π Also this is a draft for the release notes. I'll be updating it in the coming days.
π This is an alpha release! Most of the extensions will be broken at this point.
π Who this release is for:
π Since this release is an alpha release if you want to test it you must specify the version when using pip:
$ pip install "thumbor==7.0.0a5"
$ thumbor-doctor
Keep on reading for the changes you need to be aware of. If you experience any problems, please run thumbor-doctor --nocolor and create an issue with your problem and the results of running thumbor-doctor.
π This release notes will be slightly different from others as I feel we need to have more of a conversation on what happened. I'll try to detail the changes below, but first I'll explain them.
π We set out to update thumbor to work with python3. During the work required to do that, it became clear that we were going to break most extensions with this release.
β‘οΈ At this point we made a decision to not only update thumbor to python3, but completely modernize it.
Some of the 7.0.0 features:
β‘οΈ While updating the codebase to support new tornado and python 3 we also decided to get rid of the callback hell that tormended the committers for the last 10 years or so. The new codebase uses proper async/await idioms for all the asynchronous code.
As the last part of the intro, we added a new concept to customizing thumbor: handler lists. It has been a request for a long time to allow thumbor extensions to add new handlers to thumbor. Well, now you can!
Lets get to the details!
π First let's see what breaks (apart from not supporting python 2, that is).
Previously storages were implemented like this (this is No Storage):
class Storage(BaseStorage): def put(self, path, bytes): return path def put\_crypto(self, path): return path def put\_detector\_data(self, path, data): return path @return\_futuredef get\_crypto(self, path, callback): callback(None) @return\_futuredef get\_detector\_data(self, path, callback): callback(None) @return\_futuredef get(self, path, callback): callback(None) @return\_futuredef exists(self, path, callback): callback(False) def remove(self, path): pass
π With release 7.0.0 we modernize these functions to be async. The same storage in the new release:
class Storage(BaseStorage): async def put(self, path, file\_bytes): return path async def put\_crypto(self, path): return path async def put\_detector\_data(self, path, data): return path async def get\_crypto(self, path): return Noneasync def get\_detector\_data(self, path): return Noneasync def get(self, path): return Noneasync def exists(self, path): return Falseasync def remove(self, path): pass
β‘οΈ Much simpler, right? No funky callback business. The downside is that all storages out there need to be updated. It should be simply a matter of "asyncifying" them.
π The same applies to loaders. Let's see what a loader looked like in 6.7.2:
@return\_futuredef load(context, path, callback): # does a lot of stuff and :( callback(loaded\_image)
Now in 7.0.0 it is a simple async function:
async def load(context, path): # does a lot of stuff with no callbacks whatsoeverreturn loader\_result
It's much simpler to understand the new loaders (and to create new ones), but the same issue as above: previous loaders won't work with thumbor 7.0.0+ (until asyncified).
β‘οΈ Important note: going forward, loaders should return LoaderResult object. While returning plain image bytes still works, it's encouraged to update loaders to return object.
You get the gist, right? No Storage Result Storage in 6.7.2:
class Storage(BaseStorage): # THIS METHOD IS NOT EVEN ASYNC :(def put(self, bytes): return ''@return\_futuredef get(self, callback): callback(None)
Now in 7.0.0+:
class Storage(BaseStorage): async def put(self, image\_bytes): return ""async def get(self): return None
Previous result storages won't work with thumbor 7.0.0+ (until asyncified).
Same ol', same ol'. Let's check format filter in 6.7.2.
class Filter(BaseFilter): @filter\_method(BaseFilter.String) def format(self, format): if format.lower() not in ALLOWED\_FORMATS: logger.debug('Format not allowed: %s' % format.lower()) self.context.request.format = Noneelse: logger.debug('Format specified: %s' % format.lower()) self.context.request.format = format.lower()
Now the same filter in 7.0.0:
class Filter(BaseFilter): @filter\_method(BaseFilter.String) async def format(self, file\_format): if file\_format.lower() not in ALLOWED\_FORMATS: logger.debug("Format not allowed: %s", file\_format.lower()) self.context.request.format = Noneelse: logger.debug("Format specified: %s", file\_format.lower()) self.context.request.format = file\_format.lower()
Hardly noticeable, right? Except now you get to run async code in your filters without arcane magic or callbacks. As with all the others, previous filters won't work with thumbor 7.0.0+ (until asyncified).
These were also modernized. Let's take a look at our face detector in 6.7.2:
class Detector(CascadeLoaderDetector): # details removed for claritydef detect(self, callback): features = self.get\_features() if features: for (left, top, width, height), neighbors in features: top = self.\_\_add\_hair\_offset(top, height) self.context.request.focal\_points.append( FocalPoint.from\_square(left, top, width, height, origin="Face Detection") ) callback() else: self.next(callback)
Now the same detector in 7.0.0+:
class Detector(CascadeLoaderDetector): # details removed for clarityasync def detect(self): features = self.get\_features() if features: for (left, top, width, height), \_ in features: top = self.\_\_add\_hair\_offset(top, height) self.context.request.focal\_points.append( FocalPoint.from\_square( left, top, width, height, origin="Face Detection" ) ) returnawait self.next()
β‘οΈ No more callbacks and now detector pipeline works by awaiting the next detector or just a plain early return to stop the pipe. As with the other updates, previous detectors will not work with thumbor 7.0.0 (until asyncified).
β
This one is for you, an extension author! Thumbor now includes a thumbor.testing module that ships with it and allows extensions to create tests that get thumbor up and running easier. An example test from our code:
from preggy import expectfrom tornado.testing import gen\_testfrom thumbor.testing import TestCasefrom thumbor.storages.no\_storage import Storage as NoStorageclass NoStorageTestCase(TestCase): def get\_image\_url(self, image): return "s.glbimg.com/some/{0}".format(image) @gen\_testasync def test\_store\_image\_should\_be\_null(self): iurl = self.get\_image\_url("source.jpg") storage = NoStorage(None) stored = await storage.get(iurl) expect(stored).to\_be\_null() # many more tests!
β Notice how the test can now test only what it needs to. We're using py.test now and that allows async test methods.
π The many fundamental changes in thumbor prompted a major review of the docs and improvement of many areas in it.
Not all is breaking changes, though. Now you get to extend thumbor with new handlers! And it is as simple as creating a module with:
from typing import Any, cast from thumbor.handler\_lists import HandlerList from my.handlers.index import IndexHandler def get\_handlers(context: Any) -\> HandlerList: something\_enabled = cast(bool, self.context.config.SOMETHING\_ENABLED) if not something\_enabled: return [] return [(r"/my-url/?", IndexHandler, {"context": self.context}),]
Then including it in thumbor.conf:
from thumbor.handler\_lists import BUILTIN\_HANDLERS# Two things worth noticing here:# 1) The handler list order indicates precedence, so whatever matches first will be executed;# 2) Please do not forget thumbor's built-ins or you'll kill thumbor functionality.HANDLER\_LISTS = BUILTIN\_HANDLERS + ["my.handler\_list',]
π This release would not be possible without the work of thumbor's commiters. I'd like to call out the work of @kkopachev that has enabled me to move forward with this release.
π Again thanks @kkopachev for all the code reviews and thanks the whole of thumbor community for catching errors when I hadn't even written the release notes! That's nothing short of amazing.
π Now onto the not comprehensive list of changes in this release!
thumbor-doctor command to help diagnose issues with installs.π Diff to previous release
π Pypi release
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