DynamoDB Dynomite Debugging Tips

Important: These docs are for the outdated Jets 5 versions and below. For the latest Jets docs: docs.rubyonjets.com

Also, you can configure Dynomite.config.log_level = :debug. This will show the raw API request and response payload within aws-sdk-dynamodb gem.

config/initializers/dynomite.rb

Dynomite.configure do |config|
  config.log_level = :debug
end

You can turn on the DYNOMITE_DEBUG flag for even more debugging output. Dynomite shows what parameters are being sent by dynomite to the DynamoDB Ruby SDK API.

export DYNOMITE_DEBUG=1

Example

Jets booting up in development mode!
> Product.where(category: "Electronics", sku: 101).to_a
Index used primary_key (fields: category, sku))
Dynomite::Item::Query::Relation#perform query
{:expression_attribute_names=>{"#category"=>"category", "#sku"=>"sku"},
:expression_attribute_values=>{":category"=>"Electronics", ":sku"=>101},
:key_condition_expression=>"#category = :category AND #sku = :sku",
:table_name=>"demo-dev_products"}
D, [2023-08-03T22:42:24.610218 #179859] DEBUG -- : query | Request "{\"ExpressionAttributeNames\":{\"#category\":\"category\",\"#sku\":\"sku\"},\"ExpressionAttributeValues\":{\":category\":{\"S\":\"Electronics\"},\":sku\":{\"N\":\"101\"}},\"KeyConditionExpression\":\"#category = :category AND #sku = :sku\",\"TableName\":\"demo-dev_products\"}" | Response "{\"Count\":1,\"Items\":[{\"updated_at\":{\"S\":\"2023-08-03T16:17:50Z\"},\"created_at\":{\"S\":\"2023-08-03T16:17:50Z\"},\"name\":{\"S\":\"Smartphone\"},\"stock_quantity\":{\"N\":\"50\"},\"category\":{\"S\":\"Electronics\"},\"price\":{\"N\":\"500\"},\"sku\":{\"N\":\"101\"}}],\"ScannedCount\":1}"
=>
[#<Product:0x00007f14cb52f418
  @attrs={"updated_at"=>"2023-08-03T16:17:50Z", "created_at"=>"2023-08-03T16:17:50Z", "name"=>"Smartphone", "stock_quantity"=>0.5e2, "category"=>"Electronics", "price"=>0.5e3, "sku"=>0.101e3},
  @new_record=false>]
>

Note there are also describe_table calls made to discover indexes and use query instead of the scan method when possible. Once indexes are discovered, they are cached, and the describe_table no longer needs to be called.

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