luci-go: Improving setup instructions in README.md

quicksetup-infra-go-area.sh

+#!/bin/bash
+# Copyright 2015 The LUCI Authors. All rights reserved.

[tandrii(chromium), 2016/06/16 18:30:45]

nit2016

[mithro, 2016/06/17 05:05:35]

Done.

+# Use of this source code is governed under the Apache License, Version 2.0
+# that can be found in the LICENSE file.
+
+set -e
+
+mkdir cr-infra-go-area
+cd cr-infra-go-area
+
+# Download depot_tools
+echo "Getting Chromium depot_tools.."
+git clone https://chromium.googlesource.com/chromium/tools/depot_tools.git depot_tools
+echo
+
+echo "Fetching the infra build..."
+"$PWD/depot_tools/fetch" infra
+
+echo "Creating enter script..."
+# Create a bashrc include file
+ENTER_SCRIPT=$PWD/enter-env.sh
+cat > $ENTER_SCRIPT <<EOF
+#!/bin/bash
+[[ "\${BASH_SOURCE[0]}" != "\${0}" ]] && SOURCED=1 || SOURCED=0
+if [ \$SOURCED = 0 ]; then
+        exec bash --init-file $ENTER_SCRIPT
+fi
+
+if [ -f ~/.bashrc ]; then . ~/.bashrc; fi
+
+export DEPOT_TOOLS="$PWD/depot_tools"
+export PATH="\$DEPOT_TOOLS:\$PATH"
+export PS1="[cr-infra-go-area] \$PS1"
+
+cd $PWD/infra/go
+eval \$($PWD/infra/go/env.py)
+
+echo "Entered cr-infra-go-area setup at '$PWD'"
+cd "$PWD/infra/go/src/github.com/luci/luci-go"
+EOF
+chmod a+x $ENTER_SCRIPT
+
+# Running the env setup for the first time
+source $ENTER_SCRIPT
+
+# Output usage instructions
+if [ -d ~/bin ]; then
+        ln -sf $ENTER_SCRIPT ~/bin/cr-infra-go-area-enter
+        if which cr-infra-go-area-enter; then
+                echo "Enter the environment by running 'cr-infra-go-area-enter'"
+                exit 0
+        fi
+fi
+echo "Enter the environment by running '$PWD/enter-env.sh'"