lib, cli: Move cli struct tags and embed this datastructure

This moves over the cli `arg` struct tags which are used to generate and
parse things on the command line. Furthermore, we then embed this data
directly in our more general parser struct so that we avoid duplication.
Finally, since the data shares a common struct type, we don't need to do
the manual field-by-field copying to pull things in!

lib/main.go

@@ -73,111 +73,115 @@ type Flags struct {
 // API is not considered stable at this time, and is subject to change.
 type Config struct {
 	// Program is the name of this program, usually set at compile time.
-	Program string
+	Program string `arg:"-"` // cli should ignore
 
 	// Version is the version of this program, usually set at compile time.
-	Version string
+	Version string `arg:"-"` // cli should ignore
 
 	// Flags are some static global flags that are set at compile time.
-	Flags Flags
+	Flags Flags `arg:"-"` // cli should ignore
 
 	// Hostname to use; nil if undefined. Useful for testing multiple
 	// instances on same machine or for overriding a bad automatic hostname.
-	Hostname *string
+	Hostname *string `arg:"--hostname" help:"hostname to use"`
 
 	// Prefix passed in; nil if undefined.
-	Prefix *string
+	Prefix *string `arg:"--prefix,env:MGMT_PREFIX" help:"specify a path to the working prefix directory"`
 
 	// TmpPrefix requests a pseudo-random, temporary prefix to be used.
-	TmpPrefix bool
+	TmpPrefix bool `arg:"--tmp-prefix" help:"request a pseudo-random, temporary prefix to be used"`
 
 	// AllowTmpPrefix allows creation of a new temporary prefix if main
 	// prefix is unavailable.
-	AllowTmpPrefix bool
+	AllowTmpPrefix bool `arg:"--allow-tmp-prefix" help:"allow creation of a new temporary prefix if main prefix is unavailable"`
 
 	// NoWatch tells engine to not change graph under any circumstances.
 	// TODO: We should consider deprecating this feature.
-	NoWatch bool
+	NoWatch bool `arg:"--no-watch" help:"do not update graph under any switch events"`
 
 	// NoStreamWatch tells engine to not update graph due to stream changes.
 	// TODO: We should consider deprecating this feature.
-	NoStreamWatch bool
+	NoStreamWatch bool `arg:"--no-stream-watch" help:"do not update graph on stream switch events"`
 
 	// NoDeployWatch tells engine to not change deploys after an initial
 	// deploy.
 	// TODO: We should consider deprecating this feature.
-	NoDeployWatch bool
+	NoDeployWatch bool `arg:"--no-deploy-watch" help:"do not change deploys after an initial deploy"`
 
 	// Noop globally forces all resources into no-op mode.
-	Noop bool
+	Noop bool `arg:"--noop" help:"globally force all resources into no-op mode"`
 
 	// Sema adds a semaphore with this lock count to each resource. This is
 	// useful for reducing parallelism.
-	Sema int
+	Sema int `arg:"--sema" default:"-1" help:"globally add a semaphore to downloads with this lock count"`
 
 	// Graphviz is the output file for graphviz data.
-	Graphviz string
+	Graphviz string `arg:"--graphviz" help:"output file for graphviz data"`
 
 	// GraphvizFilter is the graphviz filter to use, such as `dot` or
 	// `neato`.
-	GraphvizFilter string
+	GraphvizFilter string `arg:"--graphviz-filter" help:"graphviz filter to use"`
 
 	// ConvergedTimeout of approximately this many seconds of inactivity
 	// means we're in a converged state; -1 to disable.
-	ConvergedTimeout int
+	ConvergedTimeout int `arg:"--converged-timeout,env:MGMT_CONVERGED_TIMEOUT" default:"-1" help:"after approximately this many seconds without activity, we're considered to be in a converged state"`
 
 	// ConvergedTimeoutNoExit means we don't exit on converged timeout.
-	ConvergedTimeoutNoExit bool
+	ConvergedTimeoutNoExit bool `arg:"--converged-timeout-no-exit" help:"don't exit on converged-timeout"`
 
 	// ConvergedStatusFile is a file we append converged status to.
-	ConvergedStatusFile string
+	ConvergedStatusFile string `arg:"--converged-status-file" help:"file to append the current converged state to, mostly used for testing"`
 
 	// MaxRuntime tells the engine to exit after a maximum of approximately
 	// this many seconds. Use 0 to disable this.
-	MaxRuntime uint
+	MaxRuntime uint `arg:"--max-runtime,env:MGMT_MAX_RUNTIME" help:"exit after a maximum of approximately this many seconds"`
 
-	// Seeds are the list of default etc client endpoints.
-	Seeds []string
+	// Seeds are the list of default etc client endpoints. If empty, it will
+	// startup a new server.
+	Seeds []string `arg:"--seeds,env:MGMT_SEEDS" help:"default etc client endpoint"`
 
-	// ClientURLs are a list of URLs to listen on for client traffic.
-	ClientURLs []string
+	// ClientURLs are a list of URLs to listen on for client traffic. Ports
+	// 2379 and 4001 are common.
+	ClientURLs []string `arg:"--client-urls,env:MGMT_CLIENT_URLS" help:"list of URLs to listen on for client traffic"`
 
 	// ServerURLs are a list of URLs to listen on for server (peer) traffic.
-	ServerURLs []string
+	// Ports 2380 and 7001 are common. Etcd now uses --peer-urls instead.
+	ServerURLs []string `arg:"--server-urls,env:MGMT_SERVER_URLS" help:"list of URLs to listen on for server (peer) traffic"`
 
 	// AdvertiseClientURLs are a list of URLs to advertise for client
-	// traffic.
-	AdvertiseClientURLs []string
+	// traffic. Ports 2379 and 4001 are common.
+	AdvertiseClientURLs []string `arg:"--advertise-client-urls,env:MGMT_ADVERTISE_CLIENT_URLS" help:"list of URLs to listen on for client traffic"`
 
 	// AdvertiseServerURLs are a list of URLs to advertise for server (peer)
-	// traffic.
-	AdvertiseServerURLs []string
+	// traffic. Ports 2380 and 7001 are common. Etcd now uses
+	// --advertise-peer-urls instead.
+	AdvertiseServerURLs []string `arg:"--advertise-server-urls,env:MGMT_ADVERTISE_SERVER_URLS" help:"list of URLs to listen on for server (peer) traffic"`
 
 	// IdealClusterSize is the ideal number of server peers in cluster. This
 	// value is only read by the initial server.
-	IdealClusterSize int
+	IdealClusterSize int `arg:"--ideal-cluster-size,env:MGMT_IDEAL_CLUSTER_SIZE" default:"-1" help:"ideal number of server peers in cluster; only read by initial server"`
 
 	// NoServer tells the engine to not let other servers peer with me.
-	NoServer bool
+	NoServer bool `arg:"--no-server" help:"do not start embedded etcd server (do not promote from client to peer)"`
 
 	// NoNetwork tells the engine to run a single node instance without
 	// clustering or opening tcp ports to the outside.
-	NoNetwork bool
+	NoNetwork bool `arg:"--no-network,env:MGMT_NO_NETWORK" help:"run single node instance without clustering or opening tcp ports to the outside"`
 
 	// NoPgp disables pgp functionality.
-	NoPgp bool
+	NoPgp bool `arg:"--no-pgp" help:"don't create pgp keys"`
 
 	// PgpKeyPath is used to import a pre-made key pair.
-	PgpKeyPath *string
+	PgpKeyPath *string `arg:"--pgp-key-path" help:"path for instance key pair"`
 
 	// PgpIdentity is the user string used for pgp identity.
-	PgpIdentity *string
+	PgpIdentity *string `arg:"--pgp-identity" help:"default identity used for generation"`
 
 	// Prometheus enables prometheus metrics.
-	Prometheus bool
+	Prometheus bool `arg:"--prometheus" help:"start a prometheus instance"`
 
 	// PrometheusListen is the prometheus instance bind specification.
-	PrometheusListen string
+	PrometheusListen string `arg:"--prometheus-listen" help:"specify prometheus instance binding"`
 }
 
 // Main is the main struct for running the mgmt logic.