Self-hosted CLI chat service for the cloud written in C, the client terminal interface is portable across Unix systems (Mac OS, Linux).
Check the installation notes before proceeding with the installation of both the client and server.
There are multiple reasons why I invested so much time into this endeavour, some definitely make more sense than others. In hindsight I did learn a lot about CI/CD, coding practices, why containers make sense, general sysadmin stuff, C wizardry, Unix, portability, networking, strace, tshark, cloud stuff, etc...
So let me summarize my main motivation for building a cloud deployable self-hosted chat service:
- Take control over your chat logs, and, specially, over the metadata from your chatlogs. The best way of doing that is by hosting your own chat service. Maybe your communication service provider talks about being E2E encrypted, but what do they do with all the metadata from your communications? Are they logging it? Are they maybe not logging it, but rather putting it through an algorithm to better great a targeted ad model about you, and then discarding that data? What kind of metadata are they storing? They might not have direct access to your pictures, texts and audio messages, but they definitely know when, where and with whom you are speaking. Isn't that too much already?
- If all of this resonated with you, and you still use a common chat service, well, you might want to take a look at this great article by Rohan Kumar: WhatsApp and the domestication of users
- It is nice to be able to chat with your friends from the command line:
- A CLI normally does not take much of your computer resources and the installation binaries are also quite small. Compare that to all those JS apps eating up your precious RAM.
- You can pretend to be working on your code at work using vim and tmux, while actually be chatting with your friends, while they also pretend to work on their codeat work.
The papayaChat service consists of a server, which hosts your chatlog and handles transferring information between clients, and clients which remotely connect to the server to participate in a papayaChat session.
In order to have continuous uninterrupted access to your chat session from anywhere, you should think about hosting your papayaChat server within a cloud provider, so that you can have a static IP and run the back-end as an uninterrupted daemon. You can then install the client with your session key, in as many computers you want to use to participate in a papayaChat session with your friends.
Step by step guide to install the server/daemon that will handle the chat service:
make install-server- You need sudo rights to install the daemon in your system.
- This command will create a system user named
papayachat, which will run the papayachat daemon papayachatd in the background. - The daemon's executable will be compiled and tested before being placed at
/usr/local/bin/papayachat/. - The chatlog's file can be found at
/var/lib/papayachat/. - If there is an error during the compilation or the build does not pass the networking test, the daemon will not be installed on the system.
- Change the server's configuration file (
/etc/papayachat/server.config) to suit your needs- You need sudo rights to modify the config files and server's key.
- Specify the
PORTyou would like to use for your chat service. papayachatd daemon will be listening on this port for any clients wishing to connect to the service.
- Generate a new key and place it in the configuration folder for the server
- The file should be placed on
/etc/papayachat/with the namekey - After the installation there will be a default key inside the config folder.
- The key should have the following permission rw-r----- root:papayachat, so that the daemon can read its contents
- The key should be exactly 128 characters long. It is recommended to generate it using a SHA-512 hash.
- The file should be placed on
make runto run the chat service as a daemon- You can verify that the daemon is running with the following command:
ps -ef | grep papayachatwhich should display the running process of the daemon, or withss -atwhich should display that a service is listening at thePORTyou choosed for the service.
- You can verify that the daemon is running with the following command:
make killwill stop the papayachat daemon, if it is currently running.make uninstallwill shutdown any running papayachat daemon and un-install it and any files related to both the client and the server- To upgrade to a newer version:
- Get the release you want to upgrade
make install-serverwill un-install you current server executables, chat logs and config files, and install the version from the local repo.
- If you are not being able to connect to the server, check the firewall setup of your system,
ufwsometimes blocks packages coming from clients to the server.
Step by step guide to install the client:
- Dependencies: A default Ubuntu/Debian system will throw an error while trying to compile the client, since the
ncurseslibrary tends to be missing. Runsudo apt-get install libncurses5-devto install thencurseslibrary in the system. make install-client- This command installs the client executable at
~/bin/papayachatso that afterwards by simply typingpapayachatin your terminal, the chat client should be executed. - A configuration file for the client is also installed at
~/.papayachat/client.config.
- This command installs the client executable at
- Change the client's configuration file (
~/.papayachat/client.config) to suit your needs- You should change the default username and key. And specify the port and IP address of the server running the service you want to connect to.
- You should get the key from the person administrating the papayachat server before trying to connect to the service. Otherwise, the authentication will fail (check the section about installing the server to learn more about how to create a key).
- If you have done everything right so far, reboot your terminal to definitely be able to see the papayachat executable in your path. After that, you should be able to start the client simply by running the command
papayachatin your terminal. make uninstallwill shutdown any running papayachat daemon and un-install it and any files related to both the client and the server- To upgrade to a newer version:
- Get the release you want to upgrade
make install-clientwill un-install you current client executable and config file, and install the version from the local repo.
In order to stop a, possibly, long-running instance of the back-end daemon:
- You can either simply run
make killfrom within the directory where the Makefile is, or: - Find out the PID of the daemon with
ps -ef | grep papayachat. If there is not an established connection with a client(s), there should be only a single running daemon process (every new client connection creates 2 processes). - Kill all running processes owned by papayachat (you need sudo rights for this, since the daemon and its child processes are running as system user papayachat).
Some useful tips for debugging low level system calls and/or networking issues.
Useful debugging commands for syscall profilling with strace
$ strace -f -T -o <output_file> <process_to_profile>
-f : Trace child processes as well
-T : Show relative time of syscalls
-o : Output file
-f option is necessary in all executables that use fork() to create child processes.
Capture packages with tshark. See traffic flow between server and client.
$ sudo tshark -i 1 -P -x -f "tcp port ${PORT_NUMBER}" > ${OUTPUT_FILE}
-i : Capture on interface 1 (runs smoothly in Linode)
-P : (not sure) print summary
-x : Display content of packages in hex
-f : Filter, e.g. only tcp packets on port 51000