Helm chart/v1

[djjudas21]

This PR is an extension of the work in #2576 (thanks @Scizoo88)

This PR adds a Helm chart which deploys ZenBot and MongoDB with default settings. Instead of having to pass in a conf.js file, the individual settings are modelled as yaml data in values.yaml and can be overridden in the usual way for Helm charts.

I have tested this in MicroK8s - it successfully creates a MongoDB server and a ZenBot job running with dummy config. The job runs one-shot so when your trading period / sim finishes and ZenBot exits, Kubernetes does not restart the job!

To consider/discuss before merging:

• Hosting a Helm chart repo so this chart can be used easily

[Scizoo88]

@djjudas21 Thanks for your updates to the chart.

[djjudas21]

I'm running into a problem. Zenbot starts up normally but after some time, it crashes with this error:

/app/node_modules/mongodb/lib/utils.js:132
      throw err;
      ^

MongoError: limit requires an integer
    at Function.create (/app/node_modules/mongodb-core/lib/error.js:43:12)
    at Cursor.limit (/app/node_modules/mongodb/lib/cursor.js:636:22)
    at /app/commands/trade.js:426:66
    at result (/app/node_modules/mongodb/lib/utils.js:414:17)
    at executeCallback (/app/node_modules/mongodb/lib/utils.js:406:9)
    at handleCallback (/app/node_modules/mongodb/lib/utils.js:128:55)
    at cursor.close (/app/node_modules/mongodb/lib/operations/cursor_ops.js:211:62)
    at handleCallback (/app/node_modules/mongodb/lib/utils.js:128:55)
    at completeClose (/app/node_modules/mongodb/lib/cursor.js:893:14)
    at _endSession (/app/node_modules/mongodb/lib/cursor.js:904:37)
    at Cursor._endSession (/app/node_modules/mongodb-core/lib/cursor.js:194:5)
    at Cursor._endSession (/app/node_modules/mongodb/lib/cursor.js:226:59)
    at Cursor.close (/app/node_modules/mongodb/lib/cursor.js:904:19)
    at cursor._next (/app/node_modules/mongodb/lib/operations/cursor_ops.js:211:23)
    at handleCallback (/app/node_modules/mongodb-core/lib/cursor.js:203:5)
    at _setCursorNotifiedImpl (/app/node_modules/mongodb-core/lib/cursor.js:561:38)
    at self._endSession (/app/node_modules/mongodb-core/lib/cursor.js:569:46)
    at ClientSession.endSession (/app/node_modules/mongodb-core/lib/sessions.js:129:41)
    at Cursor._endSession (/app/node_modules/mongodb-core/lib/cursor.js:189:13)
    at Cursor._endSession (/app/node_modules/mongodb/lib/cursor.js:226:59)
    at _setCursorNotifiedImpl (/app/node_modules/mongodb-core/lib/cursor.js:569:17)
    at setCursorNotified (/app/node_modules/mongodb-core/lib/cursor.js:561:3)

I don't know anything about the Zenbot internals but is this something to do with passing in an integer config value as a string? Using Kubernetes to set environment variables casts everything as a string. If this is that problem, it probably means I can't carry on with this approach.

[Scizoo88]

Have you tried to remove the "quote" in the deployment.yaml file?

[djjudas21]

Yes, the quote is required because all values in an env hash must be strings. You have to quote integers and booleans, otherwise it throws an error.

[Scizoo88]

Ok that's unfortunate. I guess the only other option to configure the conf.json via values.yaml would be to still bundle the conf.js with the chart but add as example:

c.mongo.db = process.env.ZENBOT_MONGODB_DATABASE || **{{ .Values.env.ZENBOT_MONGODB_DATABASE }}** || 'zenbot4'

Then in the Configmap use the "tpl" function:

{{ **tpl** (.Files.Get "resources/conf-sample.js") . | indent 4 }}

Remove the env declaration from the deployment.yaml file.

[djjudas21]

Ah, I didn't know about the tpl function - thanks. I'll try this out a bit later :+1:

[djjudas21]

I've pushed a lot more work into this. The two main changes are that the config is now managed as structured yaml which Helm uses to write out conf.js, and that the chart now runs ZenBot as a one-shot Job instead of a Deployment. This is so when ZenBot exits at the end of a sim etc, Kubernetes doesn't dive in and restart it. That could be very undesirable behaviour in a live environment where ZenBot has quit to prevent a loss, etc.

[stale[bot]]

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