Build remote with Mainframer

I have one laptop for daily work and one desktop which is more powerful but not possible to travel with me.

Because the project was getting more bigger and complex. I started to feel no matter how hard I tried, it still took minutes to finish. Even I just removed one line.

And that’s when I found the Mainframer.

Mainframer is a tool for you to push the project to the remote, build there and sync the result back.

Thanks to the contributors, they really save my day.

Here are my settings:

  • Remote: Ubuntu Desktop 18.04 LTS.
  • Local: MacOS 10.12.6.
  • Mainframer: v2.1.0.

I choose desktop version just because I may need to something else which will be more easier with GUI.

To simplify the steps, some trivial steps are ignored intentionally. If you face any problem during the journey, I believe google should be enough to find the solution.

Remote

Ubuntu

JAVA

  • Install Java Open JDK 1.8
$ sudo apt install openjdk-8-jdk

SSH server

  • Install SSH server
$ sudo apt-get install openssh-server

The server should be started automatically. And now you can try to connect the server locally through $ ssh user@server-name with the password.

Android Studio

// Using sed -i '1i{TEXT}' {FILE_NAME} can put text to the head of the target file.
$ sed -i '1iexport ANDROID_HOME={REMOTE_ANDROID_SDK_ROOT}' ~/.bashrc

Make sure you can build a sample project through commands without local.properties successfully, which you may not push to the remote.

Local

Generate SSH key.

$ ssh-keygen -t rsa -b 4096 -C "{REMOTE_MACHINE_USERNAME}"
// Change .pub permission, or get "UNPROTECTED PRIVATE KEY FILE!" error.
$ chmod 600 {REMOTE_MACHINE_USERNAME}.pub

SSH config

  • Append the following content to ~/.ssh/config.
Host {REMOTE_MACHINE_ALIAS}
      User {REMOTE_MACHINE_USERNAME}
      HostName {REMOTE_MACHINE_IP_OR_HOSTNAME}
      Port 22
      IdentityFile ~/.ssh/{SSH_PRIVATE_KEY_NAME}
      PreferredAuthentications publickey
      ControlMaster auto
      ControlPath /tmp/%r@%h:%p
      ControlPersist 1h

Push public key

  • Copy and push the public key to the remote through scp.
$ scp <filename>.pub <username>@<host address>
// Loging the device with username/password, and find the .pub file
$ cat <filename.pub> > ~/.ssh/authorized_keys
// Change permission for read/write
$ chmod u+rw,go= .ssh/authorized_keys

Note: You can also use the remote_machine_setup.sh to easy publish more keys with users.

Make Android project ready

  • Create a folder ./mainframer under the project root.
  • Create a file ./mainframer/config with the following content.
remote_machine={REMOTE_MACHINE_ALIAS}

For more detail, check the official document.

Dry run

bash mainframer.sh echo "It works"

If settings are correct, the project will be synced under ~/mainframer/ on the remote, and the build log may contain information about the syncing process.

What’s more

mainframer-intellij-plugin

Once you’ve done the settings on both remote and local, you can use mainframer-intellij-plugin and skip the configuration part. The plugin will do the rest.

Using Docker

If you are familiar with Docker, you can also check the post.

Troubleshoot

Network settings on the virtual machine

If you are using the virtual machine to set up the remote, you may need to set the network setting manually.

  • Find the name of the netcard

The name may diff. In this post, we will use “enp0s3“ as an example.

$ ip -c a
  • Give the specific IP

The virtual machine will be given an IP address. Start from Ubuntu 17.10, we need to use NetPlan to change the network setting. For more detail, please check the office document.

// Create one if need.
$ sudo vi /etc/netplan/50-cloud-init.yaml

// In edit mode, input settings with the following format.
---
network:
    ethernets:
        enp0s3:
            addresses: [192.168.1.10/24]
            gateway4: 192.168.1.1
            nameservers:
              addresses: [8.8.8.8,8.8.4.4]
            dhcp4: no
    version: 2
---

// Do dry try
$ sudo netplan try
// If success will have the follow message, just hit ENTER to apply automatically.
Do you want to keep these settings?
...
 
// Apply manually
$ sudo netplan apply

Passphrase for key

After set up the SSH server and deploy the local machine’s public key. You may encounter the request when you want to ssh the remote: 

Enter passphrase for key '/home/{username}/.ssh/id_rsa':

If you really never ever set any passphrase for the SSH key, you can use:

$ ssh-add -K

SDK location not found

If you use the ignore files inside the sample project on the GitHub. You may receive the following error message:

SDK location not found. Define location with sdk.dir in the local.properties file or with an ANDROID_HOME environment variable.

This may simply because you put the commands for setting the environment value at the end of .bashrc. And get ignore because:

# If not running interactively, don't do anything
case $- in
    *i*) ;;
      *) return;;
esac

Reference