Lacca v0.1.1 Lacca View Source
Link to this section Summary
Functions
Waits for the child process to exit, and returns a result struct which
includes the status code (if applicable), and any remaining data from the
stdout
or stderr
buffers for this process
Returns a specification to start this module under a supervisor
Invoked when the server is started. start_link/3
or start/3
will
block until it returns
Attempts to terminate the process immediately. Caller should expect that the process will not be gracefully terminated; similarly to calling SIGKILL on a POSIX operating system
Returns {:ok, binary}
which includes any data received from the
child's stderr
file descriptor. Note that the internal buffer is then
cleared, such that subsequent reads will not return this same data again.
Returns {:ok, binary}
which includes any data received from the
child's stdout
file descriptor. Note that the internal buffer is then
cleared, such that subsequent reads will not return this same data again.
Starts a server which will run the executable located at exec_path
with the specified command line arguments. The returned handle, of the form
{:ok, pid}
, can be used to interact w/ the program
Requests that the resin
daemon send SIGTERM
or equivalent to forcefully
terminate the running child process. This function returns immediately, and
the signal is sent asynchronously
Returns :ok
if the data has been sent to the underlying resin
daemon.
Note that this function returns immediately after having sent the packet
to the daemon, no guarantees as to the delivery to the child process are
afforded. (i.e: the child may have closed its stdin
prematurely, the child
may have exited in the interim, it may be deadlocked and not processing stdin,
etc.)
Link to this section Functions
alive?(pid) View Source
await(pid) View Source
Waits for the child process to exit, and returns a result struct which
includes the status code (if applicable), and any remaining data from the
stdout
or stderr
buffers for this process.
When this function returns pid
will have exited.
child_spec(init_arg) View Source
Returns a specification to start this module under a supervisor.
See Supervisor
.
init(opts) View Source
Invoked when the server is started. start_link/3
or start/3
will
block until it returns.
init_arg
is the argument term (second argument) passed to start_link/3
.
Returning {:ok, state}
will cause start_link/3
to return
{:ok, pid}
and the process to enter its loop.
Returning {:ok, state, timeout}
is similar to {:ok, state}
,
except that it also sets a timeout. See the "Timeouts" section
in the module documentation for more information.
Returning {:ok, state, :hibernate}
is similar to {:ok, state}
except the process is hibernated before entering the loop. See
c:handle_call/3
for more information on hibernation.
Returning {:ok, state, {:continue, continue}}
is similar to
{:ok, state}
except that immediately after entering the loop
the c:handle_continue/2
callback will be invoked with the value
continue
as first argument.
Returning :ignore
will cause start_link/3
to return :ignore
and
the process will exit normally without entering the loop or calling
c:terminate/2
. If used when part of a supervision tree the parent
supervisor will not fail to start nor immediately try to restart the
GenServer
. The remainder of the supervision tree will be started
and so the GenServer
should not be required by other processes.
It can be started later with Supervisor.restart_child/2
as the child
specification is saved in the parent supervisor. The main use cases for
this are:
- The
GenServer
is disabled by configuration but might be enabled later. - An error occurred and it will be handled by a different mechanism than the
Supervisor
. Likely this approach involves callingSupervisor.restart_child/2
after a delay to attempt a restart.
Returning {:stop, reason}
will cause start_link/3
to return
{:error, reason}
and the process to exit with reason reason
without
entering the loop or calling c:terminate/2
.
Callback implementation for GenServer.init/1
.
kill(pid) View Source
Attempts to terminate the process immediately. Caller should expect that the process will not be gracefully terminated; similarly to calling SIGKILL on a POSIX operating system.
read_stderr(pid) View Source
Returns {:ok, binary}
which includes any data received from the
child's stderr
file descriptor. Note that the internal buffer is then
cleared, such that subsequent reads will not return this same data again.
read_stdout(pid) View Source
Returns {:ok, binary}
which includes any data received from the
child's stdout
file descriptor. Note that the internal buffer is then
cleared, such that subsequent reads will not return this same data again.
start(exec_path, args) View Source
Starts a server which will run the executable located at exec_path
with the specified command line arguments. The returned handle, of the form
{:ok, pid}
, can be used to interact w/ the program.
Note that stdout
and stderr
from the process are captured inside
StringIO
buffers internally. This data will remain in-memory until
this server is either killed, or the buffers are flushed using the
respective API functions.
Errors
This method will raise ArgumentError
if the resin
daemon cannot be
found on your system's executable PATH
. The configuration key located
at :resin, :daemon_path
can be used to force this process to run the
daemon from a non-standard location.
stop_child(pid) View Source
Requests that the resin
daemon send SIGTERM
or equivalent to forcefully
terminate the running child process. This function returns immediately, and
the signal is sent asynchronously.
Use await/1
if you wish to block on the child process actually terminating.
write_stdin(pid, data) View Source
Returns :ok
if the data has been sent to the underlying resin
daemon.
Note that this function returns immediately after having sent the packet
to the daemon, no guarantees as to the delivery to the child process are
afforded. (i.e: the child may have closed its stdin
prematurely, the child
may have exited in the interim, it may be deadlocked and not processing stdin,
etc.)