I would recommend option III.
IMHO, hierarchy based endpoints are for CURD operations on a single
entity. The flat endpoint, like /taskinstance, is for read-only
multi-facet search queries.
For example:
* to create a resource Foo: "POST /api/parent/{parent_id}/foo"
* to update a resource Foo: "PUT /api/parent/{parent_id}/foo/{foo_id}"
* to get a single Foo entity: "GET /api/parent/{parent_id}/foo/{foo_id}"
* to search for multiple Foo entities using multiple filters: "GET
/api/foo?parent_id=id1,id2,id3&owner=user1"
On Mon, May 11, 2020 at 5:08 AM Kamil Breguła <kamil.breg...@polidea.com> wrote:
>
> Hello,
>
> I apologize for my very negative behavior. I misunderstood the rules.
> I updated the specification based on the discussion. I hope that now I
> have not missed any suggestions that I had to make. I tried to make
> every change in a separate commit, so you can review the changes one
> by one.
>
> Here is new PR: https://github.com/apache/airflow/pull/8721
>
> Short summary:
> * Changed type for DAGID, DAGRunID, TaskID. Now we use string instead
> of an integer.
> * EventLog collection is read-only
> * Used ExcutionDate in DagRuns endpoints
> * Used custom action to control task instances - Removed PATCH
> /dags/{dag_id}/taskInstances/{task_id}/{execution_date} endpoint and
> added PATCH /dags/{dag_id}/clearTaskInstanaces.
> * Added endpoint - POST /dagRuns "Trigger a DAG Run"
> * Added filter parameters to GET /dags/{dag_id}/taskInstances.
> * Added filter parameters to GET /dags/{dag_id}/dagRuns
> * Removed DELETE /taskInstances endpoint
> * The connection ID is a unique key that identifies the connection
> * Moved TaskInstances resource under DagRuns resource
> * Fixed many typos
>
> There is one more topic for discussion - reading resources across
> multiple collections.
> In other words - how do I retrieve task instances for multiple DAGs?
> We have several solutions.
> I) Currently, the endpoint that receives a list of task instances is
> available at /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances:
> This endpoint support reading resources across multiple DAGs by
> specifying a "-" as a dag_id or an execution_date.
> This is based on Google recommendations - AIP159 [1]. I relied on
> these recommendations because it is the most comprehensive study on
> API design principles. Ash Berlin-Taylor rightly pointed out that this
> would be a backward-incompatible change.
> II) We can use a different character that will have the same role -
> '*'. This character cannot be in Dag/Task ID, so it's safe.
> III) Ash proposed to add a separate endpoint that will not include the
> DAG ID in the address - /taskInstances
>
> If we want to choose one solution then I think it's worth looking at
> what the endpoints for DAGs look like.
> /dags
> /dags/{dag_id}
> /dags/{dag_id}/clearTaskInstanaces
> /dags/{dag_id}/dagRuns
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances/{task_id}/
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances/{task_id}/links
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances/{task_id}/logs/{task_try_number}
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances/{task_id}/xcomEntries
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances/{task_id}/xcomEntries/{key}
> /dags/{dag_id}/dagRuns/{execution_date}
> /dags/{dag_id}/structure
> /dags/{dag_id}/tasks
> /dags/{dag_id}/tasks/{task_id}
> In my opinion, here is a clear hierarchy of resources that will
> facilitate the use of API. The third solution causes that this
> hierarchy is disturbed and the endpoints that are used to receive the
> list of elements will be at the highest level.
> We will have the following endpoints:
> /dags
> /dags/{dag_id}
> /dags/{dag_id}/clearTaskInstanaces
> /dagRuns
> /dags/{dag_id}/dagRuns
> /taskInstances
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances/{task_id}/
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances/{task_id}/links
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances/{task_id}/logs/{task_try_number}
> /xcomEntries
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances/{task_id}/xcomEntries
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances/{task_id}/xcomEntries/{key}
> /dags/{dag_id}/dagRuns/{execution_date}
> /dags/{dag_id}/structure
> /dags/{dag_id}/tasks
> /dags/{dag_id}/tasks/{task_id}
>
> 4) Some endpoints will have similar behavior, so we can delete them.
> Then we will have the following list of endpoints.
> /dags
> /dags/{dag_id}
> /dags/{dag_id}/clearTaskInstanaces
> /dagRuns
> /taskInstances
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances/{task_id}/
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances/{task_id}/links
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances/{task_id}/logs/{task_try_number}
> /xcomEntries
> /dags/{dag_id}/dagRuns/{execiton_date}/taskInstances/{task_id}/xcomEntries/{key}
> /dags/{dag_id}/dagRuns/{execution_date}
> /dags/{dag_id}/structure
> /dags/{dag_id}/tasks
> /dags/{dag_id}/tasks/{task_id}
>
> Which solution do you like the most? I, II, III, or IV?
>
> Best regards,
> Kamil Breguła
>
> [1] https://aip.dev/159
>
> On Wed, Apr 15, 2020 at 8:32 PM Daniel (Daniel Lamblin ) [Data
> Infrastructure] <lamb...@coupang.com> wrote:
> >
> > I'm glad the general mood is that connection_id should be unique.
> > FWIW when I had multiple connections in v1.8.2 with mysql I didn't seem to
> > be getting any randomized loadbalancing anyway. Then again, maybe random
> > was just 100 selections of 1 over 2.
> > There are many other ways to load balance connections, each specific to the
> > service type, so I don't see it Airflow's place to provide a semi-generic
> > option to do it.
> >
> > +1 for connection ID being unique.
> >
> > Pardon outlook for changing links to the ConnectionID, DagID and PoolID
> > being integers in a version of the API.
> > Are we past that decision already; I'd expect to use string names.
> >
> > I'd also asked about DAG run ID, task ID, and finally whether there'd be an
> > endpoint with which to clear tasks, because crud operations don't model the
> > interplay of task instance, jobs, and dag run state involved.
> > -Daniel
> >
> > On 4/14/20, 8:49 AM, "Xinbin Huang" <bin.huan...@gmail.com> wrote:
> >
> > [Warning]: This email originated from an external source. Do not open
> > links or attachments unless you know the content is safe.
> > [경고]: 본 이메일은 회사 외부에서 유입되었습니다. 내용이 안전한지 확인하기 전까지는 링크나 첨부파일을 열지 마십시오.
> >
> >
> > +1 on making connection IDs unique. It's confusing to have Airflow
> > handled
> > load balancing here.
> >
> > On Tue, Apr 14, 2020, 4:59 AM Kaxil Naik <kaxiln...@gmail.com> wrote:
> >
> > > +1 to make connection ids unique
> > >
> > > On Tue, Apr 14, 2020 at 11:59 AM Jarek Potiuk
> > <jarek.pot...@polidea.com>
> > > wrote:
> > >
> > > > I am also supporting converting the connection to be unique.
> > > >
> > > > I've worked with similar approach long time ago (10s of years) and
> > it was
> > > > fine then where we have not yet figured out how to scale
> > client/server
> > > > architecture and we did not have all the nice infrastructure like
> > > > load/balancing, cloud services etc. I believe in most of the current
> > > > services/systems load-balancing should be handled by the service
> > itself
> > > or
> > > > some kind of proxy between - not by the client side - in production
> > > > environments.
> > > >
> > > > It's far more robust and might provide much better control (you can
> > > control
> > > > multiple independent client's connection and do not rely on random
> > > > distribution of connections). There are scenarios that would not
> > work
> > > well
> > > > in this case - for example physical proximity of the workers,
> > current
> > > load
> > > > on different services etc. etc. It is very limiting to rely on this
> > > > feature.
> > > >
> > > > On Tue, Apr 14, 2020 at 11:36 AM Kamil Breguła <
> > > kamil.breg...@polidea.com>
> > > > wrote:
> > > >
> > > > > Hello,
> > > > >
> > > > > This can cause big problems with idempotence. According to
> > RFC-7231,
> > > > > the DELETE method should be idempotent.
> > > > >
> > > > > For example:
> > > > > If you want to delete items with index from 1 to 4, you should
> > set the
> > > > > following request
> > > > > DELETE /connections/hdfs_default/4
> > > > > DELETE /connections/hdfs_default/3
> > > > > DELETE /connections/hdfs_default/2
> > > > > DELETE /connections/hdfs_default/1
> > > > >
> > > > > However, if the user sends these requests in a different order,
> > they
> > > > > will only delete the first and third items.
> > > > > DELETE /connections/hdfs_default/1
> > > > > DELETE /connections/hdfs_default/2
> > > > > DELETE /connections/hdfs_default/3
> > > > > DELETE /connections/hdfs_default/4
> > > > >
> > > > > If you use asynchronous HTTP clients (a popular in Node), the
> > order of
> > > > > requests will not be kept. It will also be a big problem with
> > > > > simultaneous modifications.
> > > > >
> > > > > I am also in favor of abandoning support for many connections.
> > This
> > > > > can be solved on a different layer.
> > > > >
> > > > > Best regards,
> > > > > Kamil
> > > > >
> > > > >
> > > > > On Thu, Apr 9, 2020 at 6:47 PM Ash Berlin-Taylor <a...@apache.org>
> > > wrote:
> > > > > >
> > > > > > They are, but we _can_ make a choice to remove that feature --
> > it is
> > > > not
> > > > > > widely used and is confusing to many when they stumble on it.
> > > > > >
> > > > > > It's not something we should do lightly, but it is a
> > possibility.
> > > > > >
> > > > > > I think I'm probably leaning towards the "ordinal" concept:
> > > > > >
> > > > > > /connections/hdfs_default -> list of connections with that ID
> > > > > > /connections/hdfs_default/0 first connection of that type
> > > > > >
> > > > > > Something like that.
> > > > > >
> > > > > > On Apr 9 2020, at 2:31 pm, Shaw, Damian P.
> > > > > > <damian.sha...@credit-suisse.com> wrote:
> > > > > >
> > > > > > > FYI if you look back at the thread "Re: [2.0 spring cleaning]
> > > Require
> > > > > > > unique conn_id" on 2019-04-14 you can see a message from
> > Kevin Yang
> > > > > > > stating that this random choice of connections is a "feature"
> > used
> > > to
> > > > > > > load balance connections in AirBnB. So users are relying on
> > this
> > > > > behavior.
> > > > > > >
> > > > > > >
> > > > > > > -----Original Message-----
> > > > > > > From: Daniel (Daniel Lamblin ) [Data Infrastructure]
> > > > > > > <lamb...@coupang.com>
> > > > > > > Sent: Wednesday, April 8, 2020 20:01
> > > > > > > To: dev@airflow.apache.org
> > > > > > > Subject: Re: API spec questions
> > > > > > >
> > > > > > > Having been bit by accidentally having two connections by the
> > same
> > > > > > > name or conn_id, I'd prefer if were made unique. In my
> > experience
> > > > > > > there's little utility in having multiple connections by the
> > same
> > > > > > > name. Tasks that use a connection do to fairly randomly
> > choose one,
> > > > > > > rather they seem pretty consistent in using the one created
> > > earliest,
> > > > > > > which often has the lower id integer.
> > > > > > >
> > > > > > > Circling back to how this is used by the API, from a user
> > > > perspective,
> > > > > > > the following in path integer fields were ones I'd have
> > expected to
> > > > be
> > > > > > > strings instead:
> > > > > > > ConnectionID
> > > > >
> > > >
> > >
> > https://kor01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fapache%2Fairflow%2Fblob%2F11f1e0cad996d5596e3e4fb440eb4ec52c024f70%2Fopenapi.yaml%23L1845&data=02%7C01%7Clamblin%40coupang.com%7Cd8716c2432c54849f3d708d7e08b68f2%7Ce3098f96361b47c6a9f4ab7bafcaffe9%7C0%7C0%7C637224761681223746&sdata=ur3AAggOlQ7BskKBxQxRq0i%2FS36Ol72c7H7ddwXo5C4%3D&reserved=0
> > > > > > > DAGID
> > > > >
> > > >
> > >
> > https://kor01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fapache%2Fairflow%2Fblob%2F11f1e0cad996d5596e3e4fb440eb4ec52c024f70%2Fopenapi.yaml%23L1853&data=02%7C01%7Clamblin%40coupang.com%7Cd8716c2432c54849f3d708d7e08b68f2%7Ce3098f96361b47c6a9f4ab7bafcaffe9%7C0%7C0%7C637224761681223746&sdata=vyhFiV6Fd3pnVvlAoxnscSvvcy2NX%2BMASGmuHKu%2Fy84%3D&reserved=0
> > > > > > > PoolID
> > > > >
> > > >
> > >
> > https://kor01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fapache%2Fairflow%2Fblob%2F11f1e0cad996d5596e3e4fb440eb4ec52c024f70%2Fopenapi.yaml%23L1901&data=02%7C01%7Clamblin%40coupang.com%7Cd8716c2432c54849f3d708d7e08b68f2%7Ce3098f96361b47c6a9f4ab7bafcaffe9%7C0%7C0%7C637224761681223746&sdata=4Fog92AZju0%2BN44FoBdU4fj2DwhgCbUfKYUbdjeWpgo%3D&reserved=0
> > > > > > >
> > > > > > > Though it’s a url-encoding hassle, I also expected that
> > DAGRunID
> > > > would
> > > > > > > be more like the Run ID E.G.
> > > > > > > "scheduled__2020-04-08T23:10:00+00:00",
> > > > > > > "manual__2020-04-08T23:00:56+00:00",
> > > > > > > "manual__2020-04-08T16:24:56.692868+00:00" ,
> > > > > > > "backfill_2020-04-08T22:05:00+00:00" etc
> > > > > > >
> > > > > > > Then TaskID is confusing to me; AFAIK the PK to task
> > instances are
> > > > > > > task_id, dag_id, and execution_date and the api call appears
> > to
> > > align
> > > > > > > with that having the pattern:
> > > > > > > /dags/{dag_id}/taskInstances/{task_id}/{execution_date}:
> > > > > > > But if task_id is a numbered id, then… execution_date isn't
> > even
> > > > > > > needed… I'm thinking it should have been a string.
> > > > > > >
> > > > > > > An aside to this, I've always wondered what happens if an
> > > externally
> > > > > > > triggered DAG Run has the same execution date as a
> > pre-existing
> > > > > > > scheduled DAG Run. They'd have different run_ids, EG
> > > > > > > "scheduled__2020-04-08T23:10:00+00:00" vs
> > > > > > > "manual__2020-04-08T23:10:00+00:00" but then task instances
> > for
> > > those
> > > > > > > runs might not be unique.
> > > > > > >
> > > > > > > Lastly, the UI and CLI operation of clearing tasks seems
> > analogous
> > > to
> > > > > > > the delete task instance API end point. But probably it's
> > not, and
> > > > > > > this could become confusing to users.
> > > > > > > There should be a non-db-model api call for clearing tasks
> > like you
> > > > > > > can from the UI and the CLI. If I read it right, clearing
> > does the
> > > > > > > following: it sets the state of the task instance to None
> > unless
> > > the
> > > > > > > state was Running then instead it sets it and related job ids
> > to
> > > > > > > Shutdown. It deletes reschedules of the TI and it sets the
> > dag runs
> > > > > > > for those task instances back to Running.
> > > > > > > This would be a lot to do for a user using PATCH calls to
> > change
> > > Task
> > > > > > > Instances and Dag Runs together (and there's no API for Jobs).
> > > > > > >
> > > > > > > -Daniel L.
> > > > > > > P.S. as far as renaming all parameters on operators and hooks
> > with
> > > > > > > *_conn_id, I do not want to see that breaking change happen.
> > But IF
> > > > it
> > > > > > > HAS TO, I'm still of the opinion that the default_args use for
> > > > > > > X_conn_id is not preferable to having all operators take
> > simpler
> > > > > > > source_conn_id and optional target_conn_id parameter names
> > that are
> > > > > > > consistent across all operators.
> > > > > > >
> > > > > > > On 4/8/20, 9:47 AM, "Ash Berlin-Taylor" <a...@apache.org>
> > wrote:
> > > > > > >
> > > > > > > [Warning]: This email originated from an external source.
> > Do not
> > > > > > > open links or attachments unless you know the content is safe.
> > > > > > > [경고]: 본 이메일은 회사 외부에서 유입되었습니다. 내용이 안전한지 확인하기 전까지는 링크나 첨부파일을
> > 열지
> > > > 마십시오.
> > > > > > >
> > > > > > >
> > > > > > > To expand on the "so I think we need to do one of":
> > > > > > >
> > > > > > >
> > > > > > > - we need to update the name of "conn_id" somehow. I can't
> > think
> > > > of
> > > > > a
> > > > > > > better option, and given all the operators have
> > "x_conn_id" I
> > > > don't
> > > > > > > think that change should be made lightly.
> > > > > > >
> > > > > > > - make conn_id unique (this "poor" HA has been a source of
> > > > > > > confusion in
> > > > > > > the past) and the ID we use in the API
> > > > > > >
> > > > > > > Or a third option:
> > > > > > >
> > > > > > > - Have the API take conn_id and either return all conns
> > for that
> > > > > > > conn_id, or conn_id plus an ordinal (?idx=0 type thing) to
> > > return
> > > > a
> > > > > > > single value.
> > > > > > >
> > > > > > > On Apr 8 2020, at 5:42 pm, Ash Berlin-Taylor
> > <a...@apache.org>
> > > > > wrote:
> > > > > > >
> > > > > > > > Hi everyone,
> > > > > > > >
> > > > > > > > So as I mentioned in the AIP voting thread, I think we
> > need to
> > > > > give
> > > > > > > > some more thought to how we are exposing connection ids
> > in the
> > > > > API.
> > > > > > > >
> > > > > > > > Right now as proposed (and merged without approval, not
> > cool.
> > > > The
> > > > > AIP
> > > > > > > > we voted on did not contain a PR against
> > apache/airflow.) it
> > > has
> > > > > an
> > > > > > > > end point of `/connections/{connection_id} `
> > > > > > > >
> > > > > > > > My issue here is as I said in the previous thread: that
> > is
> > > going
> > > > > > > to be
> > > > > > > > mightly confusing to our users because there is a
> > "conn_id"
> > > > > concept
> > > > > > > > that is exposed, so people are going to try putting
> > > > "aws_default"
> > > > > etc
> > > > > > > > in there. I don't care what the API spec says, I care
> > what our
> > > > > users
> > > > > > > > expect, and having a connection_id/id and a conn_id
> > fields is
> > > > > > > just confusing
> > > > > > > >
> > > > > > > > So I think we need to do one of:
> > > > > > > > - we need to update the name of "conn_id" somehow, make
> > > conn_id
> > > > > unique
> > > > > > > > (this "poor" HA has been a source of confusion in the
> > past)
> > > > > > > >
> > > > > > > > There are similar problems for the DAG run -- the spec
> > has the
> > > > > > > type as
> > > > > > > > an integer, but everything else about the Airflow system
> > uses
> > > > the
> > > > > > > > (unique) run_id parameter, and I would expect the API to
> > use
> > > > > > > that. The
> > > > > > > > autoinc. id on the run column is literally never used in
> > the
> > > > code
> > > > > > > > base, so exposing that via the API seems odd.
> > > > > > > >
> > > > > > > > A few other smaller points:
> > > > > > > >
> > > > > > > > EventLog: Those are "audit"/action logs, so we probably
> > > > shouldn't
> > > > > let
> > > > > > > > people delete them via the API!
> > > > > > > >
> > > > > > > > pool_id: still an integer. It should be the "name".
> > > > > > > >
> > > > > > > > How should add/delete variables and connections work in
> > the
> > > API
> > > > > with
> > > > > > > > the addition of the new "Secrets Backends"?
> > > > > > > >
> > > > > > > > xcomValues: task_id is listed as an integer.
> > > > > > > >
> > > > > > > >
> > > > > > > > -ash
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> > ===============================================================================
> > > > > > > Please access the attached hyperlink for an important
> > electronic
> > > > > > > communications disclaimer:
> > > > > > >
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> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> > ===============================================================================
> > > > > > >
> > > > >
> > > >
> > > >
> > > > --
> > > >
> > > > Jarek Potiuk
> > > > Polidea
> > <https://kor01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.polidea.com%2F&data=02%7C01%7Clamblin%40coupang.com%7Cd8716c2432c54849f3d708d7e08b68f2%7Ce3098f96361b47c6a9f4ab7bafcaffe9%7C0%7C0%7C637224761681223746&sdata=tMOZFKjLGoXh9eAVW5rXhmJeJw8kYhlWAfwFICN%2Fpfw%3D&reserved=0>
> > | Principal Software Engineer
> > > >
> > > > M: +48 660 796 129 <+48660796129>
> > > > [image: Polidea]
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