TaylorCFrey commented on a change in pull request #5910: URL: https://github.com/apache/trafficcontrol/pull/5910#discussion_r645176789
########## File path: blueprints/refetch-invalidation.md ########## @@ -0,0 +1,240 @@ +<!-- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> +# Add REFETCH capability option for Content Invalidation + +## Problem Description + +Currently, within ATC, there is a concept of Invalidation Jobs. These Invalidation Jobs give a user the ability to queue an invalidation for a resource, primarily based on regular expressions. The invalidation is gathered and treated as though there was a cache **STALE**, allowing the cache to query the origin server to **REFRESH** the resource. However, should the cache policy still be incorrect or misconfigured, the resource could be updated on the origin server, but the cache will still receive a 304 - Not Modified HTTP status response. + +## Proposed Change + + To address this potential conflict, a proposal to add **REFETCH** as an option for Invalidation Jobs. This will then be treated by caches as a **MISS** (rather than a **STALE**), thusly allowing the cache to retrieve the resource regardless of cache policies. The original **REFRESH**/**STALE** will be the default option, where **REFETCH**/**MISS** will be the addition. + +### Traffic Portal Impact + +##### Create and Update +Traffic Portal will need to update the Invalidation Job to account for the different options. When creating an Invalidation Job both options will need to be present (Perhaps a radio button? Default will be the original **REFRESH**). + +Tooltips should be added to ensure an understanding of this feature at a high level. + +##### Read +When displaying the information, the **Invalidation Requests** table current shows the `Parameters` field, so the display will be straight forward with no manipulation. + +However, we derived and calculate the expiration field based on the TTL. This code will need to be modified to account for the additional information contained in the `Parameters` field. + +### Traffic Ops Impact + +Both the API and the database schema will likely be updated, which in turn will result in changes downstream (such as T3C/ORT, clients) as well. + +#### REST API Impact + +No new endpoints will be required. However the current invalidation job will now include an optional field during `Create`. Invalidation jobs are added by submitting a POST to the jobs endpoint. + +**POST** /api/4.0/jobs + +##### Current Request + +Body: +``` +{"startTime":"2021-06-02T15:23:21.348Z","deliveryService":11,"regex":"/path/.*\\.jpeg","ttl":24} +``` + +Which is mapped to a go `struct` in the `go-tc` lib. +```go +type InvalidationJobInput struct { + DeliveryService *interface{} `json:"deliveryService"` + Regex *string `json:"regex"` + StartTime *Time `json:"startTime"` + TTL *interface{} `json:"ttl"` + dsid *uint + ttl *time.Duration +} +``` + +##### Proposed + +Add an "InvalidationType" to signify a specific type of invalidation request. The InvalidationType is an optional field and will not break backwards compatibility with previous API versions. If the field is included, it _must_ be either "refetch" or "refresh". + +Body: +``` +{"startTime":"2021-06-02T15:23:21.348Z","deliveryService":11,"regex":"/path/.*\\.jpeg","ttl":24,"invalidationType":"refresh"} +``` + +This struct now contains the `InvalidationType *string` field. +```go +type InvalidationJobInput struct { + DeliveryService *interface{} `json:"deliveryService"` + Regex *string `json:"regex"` + InvalidationType *string `json:"invalidationType,omitempty"` + StartTime *Time `json:"startTime"` + TTL *interface{} `json:"ttl"` + dsid *uint + ttl *time.Duration +} +``` + +##### Parsing the value + +Since the field is optional and existing functionality only signifies a **REFRESH**/**STALE** capability, if the field is omitted, empty, malformed, or in any way _not_ `refetch` then it will be treated as `refresh`. + +##### Response + +The response will be modified, then, to return this new value as well. + +Sample current response: +``` +{"alerts":[{"text":"Invalidation request created for http://amc-linear-origin.local.tld/path/.*\\.jpeg, start:2021-06-02 15:23:21.348 +0000 UTC end 2021-06-03 15:23:21.348 +0000 UTC","level":"success"}],"response":{"assetUrl":"http://amc-linear-origin.local.tld/path/.*\\.jpeg","createdBy":"admin","deliveryService":"amc-live","id":1,"keyword":"PURGE","parameters":"TTL:24h""startTime":"2021-06-02 09:23:21-06"}} +``` + +Sample new response (includes the `invalidationType` on parameters field): +``` +{"alerts":[{"text":"Invalidation request created for http://amc-linear-origin.local.tld/path/.*\\.jpeg, start:2021-06-02 15:23:21.348 +0000 UTC end 2021-06-03 15:23:21.348 +0000 UTC","level":"success"}],"response":{"assetUrl":"http://amc-linear-origin.local.tld/path/.*\\.jpeg","createdBy":"admin","deliveryService":"amc-live","id":1,"keyword":"PURGE","parameters":"TTL:24h,invalidationType:refresh","startTime":"2021-06-02 09:23:21-06"}} +``` + +___ + +> Note: There are still 1.x routes that reference `UserInvalidationJob`, such as + `user/current/jobs(/|\.json/?)?$` + `user/current/jobs(/|\.json/?)?$` + These routes are currently deprecated and the corresponding `structs` will be removed in a future release as well. + +#### Client Impact + +Likewise with Traffic Portal, the `go` clients will need to be updated to provide this additional functionality. Since an additional field has been added to `InvalidationJobInput` in `go-tc` lib, this can be set by the client as well. If left unset, it will default to "refresh". + +#### Data Model / Database Impact + + +The current column `parameters` will now contain a cskv (comma separated key value) string. Currently it only stores the `TTL` for the invalidation request: +``` +TTL:48h +``` + +Moving forward, this column will also contain the type of cache invalidation. For instance, the string may read: +``` +TTL:48h,invalidationType:refetch +``` + +If there is no `invalidationType` in the cskv, it is assumed to be **REFRESH**/**STALE** as it's default value keeping with the current implementation. Otherwise the `invalidationType` will be either `refetch` or `refresh`, defaulting to `refresh` during validation. + +*OPTIONAL, BUT RECOMMENDED*: As part of this effort, the _Boy Scout Rule_ will be applied ("Always leave the campground cleaner than you found it."). The `agent`, `status`, `asset_type`, `object_type`, and `object_name` columns will be removed. `agent` and `status` are currently hardcoded to the value of 1. Similarly, `asset_type` is never a anything besides "file". `object_type` and `object_name` are not used at all. This would require a DB migration with Goose as well. If this were not implemented, no migration is necessary. + +> The removal of these columns will impact the `UserInvalidationJob` struct. Even though the only endpoint utilizing this struct (v1.1) is deprecated, it is still in use. + +### ORT/T3C Impact + +The `regexrevalidatedotconfig.go` in _lib/tc-atscfg_ currently has a function called `filterJobs` that is responsible for parsing the _parameters_ information from the job. Right now, that is only parsing the **TTL**, however it would then also need to parse the optional, extra field of **invalidationType**. + +```go +type revalJob struct { + AssetURL string + PurgeEnd time.Time + Type string // MISS or STALE (default) +} +``` + +As we can see above, if the value **invalidationType** is missing or equal to **refresh**, then the `revalJob` struct's `Type` field will be set to **STALE**. Otherwise, if the **invalidationType** is **refetch** then the `Type` field will be set to **MISS**. The struct is already prepared for this information, it needs only to be parsed by during the `filterJobs` function call. + + +### Traffic Monitor Impact + +N/A - No changes + +### Traffic Router Impact + +N/A - No changes + +### Traffic Stats Impact + +N/A - No changes + +### Traffic Vault Impact + +N/A - No changes + +### Documentation Impact + +This information will need to be added to the current **Forcing Content Invalidation** section under the **_Quick How To Guides_** section under the **_Administrator's Guide_** +[Content Invalidation](https://traffic-control-cdn.readthedocs.io/en/latest/admin/quick_howto/content_invalidation.html) + +Additionally, the **_Traffic Ops API_** `jobs` routes will need to be updated with the changes, API V1-V4. +[V4 Jobs](https://traffic-control-cdn.readthedocs.io/en/latest/admin/quick_howto/content_invalidation.html) + +### Testing Impact + +##### Unit tests + +For ORT/T3C there are already unit tests that will need to be updated to account for this contingency. + +Update: +``` +github.com/apache/trafficcontrol/lib/go-atscfg/regexrevalidatedotconfig_test.go +``` + +There are no unit tests for invalidation jobs in `traffic_ops_golang`. This provides an opportunity to create unit tests to validate current and new functionality. + +Add: +``` +github.com/apache/trafficcontrol/traffic_ops/traffic_ops_golang/invalidationjobs/invalidationjobs.go +``` + +##### Integration/E2E Tests: +There are already existing integration tests for the various APIs (v1-v4) for Traffic Ops. Each will need to have this optional functionality tested as well. +``` +github.com/apache/trafficcontrol/traffic_ops/testing/api/v1/jobs_test.go +github.com/apache/trafficcontrol/traffic_ops/testing/api/v2/jobs_test.go +github.com/apache/trafficcontrol/traffic_ops/testing/api/v3/jobs_test.go +github.com/apache/trafficcontrol/traffic_ops/testing/api/v4/jobs_test.go +``` + +### Performance Impact + +There will be no performance impact for Traffic Control. + +> Note: This functionality may create a performance impact on caches that implement a REFETCH/MISS manual override based on a regex. + +### Security Impact + +The validation in Traffic Ops of the `invalidationType` field will be such that it can only be explicitly set to **refetch**. Any other value (missing, malformed, wrong data type, etc.) will result in either a 400 level error or a default to **refresh**. No other permissions are modified. Review comment: Oh excellent question. What are your thoughts? I suppose I would probably make this a bit more strict. To be explicitly correct, the caller would have to send either `refetch`, `refresh`, or nothing at all. By that I mean they would not include the `invalidationType` key at all (which would then default to `refresh`). If they did include the key and the value was an empty string, that would result in a 400. In fact, any other value would result in a 400. I think this is probably the best approach. The response can contain a helpful message to why it was rejected to assist any callers in the future. Should it be case *in*sensitive? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
![http://amc-linear-origin.local.tld/path/.*\\.jpeg","createdBy":"admin","deliveryService":"amc-live","id":1,"keyword":"PURGE","parameters":"TTL:24h""startTime":"2021-06-02](http://amc-linear-origin.local.tld/path/.*\\.jpeg","createdBy":"admin","deliveryService":"amc-live","id":1,"keyword":"PURGE","parameters":"TTL:24h""startTime":"2021-06-02){kind=link}
![http://amc-linear-origin.local.tld/path/.*\\.jpeg","createdBy":"admin","deliveryService":"amc-live","id":1,"keyword":"PURGE","parameters":"TTL:24h,invalidationType:refresh","startTime":"2021-06-02](http://amc-linear-origin.local.tld/path/.*\\.jpeg","createdBy":"admin","deliveryService":"amc-live","id":1,"keyword":"PURGE","parameters":"TTL:24h,invalidationType:refresh","startTime":"2021-06-02){kind=link}