[](https://travis-ci.org/Byron/prodash)
**prodash** is a dashboard for displaying progress of concurrent applications.
It's easy to integrate thanks to a pragmatic API, and comes with a terminal user interface by default.
[](https://asciinema.org/a/315956)
## How to use…
Be sure to read the documentation at https://docs.rs/prodash, it contains various examples on how to get started.
Or run the demo application like so `cd prodash && cargo run --example dashboard`.
## Features
* fast insertions and updates for transparent progress tracking of highly concurrent programs
* a messages buffer for information about success and failure
* a terminal user interface for visualization, with keyboard controls and dynamic re-sizing
* unicode and multi-width character support
## Limitations
* it does copy quite some state each time it displays progress information and messages
* The underlying sync data structure, `dashmap`, does not document every use of unsafe
* I also evaluated `evmap`, which has 25% less uses of unsafe, but a more complex interface.
* Thus far it seemed 'ok' to use, who knows… we are getting mutable pieces of a hashmap from multiple threads,
however, we never hand out multiple handles to the same child which should make actual concurrent access to
the same key impossible.
* If there are more than 2^16 tasks
* then
* running concurrently on a single level of the tree, they start overwriting each other
* over its lifetime, even though they do not run concurrently, eventually new tasks will seem like old tasks (their ID wrapped around)
* why
* on drop, they never decrement a child count used to generate a new ID
* fix
* make the id bigger, like u32
* we should do that once there is a performance test
## Lessons Learned
* `drop()` is not garantueed to be called when the future returns Ready and is in the futures::executor::ThreadPool
* Workaround: drop and cleanup explicitly, prone to forgetting it.
* This is also why `futures::future::abortable()` works (by stopping the polling), but doesn't as cleanup is not performed,
even though it clearly would be preferred.
* fix
* Use a join handle and await it - this will drop the future properly
* `select()` might not work with complex futures - these should then be `boxed()` if `Unpin` isn't implemented.