Provide environment at init time

[upgle]

Description

As discussed here, it changes the container proxy to provide an environment at init time (/init).

But I couldn't move the entire context from /run to /init to maintain backward compatibility.

1. /init

Put environment variables in the env field. and runtimes can use this value.

{
  "value": {
    "name" : String,
    "main" : String,
    "code" : String,
    "binary": Boolean,
    "env": Map[String, String] = {
       "__OW_NAMESPACE",
       "__OW_ACTION_NAME",
       "__OW_ACTIVATION_ID",
       "__OW_TRANSACTION_ID",
       "__OW_DEADLINE"
    }
  }
}

2. /run

The namespace, action_name, activation_id, transaction_id, and deadline fields are uppercased and prefixed with "__OW_" by runtimes [1].

• namespace -> __OW_NAMESPACE
• action_name -> __OW_ACTION_NAME

I think these fields cannot be removed due to backward compatibility.

This is a draft pull request, please let me know if there is a better way.

ref

[1] https://github.com/apache/openwhisk/blob/master/docs/actions-actionloop.md#what-the-launcher-needs-to-do

Related issue and scope

https://lists.apache.org/thread.html/ef18f833671a3266d4cde3bf4eaff379596d03b3e147a785a9b06941@%3Cdev.openwhisk.apache.org%3E

My changes affect the following components

• API
• Invoker
• Tests
• Documentation

Types of changes

• Enhancement or new feature (adds new functionality).
• Breaking change (a bug fix or enhancement which changes existing behavior).

Checklist:

• I signed an Apache CLA.
• I reviewed the style guides and followed the recommendations (Travis CI will check :).
• I added tests to cover my changes.
• My changes require further changes to the documentation.
• I updated the documentation where necessary.

[codecov-io]

Codecov Report

Merging #4722 into master will decrease coverage by 6.62%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #4722      +/-   ##
==========================================
- Coverage      85%   78.37%   -6.63%     
==========================================
  Files         198      198              
  Lines        8841     8846       +5     
  Branches      614      619       +5     
==========================================
- Hits         7515     6933     -582     
- Misses       1326     1913     +587

Impacted Files	Coverage Δ
.../openwhisk/core/containerpool/ContainerProxy.scala	93.06% <100%> (+0.1%)	⬆️
...core/database/cosmosdb/RxObservableImplicits.scala	0% <0%> (-100%)	⬇️
...enwhisk/connector/kafka/KamonMetricsReporter.scala	0% <0%> (-100%)	⬇️
...e/database/cosmosdb/cache/ChangeFeedConsumer.scala	0% <0%> (-100%)	⬇️
...ore/database/cosmosdb/cache/CacheInvalidator.scala	0% <0%> (-100%)	⬇️
...core/database/cosmosdb/CosmosDBArtifactStore.scala	0% <0%> (-96.23%)	⬇️
...sk/core/database/cosmosdb/CosmosDBViewMapper.scala	0% <0%> (-93.8%)	⬇️
...tabase/cosmosdb/cache/CacheInvalidatorConfig.scala	0% <0%> (-92.31%)	⬇️
...e/database/cosmosdb/cache/KafkaEventProducer.scala	0% <0%> (-77.78%)	⬇️
...whisk/core/database/cosmosdb/CosmosDBSupport.scala	0% <0%> (-74.08%)	⬇️
... and 14 more

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[rabbah]

This LGTM.

[style95]

LGTM

[chetanmeh]

Thanks @upgle for this 🎉

At times for some web actions I needed the namespace at init time to compute some routing url and then realized that they were only available at run time. With this doing such init time work would be easier