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Diffstat (limited to 'README.md')
| -rw-r--r-- | README.md | 28 |
1 files changed, 25 insertions, 3 deletions
@@ -62,18 +62,25 @@ Imagine the following code: ```clojure (defn post-handler [user-input] (let [db-item (process user-input) - ext-ref (clj-http.client/post ext-service {...})] ; may throw exception + ext-ref (clj-http.client/post ext-service {:connection-timeout 3000 ; timeout in milliseconds + :socket-timeout 10000 ; timeout in milliseconds + ...})] ; may throw exception @(d/transact conn [(assoc db-item :some/ext-ref ext-ref)]))) ``` What if the POST request fails? Should it be retried? For how long? Should it be allowed to fail? How do you then process failures later? +PS: If you do not set connection/socket-timeout, there is a chance that +clj-http/client will wait for all eternity in the case of a dropped TCP connection. + The queue way to solve this would be: ```clojure (defn get-ext-ref [{:keys [id]}] - (let [ext-ref (clj-http.client/post ext-service {...})] ; may throw exception + (let [ext-ref (clj-http.client/post ext-service {:connection-timeout 3000 ; timeout in milliseconds + :socket-timeout 10000 ; timeout in milliseconds + ...})] ; may throw exception @(d/transact conn [[:db/cas [:some/id id] :some/ext-ref nil @@ -82,7 +89,7 @@ The queue way to solve this would be: (yq/add-consumer! :get-ext-ref get-ext-ref {:allow-cas-failure? true}) (defn post-handler [user-input] - (let [{:some/keys [id] :as db-item} (process user-input) + (let [{:some/keys [id] :as db-item} (process user-input)] @(d/transact conn [db-item (yq/put :get-ext-ref {:id id})]))) ``` @@ -371,6 +378,21 @@ Note: I have not tried these libraries myself. ## Change log +#### 2022-08-18 v0.2.60 [diff](https://github.com/ivarref/yoltq/compare/v0.2.59...v0.2.60) +Improved: Added config option `:healthy-allowed-error-time`: +``` + ; If you are dealing with a flaky downstream service, you may not want + ; yoltq to mark itself as unhealthy on the first failure encounter with + ; the downstream service. Change this setting to let yoltq mark itself + ; as healthy even though a queue item has been failing for some time. + :healthy-allowed-error-time (Duration/ofMinutes 15) +``` + +#### 2022-08-15 v0.2.59 [diff](https://github.com/ivarref/yoltq/compare/v0.2.58...v0.2.59) +Fixed: +* Race condition that made the following possible: `stop!` would terminate the slow thread +watcher, and a stuck thread could keep `stop!` from completing! + #### 2022-06-30 v0.2.58 [diff](https://github.com/ivarref/yoltq/compare/v0.2.57...v0.2.58) Slightly more safe EDN printing and parsing. Recommended reading: |