Passing Default Arguments in GreenGrass recipe, fails to do so on IoT Edge device

Question

Problem passing arguments with non alpha chars, being 'ignored'

When I configure a component with an argument, as below
"ComponentConfiguration": {
		"DefaultConfiguration": {
			"Slot": "1-2-3-4"
		}
	},

At the end, when the pythonscript is being launched using that argument, say: 
	"Run": "python {artifacts:decompressedPath}/program/myscript.py \"{configuration:/Slot}\""

At the Edge device it is being passed as myscript 1 <------------missing -2-3-4

It seems documentation is missing, I need more arguments being passed into 'Slot' but not filtered by some unknown mechanism.
How to solve it? Spaces and comma's have been tried already.

THANKS

Answer

Hi enierop,

First, can you check your `/config/config.tlog`? This is a transaction log that contains all the configuration that has been applied.

By checking the config.tlog for `Slot` and your component lifecycle, you can see what Greengrass thinks is the value and what it will run:

e.g.
```
#  grep Slot /greengrass/v2/config/config.tlog
{"TS":1647492231773,"TP":["services","com.example.HelloWorld","configuration","Slot"],"W":"changed","V":"1-2-3-4"}
# grep Run /greengrass/v2/config/config.tlog
{"TS":1647492236124,"TP":["services","com.example.HelloWorld","lifecycle","Run"],"W":"changed","V":"python3 /greengrass/v2/packages/artifacts/com.example.HelloWorld/1.1.2/hello_world.py \"1-2-3-4\""}
```

Is it possible that you deployed an earlier version of your component that contained the `"DefaultConfiguration"` value of `"1"` for the `Slot` parameter?

Greengrass does not do any interpretation of the data when it replaces the values in the recipe. However, if you had previously set the default configuration to a value, like 1, then that value would be used unless the configuration is reset via a deployment.

If you change the `DefaultConfiguration` value from one version of a recipe to another, and you want that new default to be applied, in the deployment you must also add configuration to reset the config. For instance, in your deployment, if you configure the component with:
```
  "reset": [
    ""
  ]
```
it will reset all the applied configuration back to the defaults.

---

The following is my attempt to replicate your issue. I have installed Greengrass v2.5.3 and python3.8.10. I created a python3 script `hello_world.py` which contains the following:
```python
import sys

message = "Hello, %s!" % sys.argv[1]
print(message)
```

I created a recipe that looks like:
```
{
  "RecipeFormatVersion": "2020-01-25",
  "ComponentName": "com.example.HelloWorld",
  "ComponentVersion": "1.1.2",
  "ComponentType": "aws.greengrass.generic",
  "ComponentDescription": "Hello world",
  "ComponentPublisher": "Me",
  "ComponentConfiguration": {
    "DefaultConfiguration": {
      "Slot": "1-2-3-4"
    }
  },
  "Manifests": [
    {
      "Platform": {
        "os": "linux"
      },
      "Name": "Linux",
      "Lifecycle": {
        "Run": "python3 {artifacts:path}/hello_world.py \"{configuration:/Slot}\""
      },
      "Artifacts": [
        {
          "Uri": "s3:///hello_world.py",
          "Unarchive": "NONE",
          "Permission": {
            "Read": "OWNER",
            "Execute": "NONE"
          }
        }
      ]
    }
  ]
}
```

It prints out "Hello, 1-2-3-4!" when it runs:
```
2022-03-17T04:43:56.347Z [INFO] (Copier) com.example.HelloWorld: stdout. Hello, 1-2-3-4!. {scriptName=services.com.example.HelloWorld.lifecycle.Run, serviceName=com.example.HelloWorld, currentState=RUNNING}
```

When I change the value of "Slot" in the DefaultConfiguration and update the recipe and component version, using `reset: [""] ` always makes it print the expected response.

Answer

Thanks, It once was "1" indeed. 
In the tlog it shows first as one
{"TS":1646767501143,"TP":["services","com.mystuff","configuration","Slot"],"W":"changed","V":"1"}

Later it becomes
{"TS":1646927815345,"TP":["services","com.mystuff","configuration","Slot"],"W":"timestampUpdated","V":null}

Unfortunately, the argument in Python, I used it the same as you, but it stays "1".

I will try your suggestions, though I must say, it does not make any sense to me that it does not detect argument changes. I will (need to) be doing this more often.

Passing Default Arguments in GreenGrass recipe, fails to do so on IoT Edge device

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