From 0348b3163a67702113cd43616c59bc1e935d59d6 Mon Sep 17 00:00:00 2001
From: "Vojtech Vitek (V-Teq)" <vojtech.vitek@pressly.com>
Date: Wed, 25 Nov 2015 17:43:30 -0500
Subject: [PATCH] Implement `--only regexp` cmd option to filter hosts

---
 README.md       | 28 ++++++++++++++++++++--------
 cmd/sup/main.go | 23 ++++++++++++++++++++++-
 2 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index eb8ce58..374248b 100644
--- a/README.md
+++ b/README.md
@@ -3,25 +3,37 @@ Stack Up
 
 Stack Up is a simple deployment tool that performs given set of commands on multiple hosts in parallel. It reads Supfile, a YAML configuration file, which defines networks (groups of hosts), commands and targets.
 
-    $ sup [-f Supfile] <network> <target/command>
+    $ sup [-f Supfile] [--only <regexp>] <network> <target/command>
 
-- `<network>` - A group of hosts, eg. `dev`, `stg` and `prod`. In this case, `prod` can map to `prod1.example.com`, `prod2.example.com` and `prod3.example.com` hosts.
-- `<command>` - A named command (or set of commands) to be run remotely.
-- `<target>` - An alias to run multiple `<commands>`.
+| command/option    | description                                                                                          |
+|-------------------|------------------------------------------------------------------------------------------------------|
+| `<network>`       | Group of hosts, eg. `production` that consists of 1-N hosts.                                         |
+| `<command>`       | Name set of bash commands to be run remotely, eg `build` that triggers `docker build -t my/image .`. |
+| `<target>`        | An alias to run multiple `<commands>`, eg `deploy` that triggers `pull`, `build` and `run` commands. |
+|                   |                                                                                                      |
+| `-f Supfile`      | Custom deployment config file (YAML) for `sup`, see [example Supfile](./example/Supfile).            |
+| `--only <regexp>` | Filter `<target>` hosts by regexp string, eg `--only host1`.                                         |
 
-`sup` picks up `Supfile` config file (YAML) from the current directory (the same way as `make` picks up `Makefile`). See [example Supfile](./example/Supfile).
+## Examples:
 
-[![Sup](https://github.com/pressly/sup/blob/gif/asciinema.gif?raw=true)](https://asciinema.org/a/19742?autoplay=1)
+    $ sup prod deploy
+    $ sup --only api1 dev tail-logs
+    $ sup -f Supfile.db stg restart
 
 # Installation
 
     $ go get -u github.com/pressly/sup/cmd/sup
 
+# Demo
+
+[![Sup](https://github.com/pressly/sup/blob/gif/asciinema.gif?raw=true)](https://asciinema.org/a/19742?autoplay=1)
+
 # Development
 
-    $ clone it..
+    fork it..
+
     $ make deps
     $ make build
 
 # License
-Stack Up is licensed under the [MIT License](./LICENSE).
+Licensed under the [MIT License](./LICENSE).
diff --git a/cmd/sup/main.go b/cmd/sup/main.go
index 3668c4f..7cd4d38 100644
--- a/cmd/sup/main.go
+++ b/cmd/sup/main.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"regexp"
 	"strings"
 	"text/tabwriter"
 
@@ -16,8 +17,9 @@ var (
 	supfile          = flag.String("f", "./Supfile", "custom path to Supfile")
 	showVersionShort = flag.Bool("v", false, "print version")
 	showVersionLong  = flag.Bool("version", false, "print version")
+	onlyHosts        = flag.String("only", "", "filter hosts with regexp")
 
-	ErrCmd              = errors.New("Usage: sup [-f <Supfile>] <network> <target/command>")
+	ErrCmd              = errors.New("Usage: sup [-f <Supfile>] [--only host1] <network> <target/command>")
 	ErrUnknownNetwork   = errors.New("Unknown network")
 	ErrNetworkNoHosts   = errors.New("No hosts for a given network")
 	ErrTarget           = errors.New("Unknown target")
@@ -143,6 +145,25 @@ func main() {
 		log.Fatal(err)
 	}
 
+	// --only option to filter hosts
+	if *onlyHosts != "" {
+		expr, err := regexp.CompilePOSIX(*onlyHosts)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		var hosts []string
+		for _, host := range network.Hosts {
+			if expr.MatchString(host) {
+				hosts = append(hosts, host)
+			}
+		}
+		if len(hosts) == 0 {
+			log.Fatal(fmt.Errorf("no hosts match '%v' regexp", *onlyHosts))
+		}
+		network.Hosts = hosts
+	}
+
 	// Create new Stackup app.
 	app, err := sup.New(conf)
 	if err != nil {