We are using Django for our backend REST API and PostgreSQL as DB. Need to build a User graph which has Story as a property for recommendation system. I came across Neo4jDjango. Many answers here seem to suggest this lib. But the last commit on this was 3 years before.
Is there a upto date lib I can use to seamlessly itegerate it with Django. Using Python2.7 and Django1.11 along side with PostgreSQL, want to use Neo4j just for graph querying.
It should be able to support realtime db sync, i.e. with each row update in a model a node is added in graph.
The Neo4j web site shows some alternatives to work with Python and Neo4j. Take a look:
Neo4j Python Driver: The Neo4j Python driver is officially supported by Neo4j and connects to the database using the binary protocol. It aims to be minimal, while being idiomatic to Python. (Githib repo, Last commit 3 days ago)
Py2neo: Py2neo is a client library and comprehensive toolkit for working with Neo4j from within Python applications and from the command line. The core library has no external dependencies and has been carefully designed to be easy and intuitive to use. (Github repo, Last commit on 15 Dec 2016)
Neomodel: An Object Graph Mapper built on top of the Neo4j python driver. Familiar Django style node definitions with a powerful query API, thread safe and full transaction support. A Django plugin django_nemodel is also available. (Github repo, Last commit on 9 Jun)
Neo4jRestClient: The main goal of neo4j-rest-client was to enable Python programmers already using Neo4j locally through python-embedded, to use the Neo4j REST server. So the syntax of neo4j-rest-client’s API is fully compatible with python-embedded. However, a new syntax is introduced in order to reach a more pythonic style and to enrich the API with the new features the Neo4j team introduces. (Github repo, Last commit on 14 Jun 2016)
As you can see, the Neo4j Python Driver is the most up to date.
Related
Hey is there any way to create a channel in fabric-network using fabric-network npm package.
I found this "https://hyperledger.github.io/fabric-sdk-node/release-1.4/module-fabric-network.Gateway.html#getClient__anchor" but this is for fabric-sdk-nod 1.4 and i am working on 2.2.
didn't find any solutions.
The Fabric programming model introduced with Fabric v1.4 (fabric-network, fabric-gateway-java etc.) focus on supporting business applications to submit and evaluate (query) transactions, and to receive events. Using the Fabric CLI commands became the primary supported tool for admin operations. This approach continues with the new Fabric Gateway client API, which is the primary supported client API for Fabric v2.4 onwards, replacing the legacy SDKs:
https://github.com/hyperledger/fabric-gateway
Programmatic admin capability is something that does regularly get requested by the community and, at the time of writing, there is an effort underway to develop a new Fabric admin API separate from the client application APIs/SDKs:
https://github.com/Hyperledger-TWGC/fabric-admin-sdk
I believe the Node implementation is well advanced and usable.
Again, at the time of writing, there is an open proposal to move this to a first-class Hyperledger project:
https://github.com/hyperledger/fabric-rfcs/pull/55
my problem is I want to use Neo4j database from a C++ program and I read a lot, but still don't know, how can I start.
First I would like to make a connection between Neo4j and C++, and I would like to create nodes from the C++ program.
Anyone have an example code, or can somebody help, how can I start?
For the upcoming binary remoting protocol there's already a driver written in C, see:
page: http://cleishm.github.io/libneo4j-client/
source: https://github.com/cleishm/libneo4j-client
Please note that this will only work on Neo4j 3.0 builds. As of today, milestone-2 is the most current one. Be sure to read the release notes when working with milestones.
There are no current C/C++ Neo4j drivers targeting Neo4j 2.x that I'm aware of. (See Stefan's answer for a C driver targeting the upcoming Neo4j 3.0 release)
However, using the transactional Cypher API endpoint you should be able to use any C++ http client / JSON parser to interact with Neo4j using Cypher.
Amazon Web Services offer a number of continuous deployment and management tools such as Elastic Beanstalk, OpsWorks, Cloud Formation and Code Deploy depending on your needs. The basic idea being to facilitate code deployment and upgrade with zero downtime. They also help manage best architectural practice using AWS resources.
For simplicity lets assuming a basic architecture where you have a 2 tear structure; a collection of application servers behind a load balancer and then a persistence layer using a multi-zone RDS DB.
The actual code upgrade across a fleet of instances (app servers) is easy to understand. For a very simplistic overview the AWS service upgrades each node in turn handing connections off so the instance in question is not being used.
However, I can't understand how DB upgrades are managed. Assume that we are going from version 1.0.0 to 2.0.0 of an application and that there is a requirement to change the DB structure. Normally you would use a script or a library like Flyway to perform the upgrade. However, if there is a fleet of servers to upgrade there is a point where both 1.0.0 and 2.0.0 applications exist across the fleet each requiring a different DB structure.
I need to understand how this is actually achieved (high level) to know what the best way/time of performing the DB migration is. I guess there are a couple of ways they could be achieving this but I am struggling to see how they can do it and allow both 1.0.0 and 2.0.0 to persist data without loss.
If they migrate the DB structure with the first app node upgrade and at the same time create a cached version of the 1.0.0. Users connected to the 1.0.0 app persist using the cached version of the DB and users connected to the 2.0.0 app persist to the new migrated DB. Once all the app nodes are migrated, the cached data is merged into the DB.
It seems unlikely they can do this as the merge would be pretty complex but I can't see another way. Any pointers/help would be appreciated.
This is a common problem to encounter once your application infrastructure gets into multiple application nodes. In the olden days, you could take your application offline for "maintenance windows" during which you could:
Replace application with a "System Maintenance, back soon" page.
Perform database migrations (schema and/or data)
Deploy new application code
Put application back online
In 2015, and really for several years this approach is not acceptable. Your users expect 24/7 operation, so there must be a better way. Of course there is, the answer is a series of patterns for Database Refactorings.
The basic concept to always keep in mind is to assume you have to maintain two concurrent versions of your application, and there can be no breaking changes between these two versions. This means that you have a current application (v1.0.0) currently in production and (v2.0.0) that is scheduled to be deployed. Both these versions must work on the same schema. Once v2.0.0 is fully deployed across all application servers, you can then develop v3.0.0 that allows you to complete any final database changes.
Has anyone here successfully connected to neo4j using ColdFusion?
I was able to connect to neo4j 1.6.1 using this guide as a starting point: http://ghostednotes.com/2010/04/29/using-neo4j-graph-databases-with-coldfusion
. However, it was a short lived success. I have since uninstalled neo4j 1.6.1 and installed 1.7.
I am now running Apache, CF 9.0.1 on windows XP as a local dev box. I added ...\neo4j-community-1.7\lib to my CF class path and the libraries are listed in CF Server Java Class Path. neo4j is running fine, as I can use their administrator interface: http://localhost:7474/webadmin/# . CF and Apache are also running fine. I use them daily.
While the code below works, I'd really like to 'see' what's going on using the neo4j web admininistrator. So I can coordinate my learning neo4j while using the data in a CF application.
Code: (Works)
dbroot = "/tmp/neo4jtest1/";
graphDb = createObject('java', 'org.neo4j.kernel.EmbeddedGraphDatabase');
graphDb.init( dbroot & 'var/myFirstGraphDB');
So I tried to connect to the neo4j db graph.db . However the code fails.
Code: (fails)
graphDb = createObject('java', 'org.neo4j.kernel.EmbeddedGraphDatabase');
graphDb.init( dbroot & 'graph.db');
Error:
Object instantiation exception.
An exception occurred while instantiating a Java object. The class must not be an interface or an abstract class. Error: ''.
If I remove the "." in graph.db it does create a "graphdb" in the neo4j data folder, and successfully connects to it. However, that db is not viewable with their admin :(
I'm a novice, so please dumb down your answer.
Ok, I think what you're trying to achieve is not possible. It is not possible to access Neo4J within CF (via Java) and have the admin interface working (caveat 1 applies).
If you have put all the jars of the Neo4J package into Adobe CF then most likely the Neo4J admin interface is looking at it's own Neo4J file system. When you create the Embedded server it is not connecting to the same database because it simply can't.
Embedded Neo4J doesn't work like a standard database connection. One Embedded Neo4J reads and writes to one directory location (key word: directory, it doesn't open a single file but a whole bunch of them). No two Neo4J instances can access the same directory location (caveat 2 applies).
Ok, the caveats:
1- it is possible, in theory, to manually start up the admin interface programatically so that it uses the Embedded server that you create via Java. The Java code looks simple enough (taken from Using the server (including web administration) with an embedded database):
// Create your embedded graph db somewhere
src = CreateObject("java", "org.neo4j.server.WrappingNeoServerBootstrapper")
.init(graphDb);
srv.start();
// The server is now running
// until we stop it:
srv.stop();
I did not get this working, mostly because the admin server hasa bunch of dependencies that were incompatible with the rest of my setup, so I can't advise on how well the above will work.
2- it is possible to have 1 read/write Neo4J accessing one location and then have multiple read-only Neo4Js (EmbeddedReadOnlyGraphDatabase) reading the same location (but I've never tried it).
You do have the option of using the REST interface - either manually, or via the Neo4J Java REST Binding (kinda slow, though).
It might be worth reading the Deployment Scenarios documentation before getting too deep in this.
There is at least one CF/Neo4J bridge out there, but it's pretty incomplete. I have one that I worked on, but I need to figure out if I can open source it!
Just a small addition to otupman's comments. I can confirm his theory of connecting to the admin interface from CF. Adding the following jars to the CF class path seemed to be enough to get the basics up and running. You may need additional jars if you are using more advanced features. Note, I am using Tomcat so the exact jars may differ slightly for your environment
neo4j-community-1.7/lib/*.* (entire directory)
neo4j-community-1.7/system/lib: (ONLY the jars below)
asm-3.1.jar
asm-analysis-3.2.jar
asm-commons-3.2.jar
asm-tree-3.2.jar
asm-util-3.2.jar
commons-configuration-1.6.jar
jackson-core-asl-1.8.3.jar
jackson-jaxrs-1.8.3.jar
jackson-mapper-asl-1.8.3.jar
jersey-core-1.9.jar
jersey-multipart-1.9.jar
jersey-server-1.9.jar
jetty-6.1.25.jar
jetty-util-6.1.25.jar
neo4j-server-1.7-static-web.jar
neo4j-server-1.7.jar
rrd4j-2.0.7.jar
Then started the server and database in onApplicationStart
factory = createObject("java", "org.neo4j.graphdb.factory.GraphDatabaseFactory");
dbroot = ExpandPath("/neo4jtest/");
graphDb = factory.newEmbeddedDatabase(dbroot & 'myFirstGraphDB');
Bootstrapper = createObject("java", "org.neo4j.server.WrappingNeoServerBootstrapper");
graphServer = Bootstrapper.init( graphDb );
graphServer.start();
application.graphServer = graphServer;
application.graphDb = graphDB;
And closed both in onApplicationEnd
application.graphDb.shutDown();
application.graphServer.stop();
Edit: After some further testing, I think is better to load them once in OnServerStart. Then use a shutdown hook to close them. But since this is just for a local development box, it is less critical.
I'm interested in using libdrizzle as a generic asynchronous-capable connector for mysql db for a c++ application (actually as a backend for hiberlite). Since early this year libdrizzle is no longer a separate project and its merged in the same drizzle project, so installing as a separate dependency (unrelated to the rest of drizzle) might have become slightly more complex.
I'm wondering if people has used this library for interfacing to MySql or MariaDB, probably make some mickey mouse benchmarks to have a rough idea how it stands relative to the synchronous default driver.
Also, comments on difficulties to install, setup, pitfalls (the documentation is essentially nonexistent) would be greatly appreciated.
You might want to take a look at ngx_drizzle (drizzle-nginx-module) at github.
From module description:
This is an nginx upstream module integrating libdrizzle into Nginx in a non-blocking and streamming way.
Essentially it provides a very efficient and flexible way for nginx internals to access MySQL, Drizzle, as well as other RDBMS's that support the Drizzle or MySQL wired protocol. Also it can serve as a direct REST interface to those RDBMS backends.
If you're using MySQL, then MySQL 5.0 ~ 5.5 is required. We're not sure if MySQL 5.6+ work; reports welcome!