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nodeSolidServer / node-solid-server

Solid server on top of the file-system in NodeJS
https://solidproject.org/for-developers/pod-server
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Is refactoring or rewriting the most efficient and cost-effective way to realize a high-quality and robust codebase for NSS? #788

Closed kjetilk closed 5 years ago

kjetilk commented 6 years ago

Unfortunately, we didn't manage to have full attendance for our meeting in Boston where we discussed the choice of refactoring this module, vs rewriting it from scratch with a deliberate architecture. It has become a recurrent conversation on gitter, but I feel those conversations have not been very productive due to the constraints of the chat as a medium. Perhaps a github issue is better suited for that conversation. For us developers, I think it is very important we can have a resolution to this.

kjetilk commented 6 years ago

A useful starting point is the document that @RubenVerborgh produced for the Boston meeting, and that him, I and @justinwb formed consensus around. I'll paste it here since @RubenVerborgh is travelling, and so that we have everything in one place:

Purpose: this document details why the node-solid-server v4/v5 code should be considered end-of-life, and why we should consider a rewrite rather than a refactoring for v6. Furthermore, it details a high-level timeline and approach for such a rewrite.

Status: 2018-08-24: drafted by Ruben Verborgh, open for comments 2018-09-20: Edited and amended by Kjetil Kjernsmo for suitability as a github issue.

1. Major issues with the current code-base

1.1 Lack of architecture and interfaces

Issue

The server had no upfront architecture, and the current code has organically grown.

Consequences

The resulting code structure is very difficult and hard to maintain. Changing components is hard, for instance:

1.2 Components use in-depth knowledge about each other

Issue

Consequences

Example

1.3 Violations of single-responsibility

Issue

One piece of knowledge/functionality is encoded in multiple places

Consequences

Example

The mapping between a URL and the filesystem is implemented in multiple places.

1.4 Abundance of global state

Issue

1.5 Lack of testability

Issue

1.6 Varying coding styles and quality (minor)

Issue

Consequences

2. Conclusion: a rewrite is needed

Given all of the above, we conclude that:

3. Proposed timeline

4. Approach to new server development

In order to avoid encountering the same problems of v4/v5 again, we should:

  1. Have an up-front vertical architecture
    1. https://github.com/solid/solid-architecture/blob/master/server/request-flow.md can be used as guidance
  2. Have a clear horizontal architecture
    1. This will enforce interfaces between components
    2. It could also ensure composeability of components to ensure easier changes in backend behavior.
    3. We should consider using TypeScript to enforce these interfaces
    4. An example prototype is available at https://github.com/RubenVerborgh/solid-server-ts
  3. Have sufficient test coverage
    1. Unit tests for individual components If something is not unit-testable, this points to a problem with the code structure / architecture.
    2. HTTP-level system tests in a separate repository, that test Solid servers regardless of the underlying implementation
RubenVerborgh commented 6 years ago
  • using different backend storage (Amazon S3, triplestores, hybrid, …, see #702 however),

I think #702 actually makes a very good case for a rewrite. Dmitri is doing hard work, but #702 is nowhere near finished—it doesn't even touch any LDP code yet. Based on the above I would make the case that doing #702 in a stable way will require more effort through a refactor than through a rewrite.

elf-pavlik commented 6 years ago

Following on something I wrote in #672 - having separate OIDC provider and separate pure dataset pod or pod that also has OIDC provider feature enabled. If current architecture doesn't allow easy separation of those features I would see it as :+1: for a clean rewrite.

kjetilk commented 6 years ago

I'd like to add some perspectives:

What is hard

First, I'd like to add my experience about what is actually hard in development. In the beginning of a project, everything is somewhat nebulous and fluid, and you learn as you go, and you make the changes that seem reasonable at the time. You have all kinds of concerns and pushbacks, and you code to a changing world that you do not fully understand at any point in time. This scrambling phase is a really hard development phase to be in. Thus, my desire to rewrite is not born from being judgmental about the current code, to the contrary, I acknowledge that it was written in a different phase of the project, where they were coding to exactly these complexities. Code written under such conditions will necessarily look bad with the benefit of hindsight. That's OK, it is normal, and being efficient under such conditions is to be admired. It is true that many developers will look at other people's code with a certain disdain, but it shouldn't be taken as an argument against a rewrite, it all depends on what phase of a project the code was written in.

However, once you enter a new phase of the project, one when things aren't changing under your feet, when you have the benefit of hindsight, you aren't dealing with all kinds of concerns and pushbacks, replicating that work should normally not be very difficult.

I would normally be against big rewrites in the first phase, unless the codebase is very small. I have been to a few processes where it has been a bad idea to rewrite stuff in that phase.

I hope that the Solid project has entered that much more stable phase now, on the server side. We should know well how the server should behave now. For example, we now know which OIDC libraries are maintained, that knowledge is a luxury our predecessors didn't have.

Thus, a rewrite is not about passing judgment on the current codebase, it is just that one shouldn't be afraid to throw away code if you are in a phase where lessons already have been learned. In fact, that should be a normal thing to do in a long-duration project.

Obviously, it might be that we have not entered that phase yet, that there are still big and open issues. I suppose, https://github.com/solid/solid/issues/152 may be such an issue.

This possibility should be balanced against other problems with the codebase, however.

Experiences with refactoring vs rewrites

As mentioned above, rewrites when requirements are changing is in my experience not viable, it takes too long to get back up to parity, and when you reach parity, you will be in the same situation that you were before the rewrite started and producing code in the same environment, which is really hard.

Refactoring is also viable when there was a rough but not thorough architecture to beginning with. Then, with the benefit of hindsight and the benefit of understanding possible frameworks that the architecture could use, refactoring into a framework is something that I have advocated in the past (in a project that was rewritten, when I advocated a refactoring effort).

Experiences with NSS so far

I have not been working with NSS for very long, but I can say that it is a difficult codebase to get into, taking into the perspective that the spec is pretty simple, and something I have done much of in other code. It is due to two things, mainly; insufficient test coverage and that knowledge of the whole system is often required to understand small changes.

It is not given that a refactoring effort will take less time to do rather than a rewrite, as on-boarding will be slow, and those coming on board cannot easily draw on the experiences of the predecessors as they are not any longer working full time on the project.

I think it is very important that the server has been written by people who are likely to stay with the project for a long time. It makes little sense to retain code that has been in the difficult scrambling phase if none of those who worked at it at the time is working on it continuously.

Since the spec is fairly simple, it would be surprised if we couldn't make a rewrite much simpler than the current code. This is not about making the complicated second system, to the contrary, it is about writing a simpler and better designed system because we have the benefit of hindsight. A case in point is @timbl's rewrite of https://github.com/solid/solid-permissions into https://github.com/solid/acl-check/ where the number of lines were reduced from ~2000 to ~125. While such a reduction is unlikely, it is the kind of goals we would reasonably have.

It is not at all clear to me how one would go about to refactor the current code. I just don't see how that could be done, and so, I would challenge those that advocate refactoring the system to come forward with a concrete plan on how to do that.

We need to know what it costs

Taking another outlook, it is not unlikely that we will be writing the server again and again, since it is supposed to be pretty simple. It may be required to have the server in several languages and environments. There are already several implementations, and to get e.g. Nextcloud on board would require another PHP server that is suited for their purpose.

It may be substantial business opportunities in adapting servers for enterprise environments, and so, it is important that we have a very good understanding of what it costs to write one. The experience that the previous implementors had is not relevant to this problem, they were programming to a much more dynamic world.

Conclusion

We are not proposing a rewrite to produce a larger system, we are proposing to write a simpler system, but one that benefits from the experiences already gained. It is not given that this will be more expensive than refactoring, given that we do not know how a refactoring would look like. Very substantial changes are required to secure the server, and we also need to make the onboarding process simpler, even though we expect fewer people to work on the server side than the client side.

kjetilk commented 6 years ago

Following on something I wrote in #672 - having separate OIDC provider and separate pure dataset pod or pod that also has OIDC provider feature enabled. If current architecture doesn't allow easy separation of those features I would see it as +1 for a clean rewrite.

Yeah, I suppose it isn't that hard, but I think it is really important to get WebID-OIDC to work by a trivial addition to any compliant OIDC service.

nicola commented 6 years ago

I just want to add a piece of feedback here: I always wanted to rewrite this library! After a few months when things were changing I did want to rewrite it again, so you have a strong support from me (one of the first authors of the original library).

I think the rewrite will be much faster and much more informed today than it was then! I agree with all the points you are making, they are all very valid and really true.

During free time (back then), I ended up rewriting node solid, layering the different components (I can find it if useful), but unfortunately, I never completed it. The idea was to have an LDP library with different storage support which would provide APIs to read/write to the storage, this was wrapped in an ACL layer that would check permission and by an authentication layer that would check the identity.

The ldp library is a good starting point (and the rdf-store library with different storage support that @bergos and I made would make it a lot easier too.

melvincarvalho commented 6 years ago

@nicola thanks for the feedback! Do you have any thoughts regarding the approach

Or a combination of the above?

kjetilk commented 6 years ago

Thanks a lot, @nicola ! It is good to know that you don't just feel we're trampling on your work! As I said, you did this in a very different environment than we're going to face.

bergos commented 6 years ago

I moved already some code (parsers and serializers) to the RDFJS organization for the RDFJS library/framework. That means I removed the rdf-ext dependency and they work with the reference data model or any other RDFJS data factory. My next steps would be (ordered based on the dependencies between the libraries):

The WebID authentications should be implemented as Passport.js modules as it's the de facto standard for node authentication modules.

The mentioned ldp package uses blob-store to access files.

In general it would be good to check which libraries/frameworks/interfaces/abstraction could be used.

melvincarvalho commented 6 years ago

@RubenVerborgh @kjetilk thanks for putting this together, and the wonderful ideas for type script interfaces

@bergos thanks for the pointers! I'm also a big fan or passport.js.

Re : refactoring or rewriting, my personal take is that, first and foremost any and all code contributions to node solid server, are a huge plus, and refactoring tends to pay for itself in the longer term. Comparing the merits, refactoring has some of advantages over rewriting

A full rewrite is also a viable strategy. I see it as slightly more risky. Some rewrites are spectacularly successful. Some never make it. Whereas refactoring, by definition keeps exactly the same functionality but improves the code base for those that come after, normally in a time limited way. I can live with either path.

Some specific comments :

Maintenance fixes are still released as v5.0.x, but no more new features.

This sounds a bit like a code freeze to me. As a user, app dev, and occasional maintainer of solid systems, relevant to me is : how long would there be a feature freeze? My estimate would be a rewrite to take c. one year, and I'd be interested in the timelines of those that might like to work on this.

As soon as the server has feature parity is achieved

What would be the metric for achieving this. We dont have full test coverage on the server side, for example for command line switches (not even sure how to do that!). And barely any test coverage for apps. How will we ensure apps, and also servers, don't break upgrading from the old server to the new? We've seen in the past large companies make breaking changes to systems. That can sometimes become a talking point. Creating invisible upgrade paths helps create good will and maintains the public contract.

That said, it's not my decision to make, as others will be doing the work, but I will follow with great interest! Just my 2 cents!

RubenVerborgh commented 6 years ago

Just a small remark on

How will we ensure apps, and also servers, don't break upgrading from the old server to the new?

Note that this equally holds for refactoring and rewriting, given the current lack (and impossibly of) many unit tests.

Regarding:

Comparing the merits, refactoring has some of advantages over rewriting

You can tackle it in stages You can try to ensure regression, feature parity, add tests

This is assuming the code can be refactored, in a way that is not merely an in-place rewrite of everything. My arguments above aim suggest that this is not the case for this particular codebase.

We would need a proposal for concrete stages from someone. My opinion is that the code is too tangled for that.

You can measure progress

Same with a rewrite.

nicola commented 6 years ago

I just found my rewriting of solid is actually already on github and it is here: https://github.com/nicola/node-solid

This uses the LDP library and rdf-store

RubenVerborgh commented 6 years ago

@nicola Thanks, any assessment on completeness besides what the README says?

kjetilk commented 6 years ago

Re : refactoring or rewriting, my personal take is that, first and foremost any and all code contributions to node solid server, are a huge plus, and refactoring tends to pay for itself in the longer term. Comparing the merits, refactoring has some of advantages over rewriting

Actually, I think that is an oversimplification. The devil is in the details, and therefore I think it is really hard to say what brings most long-term benefits in the general case. I've been through both rewrites that have practically killed the product, where refactoring would have been the right thing to do, and I've been through refactoring efforts that did little to pay back technical debt, even though that was the stated goal. 

* You can tackle it in stages

* You can try to ensure regression, feature parity, add tests

* You can measure progress

You can do the same with rewrites, though I acknowledge it is harder to stage it.

A full rewrite is also a viable strategy. I see it as slightly more risky. Some rewrites are spectacularly successful. Some never make it. Whereas refactoring, by definition keeps exactly the same functionality but improves the code base for those that come after, normally in a time limited way. I can live with either path.

Indeed. I think we have to try to understand what makes either strategy viable. Refactorings is in my opinion the right strategy if

  1. The ground is still changing under your feet
  2. but you have a clear idea of the result, e.g. you are trying to refactor the code base into a well-established framework
  3. You have good testability, so that you can verify that you were in fact refactoring.
  4. There are clear points of attack, i.e. you know what parts of the code can be refactored.

None of these are true for node-solid-server, as far as I can see. Point 3 is especially deadly, it is deadly both for refactoring and rewrites, but it leaves you with no option but to make big rewrites anyway. It seems like we have a pretty good idea now of what solid-server should look like, so point 1 isn't there. I would myself not be advocating a rewrite if 1 was true, so one way to change my mind would be to point out that point 1 is still very true. Point 4 is something that I've challenged you on, we really need to know that. Embarking on a refactoring effort without knowing 4 is meaningless. But I haven't been on the project for very long, and I haven't seen all the code, but @RubenVerborgh has, and he can't see it either, so again, this is a very concrete challenge when discussing this topic that has to be met.

Some specific comments :

Maintenance fixes are still released as v5.0.x, but no more new features.

This sounds a bit like a code freeze to me. As a user, app dev, and occasional maintainer of solid systems, relevant to me is : how long would there be a feature freeze? My estimate would be a rewrite to take c. one year, and I'd be interested in the timelines of those that might like to work on this.

So, we're talking a feature freeze on the server, right? And the server isn't supposed to be evolving a whole lot anyway. The intelligence is supposed to be on the client side. So, the first question is: What kind of feature additions are you expecting from the server in near future? Secondly, would these features be feasible to add with the current server in a reasonable fashion?

We have two examples, delegation, which we used to have in the past seems infeasible to add because it touches so much, and different backend storage, which are also being worked on, but it also seems infeasible. So, what other features would you expect to see that can be done?

I think that we should maintain an open ear to the community, so if anybody contributes new features, we could release a 5.x.y, but they should then be aware that this code may not make it further, and I hope that the community would take greater interest in the rewrite effort.

I'm usually wrong about time estimates, I'll give you that. Multiply by a factor of π... ;-) But the thing is, the spec is there and it is mostly quite clear, and in environments I know, I have done very similar stuff quite quickly. Certainly not a year. I wouldn't count it in months, I think, but it also depends a lot on how much people who have been through the learning process are able to be involved.

As soon as the server has feature parity is achieved

What would be the metric for achieving this. We dont have full test coverage on the server side, for example for command line switches (not even sure how to do that!). And barely any test coverage for apps. How will we ensure apps, and also servers, don't break upgrading from the old server to the new?

We need to create a suite of systems tests first. A test suite that anyone can run to verify their server. We need to do that whether we do a rewrite or a refactoring effort. I think it is the first project we should embark on once 5.0.0 is released.

With that, progress on a rewrite can be measured just as well as a refactoring effort can be measured.

akuckartz commented 6 years ago

We need to create a suite of systems tests first. A test suite that anyone can run to verify their server. We need to do that whether we do a rewrite or a refactoring effort. I think it is the first project we should embark on once 5.0.0 is released.

:+1:

melvincarvalho commented 6 years ago

Just an observation :

Nextcloud on board would require another PHP server that is suited for their purpose

I'd say putting effort into this would be a bigger win for solid. Nextcloud has 25 million users and is growing fast. They have stated an intent to want to work together. Those windows of opportunity do not necessarily stay open indefinitely.

Create a design and implementation and create and implementation in PHP, and if apps work on it, then the proof of concept is successful and we do the same for node solid server. At the same time work on fixing the last few bugs in node solid server (which surround auth) leading to the "it just works", state that @kidehen has polularized!

Several advantages here :

As I say, it's nor my decision. This is a choice for inrupt. I'm happy with any path. But that is the route I would find tempting.

melvincarvalho commented 6 years ago

We would need a proposal for concrete stages from someone. My opinion is that the code is too tangled for that.

What I would suggest is to work only on auth, after 5.0.0, until there is consensus that we have got to "it just works", and at the same time create a documentation of existing interfaces. That would lower the risk of a potential rewrite. This is just food for thought, I dont want to get in the way of consensus!

RubenVerborgh commented 6 years ago

@melvincarvalho Note that you haven't answered the question though. We still need a concrete place to start in order to be able to refactor.

What I would suggest is to work only on auth

But that's the issue: there's no such thing as only working on auth.

An important piece of context for this thread, which we perhaps should have made explicit, is that the current codebase is end of life. So "just work on X" or "just work on Y" is a fallacy, since working on X or Y requires touching large parts of the code, even for small X or Y, and certainly for major ones like auth.

So it's either refactor or rewrite; continuing as-is is not a realistic option.

melvincarvalho commented 6 years ago

the current codebase is end of life

I think it is normal to mark something as end of life, a period of time after, a replacement is available.

RubenVerborgh commented 6 years ago

"End of life" as in unmaintainable.

bergos commented 6 years ago

I would like to use the Solid server or parts of it in some of my projects. With the current architecture and the lack of interfaces, this is very complicated. I doubt it's possible to fix that just with a refactoring. I also expect a rewrite could make progress much faster, as multiple people could work on different modules more conflict free.

melvincarvalho commented 6 years ago

We still need a concrete place to start in order to be able to refactor.

Replying to this for completeness.

I agree it is a challenge to fix bugs, part of this is because solid by design has many moving parts.

I really liked the idea from @bergos

The WebID authentications should be implemented as Passport.js modules as it's the de facto standard for node authentication modules.

So, possibly 6 steps :

This will need to be done probably with either route.

I think that's about all I have to say on this issue. I'll aim to use 5.0.0 when it comes out, and try fix any bugs. Looking forward to following progress on v.next!

RubenVerborgh commented 6 years ago

@melvincarvalho There must be a misunderstanding: the client is neither affected by not involved in any of this, so steps 2/4/6 are not a logical part of a rewrite or refactoring.

elf-pavlik commented 6 years ago

I would like to use the Solid server or parts of it in some of my projects. With the current architecture and the lack of interfaces, this is very complicated. I doubt it's possible to fix that just with a refactoring. I also expect a rewrite could make progress much faster, as multiple people could work on different modules more conflict free.

I recall @msporny expressing interest in some parts of Solid stack, not sure if for https://github.com/digitalbazaar/bedrock or something else. I think contributions from Digital Bazaar team to some common modules would come as a great help.

The WebID authentications should be implemented as Passport.js modules as it's the de facto standard for node authentication modules.

It looks like bedrock has one for HTTP Signatures https://github.com/digitalbazaar/bedrock-passport

msporny commented 6 years ago

I recall @msporny expressing interest in some parts of Solid stack

We expressed interest more at an architectural and "shared goals" level. Much of the thread above talking about an architecture for Solid is effectively describing Bedrock and how we built our "Solid Server"-like system. We'd be happy for Solid to use Bedrock and build on top of it (Bedrock can be used license-free for research purposes). That said, I would expect that some in the Solid project may not like that approach for a variety of different reasons (lack of a "true" open source license being one of them).

Digital Bazaar does create quite a number of open source packages in node.js that the Solid project is welcome to use (node.js libraries for: JSON-LD, Linked Data Proofs, Linked Data Signatures, HTTP Signatures, OCAP-LD, DIDs, Verifiable Credentials, etc.).

In any case, just responding to @elf-pavlik since he tagged me in this issue.

kjetilk commented 6 years ago

We still need a concrete place to start in order to be able to refactor.

Replying to this for completeness.

I agree it is a challenge to fix bugs, part of this is because solid by design has many moving parts.

I really liked the idea from @bergos

The WebID authentications should be implemented as Passport.js modules as it's the de facto standard for node authentication modules.

So, my view is indeed that we should indeed by adopting frameworks for essential parts. As frameworks also tend to come and go (like, myself, I was surprised to see that jQuery was completely out), we need to approach them with a critical mind, but not using them leads us in the much more dangerous pit of NIH, so, I'm all for it.

However, that is hardly suited to inform a "refactor" or "rewrite" decision on its own. The devil is the details, and as I said, adapting code to frameworks is one of the key factors that make refactoring interesting, but it depends on how far the current code is from where it needs to be to fit a given framework. I don't know that, but grepping the source tree for "auth" finds the word in 159 files, and that scares me, most code should be able to safely assume that the agent has been authorized. So, yeah, that's probably bad metric.

I think this is part of the architecture work that needs doing, and yes, I think we need proofs, verifiable identities and that kind of stuff too, so looking into @msporny et als code should also be a part of that.

melvincarvalho commented 6 years ago

@melvincarvalho There must be a misunderstanding: the client is neither affected by not involved in any of this, so steps 2/4/6 are not a logical part of a rewrite or refactoring.

@RubenVerborgh thanks for clarifying, got it! I just added this part in because it was a semver-major upgrade (I've added that tag).

adriangrigore commented 6 years ago

Have you considered Go as the language of choice?

RubenVerborgh commented 6 years ago

@adriangrigore There is an older Go implementation (https://github.com/linkeddata/gold), but the benefit of JavaScript is that we have isomorphic code between the client and the server. For instance, the module performing RDF patches then behaves exactly the same on the client or server.

pjz commented 6 years ago

How about extracting/expanding the test suite to turn it into a validation suite for any Solid server? It's sure to be useful for the soon-to-be-exploding Solid ecosystem. It can start out as 'documenting' the way the current implementation works and then expand to make sure all the protocol's edge and corner cases are well handled.

kjetilk commented 6 years ago

How about extracting/expanding the test suite to turn it into a validation suite for any Solid server?

Yes, I think that is something that we should do as one of the first things we do after the release of v5.0.0.

marcus-sa commented 6 years ago

I'd suggest using https://github.com/nestjs/nest (solves the architecture problem and uses express under the hood)

RubenVerborgh commented 6 years ago

@marcus-sa It seems that Nest is a framework to build Web applications. The Solid server is a personal data store. Wouldn't this be a mismatch?

marcus-sa commented 6 years ago

@RubenVerborgh yeah you're right, just looked through the codebase quickly and saw that you were using express, hence my suggestion. Otherwise you could use this https://github.com/marcus-sa/one which uses the same module architecture principles as Angular and Nest, but where components and controllers are obsolete and not bound to the framework itself and using https://github.com/Inversify/InversifyJS under the hood as IOC making it (one) really extensible. Unfortunately it (one) lacks documentation at the moment.

tmciver commented 6 years ago

I'll throw my hat into this ring. :) I've made only very small contributions to this project but I too have found myself frustrated by the code. I chalked it up to my dislike of and inexperience with Javascript, but it seems others feel the pain too.

Being a proponent of statically typed languages I see two strategies that could be used:

melvincarvalho commented 6 years ago

A couple of suggestions.

For balance, I'd recommend stake holders reading this (rather opinionated) classic. Posted without comment.

https://www.joelonsoftware.com/2000/04/06/things-you-should-never-do-part-i/

@kjetilk I think may be premature to label this as 6.0.0, because we dont know if the 5.0.0 API will change before "this" lands. Suggest, keeping it as semver major, and giving it a codename or calling it v.next.

melvincarvalho commented 6 years ago

Less controversial I think is that if we are going to follow the sever spec (which we dont have to) after 1.0 the API should be fully documented.

Then any changes to that API should be the starting point of a semver major upgrade. I'm unsure we have done that, but it would seem to be a good starting point?

RubenVerborgh commented 6 years ago

For balance, I'd recommend stake holders reading this (rather opinionated) classic. Posted without comment.

Let me just pull out a quote for reflection then :wink:

It’s important to remember that when you start from scratch there is absolutely no reason to believe that you are going to do a better job than you did the first time.

I think may be premature to label this as 6.0.0, because we dont know if the 5.0.0 API will change before "this" lands.

You're right from an API perspective, but a rewritten or refactored version should probably still have a semver major change for safety reasons. That said, happy with v.next.

Less controversial I think is that if we are going to follow the sever spec (which we dont have to) after 1.0 the API should be fully documented.

Oops, I did not follow that for many of my projects 😮 We should probably aim for the spec being the documentation of the HTTP API. (But there's also the JS API then.)

kjetilk commented 6 years ago

For balance, I'd recommend stake holders reading this (rather opinionated) classic. Posted without comment.

Let me just pull out a quote for reflection then wink

It’s important to remember that when you start from scratch there is absolutely no reason to believe that you are going to do a better job than you did the first time.

Ah, but that is the essence of what I've been saying all along. They were coding in an unknown, changing world, we are coding in a known world. That's a huge difference. And it is the difference that makes that statement wrong. Netscape folks were coding to a world that was changing at a tremendous pace.

I don't know how long it'll take to rewrite it, but what I'm pretty sure is that it will take several years to get the current code into shape, and I'm pretty sure we would have changed every single line in the process.

So, it is an unfortunate fact that we do not have those who learned those lessons in the group anymore. That's a problem. I acknowledge that.

Consider this analogy: What we have now is a pyramid. It has been built with massif effort, with one architectural element: The Rock. Rocks are stacked upon other rocks to form the shape of a Pyramid. What we want is something like an Eiffel tower. Eiffel actually architected the tower based on a few thousand more years of knowledge in engineering, based on thousands of years of knowledge in physics. With that, he knew that he didn't need much material, and he could mix many architectural elements so that the tower would stand, in spite of being a much less massive construction. What might want to think that we want to have something that looks exactly like the great Pyramid of Giza, but we don't, we know that there are several things that we cannot efficiently build on the current architecture. We need something that has a top and four corners, though, that's given by the Solid spec.

Rewriting the server amounts to trying to remove the rocks that aren't necessary, based on thousands of years of knowledge, until it looks like an Eiffel tower, while making sure that it doesn't fall over in the process. This is how I understand it, and I believe that the conjecture that setting out on this path is going to be less expensive than just building the Eiffel tower is a pretty bold conjecture that needs substantial collaboration to be believable.

I think may be premature to label this as 6.0.0, because we dont know if the 5.0.0 API will change before "this" lands.

Sure. Lets not call it by a version number. v.next works for me.

melvincarvalho commented 6 years ago

I don't know how long it'll take to rewrite it, but what I'm pretty sure is that it will take several years to get the current code into shape

@kjetilk this comes across as an appeal to authority, concrete details of what we can fix, I find easier to digest.

Im looking forward to a concrete design proposal, which I hope would be an input to v.next. Typescript interfaces are a good start. Documenting the current API as per the semver spec also will help.

With my user hat on, I see the risk that the upgrade path from 5+ to v.next to have breaking changes. One thing that would be persuasive in the design to me would be a module system that could extend the functionality of node solid server -- Im not sure if that's feasible, though. Food for thought!

melvincarvalho commented 6 years ago

That said, happy with v.next.

@RubenVerborgh I think there's going to be a need for some things after v5 comes out.

Off the top of my head, having been to several years of meetings on this :

We've wanted the ability for the server to save who has written a file, if they are authenticated.

We've also wanted atomic updates to more than one file at once.

Just examples, there could be more.

RubenVerborgh commented 6 years ago

@melvincarvalho What we are trying to argue here is that such seemingly simple features are extremely complex on the current codebase, and that implementing n such features on the old server will effectively cost more work (for a less qualitative result) than rewriting the server and implementing those features there.

Case in point: do check the code that was needed to implement account deletion, and the few quality guarantees we can give on that code.

Providing concrete details of fixes is something I'm asking from anyone who suggests a refactoring. I have argued above that I cannot find such fixes, hence my preference for a rewrite.

A new version of the server might have some breakage, but many more things are broken with the current server that are hard to fix.

melvincarvalho commented 6 years ago

@RubenVerborgh I hear you loud and clear!

My point is that there is a mix of arguments in this thread. Some appeal to authority, some anecdotal evidence, some burden of proof shifting, some proof by analogy, and some technical details.

What I'm saying is that the Eiffel Tower / Pyramid of Gaza metahpor, while colorful is less persuasive than the complexity of deleting an account, which is a great input.

Taking this case study. We can ask why was it so hard. This could well be the architecture or it could also point to the design. Do we have a link to the design?

Deleting an account on a server can literally be 1 line of code.

mv data/account deleted/account

Which has the advantage of being able to undelete, say if your password was stolen or someone had access to your browser while you were not at your device.

Lots of great points made. Im just saying that technical details are helpful for review and analysis.

RubenVerborgh commented 6 years ago

One line of code doesn't work; there's still the account db and associated management.

pjz commented 6 years ago

How about first working on a validation suite for Solid servers in general? Then if one group wants to write a server from scratch, they have a target to aim at, and if another wants to whip this codebase into shape, they can rest assured they're not breaking anything in the process.

RubenVerborgh commented 6 years ago

Such an implementation-independent test suite is part of the plan indeed, can also be used for servers in different languages.

pjz commented 6 years ago

Right, so I guess my suggestion is: table whether to fix or rewrite this codebase (the overall question here) until there's a good validation test suite to allow either to be done in a safe and sane fashion.

RubenVerborgh commented 6 years ago

In theory, your right; in practice, we have finite resources and a high speed at which we need to move.

elf-pavlik commented 6 years ago

I think in the end who does the job calls the shots and contributors insight gives a good notion of that part of the equation.

kjetilk commented 6 years ago

@melvincarvalho Yeah, I appreciate your call for details, but we need to have 5.0.0 out before we can devote more time to v.next.