1 unstable release
0.1.0 | Dec 14, 2022 |
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#17 in #waiting
25KB
422 lines
waitforit
From my waitfor
app¹, this crate extracts out the functionality to wait for certain events, including:
- elapsed time
- file (non-)existence
- file updates (timestamp or file size)
- TCP host:port (un)availablity
- HTTP GET response codes
- Arbitrary user-defined (
fn() -> bool
)
Usage
waitforit
exposes the Wait
and Waits
structs. The former is some condition (eg, as above) that the user wants to wait to complete. The latter is simply a combination other conditions. Both structs expose two methods for checking their conditions:
.condition_met() -> bool
checks and (nearly immediately) returns whether the condition is met..wait(interval: Duration)
blocks until.condition_met()
is true, checking everyinterval
All Wait
conditions can be !
negated (or, when manually constructed from the Wait
enum's variant's, by specifying a not:bool
parameter). For example, the Wait::Exists
variant checks for the existence of a file (ie, .wait
will block until that file exists). When negated, it is satisfied when the file doesn't exist.
Crate Features
By default, this crate includes the ureq
and url
crates to support making HTTP requests. This increases the number of dependencies and compile time, so if you wish to disable these, you can do so in your Cargo.toml:
waitforit = { version = "0.1.0", default_features = false }
Negations
Any Wait
or Waits
value can be negated:
let foo_exists = Wait::new_file_exists("foo.txt");
let foo_doesnt_exist = !foo_exists;
This even applies to the Elapsed
variant which means the condition will be met until the elapsed duration. This may prove useful when combining with other values. For example, wait for a file to be updated in the first ten seconds, and if that doesn't happen, then wait for the file to be deleted:
let filename = "my_dataset.json"; // assumed that this file exists
let first_10sec = !Wait::new_elapsed_from_duration(Duration::from_secs(10));
let file_updated = Wait::new_file_update(filename);
let file_not_exists = !Wait::new_file_exists(filename);
// either we update the file in the first 10 sec or we wait for it to be deleted
let w = (first_10sec & file_updated) | file_not_exists;
w.wait(Duration::from_secs(1));
TODO
- Expand the
Custom
variant to beFn
or possiblyFnMut
? - Monitor running processes (possibly with
sysinfo
crate?)
Dependencies
~0–360KB
~10K SLoC