Datomic Knowledgebase - Questions without answers in Ions

Ion push failing with error message about (missing?, unreadable?) maven artifact ion-1.0.47.jar

Tue, 19 May 2026 19:40:21 +0000

Attempting to push an ion and get an error about not finding (or unable to read) ion-1.0.47.jar. I tried some troubleshooting and I don't think it is a permissions issue, because I am able to use the aws cli and copy ion-0.9.7.jar. So why is 1.0.47 not working?

deps.edn:

{:mvn/repos {"datomic-cloud" {:url "s3://datomic-releases-1fc2183a/maven/releases"}}

 :aliases {
           :ion-dev {:deps {com.datomic/ion-dev {:mvn/version "1.0.352"}
                            com.datomic/client-cloud {:mvn/version "1.0.131"}
                            com.datomic/ion {:mvn/version "1.0.71"}}
                     :main-opts ["-m" "datomic.ion.dev"]}}}

command I'm trying to run:

clojure -M:ion-dev '{:op :push :creds-profile "byt-wrought-test" :region "us-west-2"}'

error:

{:command-failed
 "{:op :push :creds-profile \"byt-wrought-test\" :region \"us-west-2\"}",
 :causes
 ({:message
   "Failed to read artifact descriptor for com.datomic:ion-http-direct:jar:1.0.47",
   :class ArtifactDescriptorException}
  {:message
   "Could not transfer artifact com.datomic:ion-http-direct:pom:1.0.47 from/to datomic-cloud (s3://datomic-releases-1fc2183a/maven/releases): Unexpected error downloading artifact from datomic-releases-1fc2183a",
   :class ArtifactResolutionException}
  {:message
   "Could not transfer artifact com.datomic:ion-http-direct:pom:1.0.47 from/to datomic-cloud (s3://datomic-releases-1fc2183a/maven/releases): Unexpected error downloading artifact from datomic-releases-1fc2183a",
   :class ArtifactTransferException}
  {:message
   "Unexpected error downloading artifact from datomic-releases-1fc2183a",
   :class ExceptionInfo,
   :data
   {:bucket "datomic-releases-1fc2183a",
    :path
    "maven/releases/com/datomic/ion-http-direct/1.0.47/ion-http-direct-1.0.47.pom",
    :reason :cognitect.anomalies/fault}})}

Based on some conversations I found on slack and datomic dev forum, I tried this as a troubleshooting step:

aws --profile byt-wrangle-test s3 cp s3://datomic-releases-1fc2183a/maven/releases/com/datomic/ion/0.9.7/ion-0.9.7.jar .

download: s3://datomic-releases-1fc2183a/maven/releases/com/datomic/ion/0.9.7/ion-0.9.7.jar to ./ion-0.9.7.jar

and that works. But the same attempt with 1.0.47 does not:

aws --profile byt-wrangle-test s3 cp s3://datomic-releases-1fc2183a/maven/releases/com/datomic/ion/1.0.47/ion-1.0.47.jar .
fatal error: An error occurred (403) when calling the HeadObject operation: Forbidden

How to change the default 1 minute jetty async servlet timeout?

Thu, 10 Aug 2023 16:01:07 +0000

We have some ring routes in our HTTP direct ring handler, which returns some Excel files, which are constructed on the fly.

This handler sometimes runs for more than a minute, resulting in the following error:
HTTP ERROR 503 Async servlet timeout URI: /... STATUS: 503 MESSAGE: Async servlet timeout SERVLET: cognitect.http_endpoint.jetty.FnServlet-49bf6f8c Powered by Jetty:// 9.4.48.v20220622

How can we raise this timeout to ~5minutes, which is the maximum timeout of AWS NLBs?

(We are exposing the HTTP direct ion endpoint to the public internet via an AWS NLB, to avoid the 30s timeout and 10MB response payload limit of the AWS API Gateway)

Multiple sources on the internet - eg. https://github.com/ring-clojure/ring/issues/299 - mention a org.eclipse.jetty.server.HttpChannelState.DEFAULT_TIMEOUT Java property which is supposed to affect Jetty's async context timeout.

Since the change of this property at runtime is not picked up by a running jetty instance, we have added provided it as a startup option, via the OverrideSettings CloudFormation template parameter:

`
{:OverrideSettings
(str "export JVM_FLAGS=\"$JVM_FLAGS"

  " -Dclojure.server.repl="
  "{:address,\\\"0.0.0.0\\\",:port,50505,:accept,clojure.core.server/repl}"
  " -Dorg.eclipse.jetty.server.HttpChannelState.DEFAULT_TIMEOUT=300000"
  "\"")}

It is indeed observable within the ion JVM process:
(Long/getLong "org.eclipse.jetty.server.HttpChannelState.DEFAULT_TIMEOUT") => 300000

Yet we are getting a 503 timeout response from the cognitect.http_endpoint.jetty.FnServlet-49bf6f8c servlet after 1 minute still.

Request, which take less then a minute work as expected.

Troubleshooting :deploy-status "FAILED", :code-deploy-status "SUCCEEDED"

Mon, 21 Feb 2022 13:33:43 +0000

After a few days of attempting to launch Datomic Ion on AWS following the Ion Tutorial [0], this appears to be the best I can do:

{:deploy-status "FAILED", :code-deploy-status "SUCCEEDED"}

Searching CloudWatch for “Alert - Alert” reveals no events.

I did not modify the ion-starter codebase except for configuring the correct :endpoint and :app-name. (I believe this was done correctly because I completed all steps in “Develop at the REPL”[1] without a hitch.)

[0]: https://docs.datomic.com/cloud/ions/ions-tutorial.html
[1]: https://docs.datomic.com/cloud/ions/ions-tutorial.html#repl

Thank you for any pointers.

How datomic.client.api/connect work?

Mon, 15 Nov 2021 14:46:44 +0000

I interested how connection work.

When connection is open? (all time or when we call him)
Can we hold connection opened all time ? Is this good or bad?
When we execute any transaction is it updated connection?

maybe the questions are simple, but I would like to better understand how it works.

How do I initialize core.async connections in Datomic Cloud?

Sat, 28 Nov 2020 23:53:01 +0000

I need to "hook up" a core.async channel to a thread on system initialization. How might I go about doing this, or doing any initialization tasks?

Thanks,
Hadil

How can I get a ring-like request in ionized web handlers?

Thu, 26 Nov 2020 19:04:57 +0000

Hello! After hearing the talks and reading the tutorial and documentation, I was under the impression that ions receive their requests in a ring-like format, and that we can "wire a web handler to a single function, using a routing library such as Compojure or pedestal."1

On one hand, this seems to be true with standard ion lambdas, but these are not exposed to the web. OTOH if we want to expose our web service, we need to write a web handler that we'll ionize. When we do that, the requests coming in lose their ring-like shape, and only expose the following keys:

 :headers
 :server-name
 :body
 :datomic.ion.edn.api-gateway/json
 :datomic.ion.edn.api-gateway/data

With that, our router (reitit backed by ring) fails.

I have seen different examples on the web where some router is exposed behind a single web handler, the most promising of which being probably Replion (look at the code) (and he uses reitit and ring and seems to have more success than us) and Pedestal Ions Sample (but Pedestal works in a relaxed ring context).

So my question is: is there something obvious that I don't understand? Are there more working examples? Some people seem to write adapters to transform the requests to make them more ring-like. Are they doing the right thing, or are we all missing something?

For example, here's a very naive adapter:

(defn get-path [req]
  (let [s (get-in req [:datomic.ion.edn.api-gateway/data :requestContext :stage] "stg")
        p (get-in req [:datomic.ion.edn.api-gateway/data :requestContext :http :path] "/")]
    (get (str/split p (re-pattern (str "/" s))) 1 "/"))) ; get rid of stage leading path!

(defn req->ring-req [req]
  (assoc req
         :protocol (get-in req
                           [:datomic.ion.edn.api-gateway/data :requestContext :http :protocol] "HTTP/1.1")
         :remote-addr (get-in req [:headers "host"] "example.com")
         :request-method (keyword
                          (str/lower-case
                           (get-in req [:datomic.ion.edn.api-gateway/data :requestContext :http :method] "GET")))
         :uri (get-path req)))

(defn app
  "Web handler that returns the app's responses for each web request."
  [arg]
  (let [sta (start! arg)
        req (req->ring-req arg)
        ret ((handler/app) req)]
    ret))

Another related question is: what is the :integration key on lambda configurations? Why does "nobody" use it, except Stu's slack event handler? What does it do? We tried setting it and didn't seem to observe an impact.

Thanks!

Bind Ions to IAM roles separate from their ambient compute role

Sun, 25 Oct 2020 19:58:49 +0000

Right now Ions run under the role of the underlying compute resources that they are deployed to. It would be nice to be able to give Ions a role independent of the ambient compute. This can be managed by the Ion runtime machinery by calling AssumeRole in the background, and supplying those creds to the Ions

This is important so that Ions don't have to run with the permissions of all the other ions running in the same compute.

Bind Ions to IAM roles separate from their ambient compute role

Thu, 22 Oct 2020 17:28:02 +0000

This is important so that Ions don't have to run with the permissions of all the other ions running in the same compute.

Allow users to redirect each type of Datomic.ion.cast message to different targets in local dev environment

Thu, 22 Oct 2020 17:06:23 +0000

Ability to direct each ion.cast type (Event, alert, dev, metric) to specific targets in local dev.