Thanks Casey, good questions. As far as the verbs go, just thinking we might want to support calls other than GET at some point. For the use case stated (enriching messages from 3rd party services) GET is all we need. Probably a moot point anyways since every http library will support the different HTTP verbs.
Agreed on the caching. I will defer to those that are more familiar with the Stellar internals on what the correct approach is. I was thinking the same thing with regards to the client libraries. Apache HttpComponents is probably the safest choice but OkHttp looks nice and could reduce effort and complexity as long as it meets our requirements. On Fri, Oct 19, 2018 at 10:58 AM Casey Stella <ceste...@gmail.com> wrote: > I think it makes a lot of sense. A couple of questions: > > - What actions do you see the REST verbs corresponding to? I would > understand GET (which is in effect "evaluate an expression", right?), > but > I'm not sure about the others. > - We should probably be careful about caching stellar expressions. Not > all stellar expressions are deterministic (e.g. PROFILE_GET may not be > as > the lookback window is bound to current time). Ultimately, I think we > should probably bake whether a function is deterministic into stellar so > that *stellar* can cache where appropriate (e.g. if every part of an > expression is deterministic, then pull from cache otherwise recompute). > All of this to say, if you're going to make it configurable, IMO we > should > make it a configuration that the user passes in at request time so they > have the control over whether the expression is safe to cache or > otherwise. > > Without more compelling reasons to not do so, I'd suggest we use HTTP > Components as it's another apache project and under active > development/support. I'd also be ok with OkHttp if it's actively > maintained. > > On Fri, Oct 19, 2018 at 11:46 AM Ryan Merriman <merrim...@gmail.com> > wrote: > > > I want to open up discussion around adding a Stellar REST client > function. > > There are services available to enrich security telemetry and they are > > commonly exposed through a REST interface. The primary purpose of this > > discuss thread to collect requirements from the community and agree on a > > general architectural approach. > > > > At a minimum I see a Stellar REST client supporting: > > > > - Common HTTP verbs including GET, POST, DELETE, etc > > - Option to provide headers and request parameters as needed > > - Support for basic authentication > > - Proper request and error handling (we can discuss further how this > > should work) > > - SSL support > > - Option to use a proxy server (including authentication) > > - JSON format > > > > In addition to these functional requirements, I would also propose we > > include these performance requirements: > > > > - Provide a configurable caching layer > > - Provide a mechanism for pooling connections > > - Provide clear documentation and guidance on how to properly use this > > feature since there is a significant risk of introducing latency > issues > > > > What else would you like to see included? > > > > I think the primary architectural decision we need to make (based on the > > agreed upon requirements of course) is an appropriate Java HTTP/REST > client > > library. Ideally we choose a library that supports everything we need > > OOTB. I think the majority of the work for this feature will involve > > wrapping this library in a Stellar function and exposing the > configuration > > knobs through Metron's configuration interface (Ambari, Zookeeper, > etc). I > > have done some very light research and here is my initial list: > > > > - Apache HttpComponents - https://hc.apache.org/ > > - Has support for all of the features listed above as far as I can > tell > > - Doesn't introduce a large number of new dependencies (am I wrong > > here?) > > - Is sort of included already (we will need to upgrade from > > httpclient) > > - Lower level > > - Google HTTP Client Library for Java - > > > > > https://developers.google.com/api-client-library/java/google-http-java-client/ > > - Higher level API with pluggable components > > - Introduces dependencies (we've had issues with Guava in the past) > > - Netflix Ribbon - https://github.com/Netflix/ribbon > > - Has a lot of nice features that may be useful in the future > > - Introduces dependencies (including guava) > > - Hasn't been committed to in the last 5-6 months > > - Unirest - https://github.com/Kong/unirest-java > > - Lightweight API built on top of HttpComponents > > - Pluggable serialization library (jackson is an issue for us so > this > > is nice) > > - Also has not received a commit in a while > > - OkHttp - http://square.github.io/okhttp/ > > - Good documentation and looks easy to use > > - Actively maintained > > > > Obviously we have a lot of choices. I think it comes down to balancing > the > > tradeoff between ease of use (HttpComponents will likely require the most > > work since it is lower level) and capability. Introducing additional > > dependencies is something we should also be mindful of because our > shading > > practices. > > > > This should get us started. Let me know what you think! > > >
