track

A real-time Twitter trend tracker in Rust.

Upon running this application, track will compare the two provided channel keywords streaming on the Twitter platform to judge a comparison of the two topics in terms of popularity and presence on the Twitter platform.

• Design
• Prerequisite
  • Key and Token
• Test
• Execution
• Installation
• To-do
• Special Thanks

air2$ track -h
Usage: track [-h] [<first track name> <second track name>]

A real-time Twitter trend tracker in Rust.

Upon running this application, track will compare the two provided
channel keywords streaming on the Twitter platform to judge
a comparison of the two topics in terms of popularity and presence
on the Twitter platform.

'twitter' and 'facebook' are the default keywords.  You can override
those through the command line arguments, e.g. 'track love food'.

Here is the list of currently supported keywords:

twitter
facebook
google
travel
art
music
photography
love
fashion
food

$ track
Twitter trend:     ######################--------------     611/1000    [00:00:10]
Facebook trend:    #######-----------------------------     186/1000    [00:00:11]

$ track love food
Love trend:        #################-------------------     457/1000    [00:00:12]
Food trend:        ##----------------------------------      52/1000    [00:00:12]

Design

Here is the high level design diagram of the track. It's based on the standard worker pattern, which runs multiple track::Workers to retrieve the specific trend through twitter-stream Rust crate and send it through the std::sync::mpsc channel to report it back to the track::Tracker aggregator. track::Tracker creates a dedicate std::thread to report the live update through indicatif Rust crate. Since the communication between track::Tracker and track::Worker is over std::sync::mpsc channel, it can easily add more workers to support multiple tracks.

But due to the [Twitter stream API] rate limiting, you can't have more than two TCP sessions from the same IP. To overcome this challenge, we'll move to the distributed design by running those workers on a different machines, as mentioned in to-do.

+---------------------------------------------------------------+
|                         indicatif crate                       |
+---------------------------------------------------------------+
+---------------------------------------------------------------+
|                          track::Tracker                       |
+---------------------------------------------------------------+
                                ^
                                |
                 +------------------------------+
                 |    std::sync::mpsc channel   |
                 +------------------------------+
                     ^                       ^
                     |                       |
+--------------------+---------+ +-----------+------------------+
| Twitter track track::Worker  | | Facebook track track::Worker |
+------------------------------+ +------------------------------+
+---------------------------------------------------------------+
|                     twitter-stream crate                      |
+---------------------------------------------------------------+

Prerequisite

Thanks to Rust's clean design, there is not much you need to make track up and running, as in those two docker files, for ArchLinux and Ubuntu18.04, respectively. Just install the standard Rust packages and you're good to go except one thing, Key and Token.

Let's take care of that quick before the party starts.

Key and Token

track uses Twitter stream APIs to track the real-time twitter trend. To do that, you need to provide the consumer key and the access token through the environment variables. You can request key and token through Twitter developer site under Apps section:

$ export TRACK_CONSUMER_KEY=your_consumer_key
$ export TRACK_CONSUMER_SECRET=your_consumer_secret
$ export TRACK_ACCESS_TOKEN=your_access_token
$ export TRACK_ACCESS_SECRET=your_access_token_secret

Test

make test is a wrapper of cargo test. I'll add more tests along the way.

$ make test
   Compiling track v0.1.1 (/home/kei/git/track)
    Finished dev [unoptimized + debuginfo] target(s) in 1.29s
     Running target/debug/deps/track-386d81d60ee5b79d

running 5 tests
test config::tests::default_tracks ... ok
test config::tests::delay_in_msec ... ok
test config::tests::sample_count ... ok
test config::tests::total_count ... ok
test event::tests::from_str ... ok

test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

     Running target/debug/deps/track-c4ec65894b1782cc

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

   Doc-tests track

running 0 tests

test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

$

Execution

make run is the wrapper of cargo run. It shows the current real-time trend of two default keywords, 'twitter' and 'facebook'.

$ make run
    Finished dev [unoptimized + debuginfo] target(s) in 0.05s
     Running `target/debug/track`
Twitter trend:     ##----------------------------------      35/1000    [00:00:19]
Facebook trend:    ####--------------------------------      85/1000    [00:00:19]
^C

Currently, track only checks the two trend simultaneously. This is because [Twitter streaming APIs] only support two concurrent TCP session from the same source, due to the rate limitting. One way to overcome this limitation is to run the workers on different machines.

Here is the netstat output while running the the modified version of track, which spawns 10 workers. As you can see, there are only two established TCP sessions created by track.

$ netstat -cntp
(Not all processes could be identified, non-owned process info
 will not be shown, you would have to be root to see it all.)
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 192.168.255.198:36486   199.59.150.42:443       ESTABLISHED 6962/target/debug/t
tcp        0      0 192.168.255.198:36488   199.59.150.42:443       ESTABLISHED 6962/target/debug/t
^C

Installation

make install will call cargo install --force --path . to install track into your default cargo executable path:

$ make install
  Installing track v0.1.1 (/home/kei/git/track)
    Updating crates.io index
    Finished release [optimized] target(s) in 0.29s
   Replacing /home/kei/.cargo/bin/track
    Replaced package `track v0.1.1 (/home/kei/git/track)` with `track v0.1.1 (/home/kei/git/track)` (executable `track`)

To-do

Here is the list of to-dos:

• More unit tests
• Graceful shutdown
• Remove keyword limit
• Responsive output for less popular keywords
• Support more than two tracks
• Documentation

Special Thanks

Thank you so much for those great crates to make track up and running!

• The book: The Rust Programming Language
• twitter-stream: A library for listening on Twitter Streaming API
• indicatif: A Rust library for indicating progress in command line apps

Happy Hacking!