bract.core.util — bract/bract.core 0.6.2-beta2

Standalone utility functions.

alive-millis clj

(alive-millis)

(alive-millis n)

Return a function (fn []) that when invoked, records the current time as when was the application last alive. You may deref the same function as (deref f) to find out the time the application was last alive. Optimized for concurrent updates; eventually consistent.

as-str clj

(as-str x)

Turn anything into string.

as-vec clj

(as-vec x)

Turn argument into a vector if it is a collection, else wrap the argument into a single-item vector.

clean-uuid clj

(clean-uuid)

(clean-uuid uuid)

Generate or convert UUID into a sanitized, lower-case form.

err-print-banner clj

(err-print-banner x & more)

Print a banner to *err*.

err-println clj

(err-println x & more)

Same as clojure.core/println for *err*.

exec-once! clj macro

(exec-once! a-var & body)

Given a redefinable var e.g. (defonce a-var nil) having logical false value, set it to true and evaluate the body.

expected clj

(expected expectation found)

(expected pred expectation found)

Throw illegal input exception citing expectation and what was found did not match. Optionally accept a predicate fn to test found before throwing the exception.

health-status clj

(health-status components)

Given a collection of health status maps (with keys :status and :impact) of zero or more components, derive overall health status and return status map {:status status :components components} based on the following rules:

0. Health status :critical > :degraded > :healthy (high to low)

1. Higher old-status always overrides lower new-status.

2. Same old-status and new-status are considered unchanged.

3. A higher new-status is interpreted as follows:

   Old status	New status	Impact :direct	Impact :indirect	Impact :noimpact
   degraded	critical	critical	degraded	degraded
   healthy	critical	critical	degraded	healthy
   healthy	degraded	degraded	degraded	healthy

Example of returned status:

{:status :degraded  ; derived from components - :critical, :degraded, :healthy (default), :unknown
 :components [{:id     :mysql
               :status :degraded
               :impact :hard    ; impact on overall health - :hard (default), :soft, :none/nil/false
               :breaker :half-open
               :retry-in "14000ms"}
              {:id     :cache
               :status :critical
               :impact :soft}
              {:id     :disk
               :status :healthy
               :impact :none
               :free-gb 39.42}]}

invoke clj

(invoke f & args)

Invoke first argument as a function on the remaining arguments.

let-var clj macro

(let-var bindings & body)

Given a binding vector where right-hand side is fully-qualified var name symbol and body of code, resolve the vars and evaluate the body of code in the binding context.

millis->str clj

(millis->str millis)

Convert milliseconds to human readable string.

nbytes->str clj

(nbytes->str n)

Convert bytes-count to human readable string.

now-millis clj

(now-millis)

(now-millis start-millis)

Return current epochal time in milliseconds.

pst-when-uncaught-handler clj

(pst-when-uncaught-handler e)

(pst-when-uncaught-handler e out)

When uncaught exception handler is configured, print the stack trace.

set-default-uncaught-exception-handler clj

(set-default-uncaught-exception-handler f)

Set specified function (fn [thread throwable]) as default uncaught exception handler.

shorten-name clj

(shorten-name any-name)

(shorten-name split-regex any-name)

Shorten a stringable name, e.g. foo.bar.baz.qux/fred to f.b.baz.qux/fred, leaving only the last two tokens intact.

sleep-millis clj

(sleep-millis millis)

Sleep for specified number of milliseconds.

stack-trace-str clj

(stack-trace-str e)

Given a throwable (generally an exception) return the stack trace string as it would be printed on a console.