Affero not harmful [LWN.net]

Affero not harmful

Posted Feb 8, 2017 5:55 UTC (Wed) by ncm (guest, #165)
In reply to: RethinkDB source relicensed, donated to the Linux Foundation by Cyberax
Parent article: RethinkDB source relicensed, donated to the Linux Foundation

MongoDB is licenced under Affero, and seems to be used a fair bit. At least, its monthly download rate is in the mid 10^5s, and it just got reliably linearizable durable distributed writes, which depends on quite a lot of sustained developer attention. It seems like some other reason is needed to explain why RethinkDB didn't end up driving a growing business.

It might be a better question why a project takes off than why it falters, because faltering is the usual outcome. But not studying why projects falter might ensure that yours will. Licenses don't seem to be among the main reasons either way.

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Affero not harmful

Posted Feb 8, 2017 21:40 UTC (Wed) by Cyberax (✭ supporter ✭, #52523) [Link] (8 responses)

MongoDB _is_ corporate shareware. Pretty much all large companies that actually use it have a commercial license for it.

Besides, Mongo quite explicitly restricts the AGPL range: "To say this another way: if you modify the core database source code, the goal is that you have to contribute those modifications back to the community". I was assured by our lawyer that this interpretation is not necessarily the intent of the AGPL license and can't be applied to other projects.

I actually don't mind a good LGPL-like cloud license (A-LGPL?) that has a strictly limited scope of what's considered a derived work. And better legal implementation.

Affero not harmful

Posted Feb 8, 2017 23:47 UTC (Wed) by Wol (subscriber, #4433) [Link]

Maybe like the MPL?

"If you modify MPL code you must release your changes. If you keep your code as separate modules then they are not covered by the MPL." Okay, that's my paraphrase but that's pretty much how the MPL works.

Cheers,
Wol

Affero not harmful

Posted Feb 9, 2017 1:01 UTC (Thu) by ncm (guest, #165) [Link] (6 responses)

Cy, when did you start peddling falsehoods on LWN?

Large companies who buy support get management tools and help. The database itself really is free, and Free, in every sense, but it's the nature of databases used for Important Things to need competent management, which never comes cheap.

Everything the management tools do could be done by hand, or with custom scripts, but it doesn't take long for a large company to discover that that is the more expensive course.

Resolutely getting back on topic, the Affero license and a really-truly free database substrate has demonstratedly done MongoDB no harm. Look elsewhere for explanations.

Affero not harmful

Posted Feb 9, 2017 5:50 UTC (Thu) by Cyberax (✭ supporter ✭, #52523) [Link] (5 responses)

Ok, let me quickly recap what several lawyers told me.

First, enterprise MongoDB has a special commercial license for the DATABASE itself. Not just for additional tools. Consequently, contributing to MongoDB requires copyright assignment to Mongo ( https://www.mongodb.com/legal/contributor-agreement ).

Next, let's talk about AGPL. It poorly defines what "derived works" actually are, just as regular GPL licenses. However, there are some guidelines (including from the FSF itself). In particular, if a program uses internal structures of another system, is tightly bound to it and works in the same address space then it's pretty certain that it's a derived work and GPL applies.

In case of MongoDB most real databases will have views, map/reduce queries and other code that fit these conditions perfectly. So their code can be considered a derived work of Mongo and will have to be disclosed as per AGPL if its output is used (for example) to render HTML pages.

This is clearly insane. So MongoDB has a public interpretation of the license that excludes normal database users from AGPL's reach. But they are free to rescind this interpretation at any moment - it won't be retroactive but any code running within future MongoDB versions won't be protected from AGPL.

And before people start telling that "but Mongo queries are just like C code being processed by GCC" - they are not. They are more comparable with GCC plugins and FSF's opinion is that they must be GPL.

Affero not harmful

Posted Feb 10, 2017 15:40 UTC (Fri) by Wol (subscriber, #4433) [Link] (1 responses)

> This is clearly insane. So MongoDB has a public interpretation of the license that excludes normal database users from AGPL's reach. But they are free to rescind this interpretation at any moment - it won't be retroactive but any code running within future MongoDB versions won't be protected from AGPL.

Are they free? (I don't have a clue.) Or does the copyright assignment have clauses (like the FSF do) preventing the closure of the code?

The FSF can't close any code they've been given the copyright to, because part of the copyright transfer forbids it.

Cheers,
Wol

Affero not harmful

Posted Feb 10, 2017 18:15 UTC (Fri) by Cyberax (✭ supporter ✭, #52523) [Link]

> Are they free? (I don't have a clue.) Or does the copyright assignment have clauses (like the FSF do) preventing the closure of the code?
MongoDB's CLA gives Mongo unconditional rights to do anything they want with contributions.

Affero not harmful

Posted Feb 13, 2017 7:56 UTC (Mon) by ncm (guest, #165) [Link] (2 responses)

Getting code into Mongo's github would take a copyright assignment, as with FSF. (And you would need to persuade them to pull it, likely not an easy task.) But, just as with FSF, you are free to fork the source and distribute it with your own code. People do, e.g. RockDB. So, Free. If they change the license, you still have your code and your fork.

Enterprise customers do get a different license that gives them access to extra stuff they want. But none of that is necessary to use or to change and redistribute the code. As you note, Mongo specifically disclaim ownership of your "views" etc. So, what is not Free? That you can't take it proprietary, as you can with PosgreSQL? How are they different, in that way, from Red Hat?

Affero not harmful

Posted Feb 13, 2017 8:28 UTC (Mon) by Cyberax (✭ supporter ✭, #52523) [Link] (1 responses)

No, it's not. Any code that is dual-licensed under a proprietary license is not free. It's merely shareware.

And I can't even find what RockDB is...

Fun fact, Mongo's license disclaimer actually can NOT be legally applied by their downstream forks.

Affero not harmful

Posted Feb 14, 2017 10:57 UTC (Tue) by micka (subscriber, #38720) [Link]

If it's RocksDB, then I think it's a fork of LevelDB.
(I just recently had a dive into these kind of databases)
Those are key-values DB AFAIK (while mongodb is a document database).