ekstat is a read-only interface to the solaris/illumos libkstat(3lib).
- ekstat is implemented as an asynchronous Erlang NIF which uses
async_nif.h. - Although it started out as a port of node-kstat, it was later rewritten using parts of the C version of the kstat command line utility.
The interface is rather simple it has 4 functions:
Simply returns a new kstat handle.
{ok, Handle} = ekstat:open().Clears the snapshot and closes the kstat handle.
ok = ekstat:close(Handle).Clears the snapshot for the handle.
{ok, NumberOfInstancesCleared} = ekstat:clear(Handle).Creates a new snapshot for the handle.
{ok, NumberOfInstancesUpdated} = ekstat:update(Handle).read(Handle) -> Result
read(Handle, Class) -> Result
read(Handle, Class, Module) -> Result
read(Handle, Class, Module, Instance) -> Result
read(Handle, Class, Module, Instance, Name) -> Result
read(Handle, Class, Module, Instance, Name, Statistic) -> Result
kstat_pattern = '_' | integer() | string()
Handle = ekstat:kstat_handle()
Class = kstat_pattern()
Module = kstat_pattern()
Instance = kstat_pattern()
Name = kstat_pattern()
Statistic = kstat_pattern()
kstat_statistic = {Key::string(), Value::integer()} | {Key::string(), Value::string()}
Result = [{Class::string(), Module::string(), Instance::integer(), Name::string(), [kstat_statistic()]}]Reads data from the snapshot (possibly selectively) and returns it:
Class = "misc",
Module = "unix",
Instance = 1,
Name = "callout",
Statistic = "callout_timeouts",
Data = ekstat:read(Handle, Class, Module, Instance, Name, Statistic).
Data = [{"misc","unix",1,"callout",[{"callout_timeouts",21286}]}].Atom '_' and list "*" are special types that will match anything in that column.
Simple glob matching can be done with *, for example:
Data = ekstat:read(H, '_', '_', '_', '_', "freem*").
Data = [{"pages","unix",0,"system_pages",[{"freemem",296009}]},
{"vm","unix",0,"vminfo",[{"freemem",257625338}]}].Regular expressions are also supported in each column, for example:
Data = ekstat:read(H, '_', '_', '_', '_', "/freemem|updates/").
Data = [{"misc","unix",0,"pset",[{"updates",78926}]},
{"misc","unix",0,"sysinfo",[{"updates",790}]},
{"pages","unix",0,"system_pages",[{"freemem",296009}]},
{"vm","unix",0,"vminfo",
[{"freemem",257625338},{"updates",790}]}].Invalid regular expressions will return an error:
Error = ekstat:read(Handle, "/*/").
Error = {error,{regerror,"repetition-operator operand invalid"}}.