INVALID_ARGUMENT (400 error) when calling Stackdriver Error Reporting API - stackdriver

Question

When trying to invoke the Stackdriver Error Reporting API (via the API explorer or via the Client-Side JavaScript library), I receive the following error:
Request:
{ "message" : "test" }
Response:
{
"error": {
"code": 400,
"message": "Request contains an invalid argument.",
"status": "INVALID_ARGUMENT"
}
}
The Stackdriver Error Reporting API is enabled and I have Owner rights to the App Engine project.
Is the API simply not functional? If I'm doing something wrong, can someone try to help?

Answer 1

The documentation for reporting events says that a ServiceContext is required.
If you're only sending a message (not a stacktrace / exception) you'll need to include a context with a reportLocation as well. This is noted in the documentation of the message field, but it's not obvious.
The following works from the API explorer:
{
"context": {
"reportLocation": {
"functionName": "My Function"
}
},
"message": "error message",
"serviceContext": {
"service": "My Microservice",
}
}
You might be interested in the docs on How Error are Grouped too.
FWIW, I work on this product and I think the error message is too generic. The problem is (?) that the serving stack scrubs the message unless they're annotated as being for public consumption. I'll chase that down.