Butler News - March 2019

[Pavel Cisar]

Hi all,

after a month of hard work, we are pleased to announce the first
tangible results - Saturnin SDK milestone 1 release (v0.2). Available in
both saturnin-sdk GIT repository and PyPI (saturnin-sdk and
saturnin-sdk-examples distributions).

Milestone 1 provides basic infrastructure for creating classic services
and clients (for running in separate threads or processes). FBSP
implementation is at the current specification level (only without
direct support for SVC_ABILITIES). So far, the developer documentation
is only in the form of very carefully commented source codes.

Version 0.2 includes a command-line tool for running and testing
services (runner script) and two sample services with clients (ECHO and
ROMAN).

Roman is a very simple standalone service that returns sent text data in
which Arabic numerals are exchanged for Roman numerals.

Echo is a classic service that returns the sent data. Its protocol
includes several variations for demonstrating the various procedures for
passing data between a client and a service, as described in Appendix A.
of FBSP Specification. One of the ECHO protocol services also performs
Roman data filtering and is used to demonstrate the creation of services
that use other services. There are also tests for both services, such as
RAW tests that use "raw" FBSP client-side communication, and CLIENT
tests that use a specific service client.

You can run both services and tests with the "runner" tool. Services can
be deployed in various combinations and communication protocols.

Parameters:

-s|--service <svcname> [<protocol / addr> [<protocol / addr> ...]

Start the svcname service listening on the listed addresses (see ZMQ
documentation for details). You can also use just protocol names and
runner will pick up a default address suitable for service. Default is
"inproc" protocol. Option could be repeated. If --test is not speified,
it runs these services until terminated (by ^C for example)

-t|--test <svcname> [--raw]

Runs test for specified service. With --raw runs FBSP messaging tests
that also print details about messages exchanged. Without --raw runs
client test with "client level" information printout.

If option is used, runner stops started services and ends after test run
completes.

-r|--remote <svcname> [<protocol / addr> [<protocol / addr> ...]

Same as --service, but only defines remote service without actually
running it. Necessary to pass information about required services to
service started with --service.

Examples:

> runner --service echo --test echo raw

Launches ECHO and runs RAW tests on it (without optional ROMAN).

> runner -s echo -s roman -t echo

Launches both services in the same process (separate threads) and runs
client tests on ECHO.

> runner -s roman tcp://127.0.0.1:5001

Runs ROMAN service until terminated.

> runner -s echo -r roman tcp://127.0.0.1:5001 -t echo --raw

Runs ECHO service connected to remote ROMAN service (see above) and runs
raw test on echo.

> runner -s echo inproc tcp://127.0.0.1:5000 -s roman inproc
tcp://127.0.0.1:5001

Runs both services listening on two addresses, ECHO uses ROMAN (best
available option is used automatically, inproc in this case).

> runner -r echo tcp://127.0.0.1:500 -t echo

Run tests on remote ECHO service

Although the code, tools and examples are still rough, they are a fully
functional demonstration of the concept (in classic version, version
that will use coroutines & asyncio will internally operate in different
way).

As a side effect of this work, the FBSP specification has undergone
minor changes/extensions to error codes and protobuf definitions.

best regards
Pavel Cisar