:deploy=deploy.sh". This means that Serf will only invoke this
-    script in the case of user events named "deploy".
 `
 	return strings.TrimSpace(helpText)
 }

command/agent/config.go

@@ -0,0 +1,12 @@
+package agent
+
+// Config is the configuration that can be set for an Agent.
+// Some of this is configurable as CLI flags, but most must
+// be set using a configuration file.
+type Config struct {
+}
+
+// DefaultConfig is used to return a sane default configuration
+func DefaultConfig() *Config {
+	return &Config{}
+}