Summary:
You should now be able to invoke query procedures written in Python. To
test the example you can run memgraph with PYTHONPATH set to `include`.
For example, assuming you are in the root of the repo, run this command.
PYTHONPATH=$PWD/include ./build/memgraph --query-modules-directory=./query_modules/
Alternatively, you can set a symlink inside the ./query_modules to point
to `include/mgp.py`, so there's no need to set PYTHONPATH. For example,
assuming you are in the root of the repo, run the following.
cd ./query_modules
ln -s ../include/mgp.py
cd ..
./build/memgraph --query-modules-directory=./query_modules/
Depends on D207
Reviewers: mferencevic, ipaljak, dsantl
Reviewed By: ipaljak
Subscribers: buda, tlastre, pullbot
Differential Revision: https://phabricator.memgraph.io/D2708
Summary:
There's no need for so many Exception subclasses, because the root cause
is always the same.
Depends on D2700
Reviewers: mferencevic, ipaljak
Reviewed By: mferencevic, ipaljak
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2701
Summary:
With this diff you should now be able to register `example.py` and read
procedures found there. The procedures will be listed through `CALL
mg.procedures() YIELD *` query, but invoking them will raise
`NotYetImplemented`.
If you wish to test this, you will need to run the Memgraph executable
with PYTHONPATH set to the `include` directory where `mgp.py` is found.
Additionally, you need to pass `--query-modules-directory` flag to
Memgraph, such that it points to where it will find the `example.py`.
For example, when running from the root directory of Memgraph repo, the
shell invocation below should do the trick (assuming `./build/memgraph`
is where is the executable). Make sure that `./query_modules/` does not
have `example.so` built, as that may interfere with loading
`example.py`.
PYTHONPATH=$PWD/include ./build/memgraph --query-modules-directory=./query_modules/
Reviewers: mferencevic, ipaljak, llugovic
Reviewed By: mferencevic, ipaljak, llugovic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2678
Summary:
This is the Python 3.5+ version of our C API found in
include/mg_procedure.h. It should strive to be simple to use, but very
hard to misuse. The Python API avoids almost all memory management
issues found in the C API, so it is automatically less error prone.
Unfortunately, we cannot avoid the issue of having some objects being
alive only during the execution of a custom procedure. For such objects
we have a `Invalid<Object>Error` exception types. The Python API should
fairly easily check the validity because all such objects are related to
ProcCtx in some way. Our C/C++ part will push 1 instance of ProcCtx each
time a Python procedure is invoked and can therefore easily change
ProcCtx to be invalid. This can be as simple as changing the
implementation pointer of ProcCtx to NULL.
Reviewers: mferencevic, ipaljak, tlastre, dsantl, buda
Reviewed By: mferencevic, tlastre
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2650
Summary:
This simplifies the C API and reduces total allocations done when
constructing a type.
Reviewers: mferencevic, ipaljak
Reviewed By: mferencevic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2550
Summary:
The type system is modelled after "CIP2015-09-16"
https://github.com/opencypher/openCypher/blob/master/cip/1.accepted/CIP2015-09-16-public-type-system-type-annotation.adoc
This is needed for registering procedures and their signatures. The
users will be able to specify what a custom procedure accepts and
returns. All of this needs to be available for inspection during
runtime. Therefore, this diff implements printing types as a user
presentable string. In the future, we will probably want to add type
checking through these types, because openCypher requires type checking
on values passed in and returned from custom procedures.
Reviewers: mferencevic, ipaljak, dsantl
Reviewed By: mferencevic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2544
Summary:
All mgp_* symbols are exported from Memgraph executable, no other
symbols should be visible.
The primary C API header, mg_procedure.h, is now part of the
installation. Also, added a shippable query module example.
Directory `query_modules` is meant to contain sources of modules we
write and ship as part of the installation. Currently, there's only an
example module, but there may be potentially more. Some modules could
only be installed as part of the enterprise release.
For Memgraph to load custom procedures, it needs to be started with a
flag pointing to a directory with compiled shared libraries implementing
those procedures.
Reviewers: mferencevic, ipaljak, llugovic, dsantl, buda
Reviewed By: mferencevic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2538
Summary:
This makes the concrete memory resource an explicit argument in custom
procedures. Unfortunately, the API is a bit uglier but at least we don't
have to worry about threading, global state or similar. This is the
primary reason for this change as we would probably like to allow
procedures to spawn threads to compute stuff in a parallel fashion.
Reviewers: mferencevic, dsantl
Reviewed By: mferencevic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2495
Summary:
The `mg_value` is the main data type used in upcoming custom procedures. Each
custom procedure will receive arguments as an array of `mg_value` instances.
The results of custom procedures will also be built as `mg_value` instances.
We should strive to have as simple and straightforward C API for custom
procedures, because we want to limit the possibility of errors and bugs on the
user facing side. Custom procedures will run in Memgraph and as such can cause
crashes and potentially a lot of nasty stuff. The burden is on the writer of
custom procedures not to mess things up, so we should make messing things up
from the C API hard if not impossible to do.
Reviewers: mferencevic, ipaljak, dsantl
Reviewed By: mferencevic
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D2443
Summary: Skiplist - fixed support for insertion of (const T&) objects. Before only (T&&) worked.
Test Plan: Tested already with slightliy modified tests.
Reviewers: buda
Reviewed By: buda
Subscribers: pullbot, florijan, buda
Differential Revision: https://phabricator.memgraph.io/D48
Summary: storage - UnoqueObjectStore documentation improved
Test Plan: no test plan
Reviewers: sale, buda
Reviewed By: sale, buda
Subscribers: pullbot, florijan, sale, buda
Differential Revision: https://phabricator.memgraph.io/D43
Summary: Minor refactor of the union_find data structure. Testing added for union_find.
Test Plan: Manual
Reviewers: sale, buda
Reviewed By: sale, buda
Subscribers: pullbot, florijan, sale, buda
Differential Revision: https://phabricator.memgraph.io/D42
Summary: Much more serious implementation of FSWatcher
Test Plan: ctest -R fswatcher
Reviewers: dtomicevic, sale
Subscribers: buda
Differential Revision: https://phabricator.memgraph.io/D33
