chapter-1

Chapter 1 Networking Introduction

1. Start up our Vagrant Host
2. Start Golang web server
3. Test Webserver with Curl

A client will make an HTTP request to our minimal go web server, and it will send an HTTP response with text containing "Hello". The web server runs locally inside an Ubuntu virtual machine to test the full TCP/IP stack.

1. Start up our Vagrant Host

Vagrant Install can be found here

https://app.vagrantup.com/ubuntu/boxes/xenial64

Let's start our Vagrant host.

± |master ?:3 ✗| → cd vagrant 
± |master ✓| → vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Box 'ubuntu/xenial64' could not be found. Attempting to find and install...
    default: Box Provider: virtualbox
    default: Box Version: >= 0
==> default: Loading metadata for box 'ubuntu/xenial64'
    default: URL: https://vagrantcloud.com/ubuntu/xenial64
==> default: Adding box 'ubuntu/xenial64' (v20200904.0.0) for provider: virtualbox
    default: Downloading: https://vagrantcloud.com/ubuntu/boxes/xenial64/versions/20200904.0.0/providers/virtualbox.box
Download redirected to host: cloud-images.ubuntu.com
==> default: Successfully added box 'ubuntu/xenial64' (v20200904.0.0) for 'virtualbox'!
==> default: Importing base box 'ubuntu/xenial64'...
==> default: Matching MAC address for NAT networking...
==> default: Checking if box 'ubuntu/xenial64' version '20200904.0.0' is up to date...
==> default: Setting the name of the VM: advanced_networking_code_examples_default_1599414274357_7492
==> default: Clearing any previously set network interfaces...
==> default: Preparing network interfaces based on configuration...
    default: Adapter 1: nat
==> default: Forwarding ports...
    default: 22 (guest) => 2222 (host) (adapter 1)
==> default: Running 'pre-boot' VM customizations...
==> default: Booting VM...
==> default: Waiting for machine to boot. This may take a few minutes...
    default: SSH address: 127.0.0.1:2222
    default: SSH username: vagrant
    default: SSH auth method: private key
    default:
    default: Vagrant insecure key detected. Vagrant will automatically replace
    default: this with a newly generated keypair for better security.
    default:
    default: Inserting generated public key within guest...
    default: Removing insecure key from the guest if it's present...
    default: Key inserted! Disconnecting and reconnecting using new SSH key...
==> default: Machine booted and ready!
Got different reports about installed GuestAdditions version:
Virtualbox on your host claims:   5.0.18
VBoxService inside the vm claims: 5.1.38
Going on, assuming VBoxService is correct...
[default] A Virtualbox Guest Additions installation was found but no tools to rebuild or start them.
Got different reports about installed GuestAdditions version:
Virtualbox on your host claims:   5.0.18
VBoxService inside the vm claims: 5.1.38
Going on, assuming VBoxService is correct...
Reading package lists...
Building dependency tree...
Reading state information...
Package 'virtualbox-guest-dkms' is not installed, so not removed
Package 'virtualbox-guest-x11' is not installed, so not removed
The following packages will be REMOVED:
  virtualbox-guest-utils*
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
After this operation, 2,339 kB disk space will be freed.
(Reading database ... 54304 files and directories currently installed.)
Removing virtualbox-guest-utils (5.1.38-dfsg-0ubuntu1.16.04.3) ...
Purging configuration files for virtualbox-guest-utils (5.1.38-dfsg-0ubuntu1.16.04.3) ...
Processing triggers for man-db (2.7.5-1) ...
Reading package lists...
Building dependency tree...
Reading state information...
linux-headers-4.4.0-189-generic is already the newest version (4.4.0-189.219).
linux-headers-4.4.0-189-generic set to manually installed.
The following additional packages will be installed:
  binutils cpp cpp-5 fakeroot gcc gcc-5 libasan2 libatomic1 libc-dev-bin
  libc6-dev libcc1-0 libcilkrts5 libfakeroot libgcc-5-dev libgomp1 libisl15
  libitm1 liblsan0 libmpc3 libmpx0 libquadmath0 libtsan0 libubsan0
  linux-libc-dev make manpages-dev
Suggested packages:
  binutils-doc cpp-doc gcc-5-locales gcc-multilib autoconf automake libtool
  flex bison gdb gcc-doc gcc-5-multilib gcc-5-doc libgcc1-dbg libgomp1-dbg
  libitm1-dbg libatomic1-dbg libasan2-dbg liblsan0-dbg libtsan0-dbg
  libubsan0-dbg libcilkrts5-dbg libmpx0-dbg libquadmath0-dbg glibc-doc
  make-doc
The following NEW packages will be installed:
  binutils cpp cpp-5 dkms fakeroot gcc gcc-5 libasan2 libatomic1 libc-dev-bin
  libc6-dev libcc1-0 libcilkrts5 libfakeroot libgcc-5-dev libgomp1 libisl15
  libitm1 liblsan0 libmpc3 libmpx0 libquadmath0 libtsan0 libubsan0
  linux-libc-dev make manpages-dev
0 upgraded, 27 newly installed, 0 to remove and 0 not upgraded.
Need to get 27.9 MB of archives.
After this operation, 101 MB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu xenial/main amd64 libmpc3 amd64 1.0.3-1 [39.7 kB]
Get:2 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 binutils amd64 2.26.1-1ubuntu1~16.04.8 [2,312 kB]
Get:3 http://archive.ubuntu.com/ubuntu xenial/main amd64 libisl15 amd64 0.16.1-1 [524 kB]
Get:4 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 cpp-5 amd64 5.4.0-6ubuntu1~16.04.12 [7,783 kB]
Get:5 http://archive.ubuntu.com/ubuntu xenial/main amd64 cpp amd64 4:5.3.1-1ubuntu1 [27.7 kB]
Get:6 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libcc1-0 amd64 5.4.0-6ubuntu1~16.04.12 [38.8 kB]
Get:7 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libgomp1 amd64 5.4.0-6ubuntu1~16.04.12 [55.2 kB]
Get:8 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libitm1 amd64 5.4.0-6ubuntu1~16.04.12 [27.4 kB]
Get:9 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libatomic1 amd64 5.4.0-6ubuntu1~16.04.12 [8,892 B]
Get:10 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libasan2 amd64 5.4.0-6ubuntu1~16.04.12 [265 kB]
Get:11 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 liblsan0 amd64 5.4.0-6ubuntu1~16.04.12 [105 kB]
Get:12 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libtsan0 amd64 5.4.0-6ubuntu1~16.04.12 [244 kB]
Get:13 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libubsan0 amd64 5.4.0-6ubuntu1~16.04.12 [95.3 kB]
Get:14 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libcilkrts5 amd64 5.4.0-6ubuntu1~16.04.12 [40.0 kB]
Get:15 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libmpx0 amd64 5.4.0-6ubuntu1~16.04.12 [9,762 B]
Get:16 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libquadmath0 amd64 5.4.0-6ubuntu1~16.04.12 [131 kB]
Get:17 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libgcc-5-dev amd64 5.4.0-6ubuntu1~16.04.12 [2,239 kB]
Get:18 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 gcc-5 amd64 5.4.0-6ubuntu1~16.04.12 [8,612 kB]
Get:19 http://archive.ubuntu.com/ubuntu xenial/main amd64 gcc amd64 4:5.3.1-1ubuntu1 [5,244 B]
Get:20 http://archive.ubuntu.com/ubuntu xenial/main amd64 make amd64 4.1-6 [151 kB]
Get:21 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 dkms all 2.2.0.3-2ubuntu11.8 [66.4 kB]
Get:22 http://archive.ubuntu.com/ubuntu xenial/main amd64 libfakeroot amd64 1.20.2-1ubuntu1 [25.5 kB]
Get:23 http://archive.ubuntu.com/ubuntu xenial/main amd64 fakeroot amd64 1.20.2-1ubuntu1 [61.8 kB]
Get:24 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libc-dev-bin amd64 2.23-0ubuntu11.2 [68.8 kB]
Get:25 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 linux-libc-dev amd64 4.4.0-189.219 [852 kB]
Get:26 http://archive.ubuntu.com/ubuntu xenial-updates/main amd64 libc6-dev amd64 2.23-0ubuntu11.2 [2,083 kB]
Get:27 http://archive.ubuntu.com/ubuntu xenial/main amd64 manpages-dev all 4.04-2 [2,048 kB]
Fetched 27.9 MB in 3s (7,850 kB/s)
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Setting up cpp (4:5.3.1-1ubuntu1) ...
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Setting up libgomp1:amd64 (5.4.0-6ubuntu1~16.04.12) ...
Setting up libitm1:amd64 (5.4.0-6ubuntu1~16.04.12) ...
Setting up libatomic1:amd64 (5.4.0-6ubuntu1~16.04.12) ...
Setting up libasan2:amd64 (5.4.0-6ubuntu1~16.04.12) ...
Setting up liblsan0:amd64 (5.4.0-6ubuntu1~16.04.12) ...
Setting up libtsan0:amd64 (5.4.0-6ubuntu1~16.04.12) ...
Setting up libubsan0:amd64 (5.4.0-6ubuntu1~16.04.12) ...
Setting up libcilkrts5:amd64 (5.4.0-6ubuntu1~16.04.12) ...
Setting up libmpx0:amd64 (5.4.0-6ubuntu1~16.04.12) ...
Setting up libquadmath0:amd64 (5.4.0-6ubuntu1~16.04.12) ...
Setting up libgcc-5-dev:amd64 (5.4.0-6ubuntu1~16.04.12) ...
Setting up gcc-5 (5.4.0-6ubuntu1~16.04.12) ...
Setting up gcc (4:5.3.1-1ubuntu1) ...
Setting up make (4.1-6) ...
Setting up dkms (2.2.0.3-2ubuntu11.8) ...
Setting up libfakeroot:amd64 (1.20.2-1ubuntu1) ...
Setting up fakeroot (1.20.2-1ubuntu1) ...
update-alternatives: using /usr/bin/fakeroot-sysv to provide /usr/bin/fakeroot (fakeroot) in auto mode
Setting up libc-dev-bin (2.23-0ubuntu11.2) ...
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Processing triggers for libc-bin (2.23-0ubuntu11.2) ...
Copy iso file /Applications/VirtualBox.app/Contents/MacOS/VBoxGuestAdditions.iso into the box /tmp/VBoxGuestAdditions.iso
Mounting Virtualbox Guest Additions ISO to: /mnt
mount: /dev/loop0 is write-protected, mounting read-only
Installing Virtualbox Guest Additions 5.2.38 - guest version is 5.1.38
Verifying archive integrity... All good.
Uncompressing VirtualBox 5.2.38 Guest Additions for Linux........
VirtualBox Guest Additions installer
Copying additional installer modules ...
Installing additional modules ...
VirtualBox Guest Additions: Building the VirtualBox Guest Additions kernel
modules.  This may take a while.
VirtualBox Guest Additions: To build modules for other installed kernels, run
VirtualBox Guest Additions:   /sbin/rcvboxadd quicksetup <version>
VirtualBox Guest Additions: Building the modules for kernel 4.4.0-189-generic.
update-initramfs: Generating /boot/initrd.img-4.4.0-189-generic
VirtualBox Guest Additions: Starting.
Unmounting Virtualbox Guest Additions ISO from: /mnt
==> default: Checking for guest additions in VM...
==> default: Mounting shared folders...
    default: /vagrant => /Users/strongjz/Documents/code/advanced_networking_code_examples

2. Start Golang web server

export PATH=$PATH:/usr/local/go/bin
go run web-server.go

3. Test Webserver with Curl

In a new terminal window, ssh again into the vagrant machine to execute the curl command.

vagrant@ubuntu-xenial:~$ curl -vvv localhost:8080
* Rebuilt URL to: localhost:8080/
*   Trying 127.0.0.1...
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET / HTTP/1.1
> Host: localhost:8080
> User-Agent: curl/7.47.0
> Accept: */*
> 
< HTTP/1.1 200 OK
< Date: Sun, 20 Jun 2021 19:59:52 GMT
< Content-Length: 5
< Content-Type: text/plain; charset=utf-8
< 
* Connection #0 to host localhost left intact
Hellovagrant@ubuntu-xenial:~$