We are using Apigee Cloud Edgeand want to log some additional information about our requests. The Syslog policy seems ideal, but I want to ensure that the log messages are encrypted over the wire. Is this possible using the policy.
Alternatively, I can expose a logging service in our back end and log over https: but I don't want to slow things down with a synchronous call.
Any thoughts on the best way to achieve this?
No. The syslog policy does not encrypt.
To use your own service to receive data asynchronously, you can try a service callout policy in the PostFlow - Response section of a proxy and make it asynchronous by setting async="true" attribute in the policy XML.
Some variables however (e.g. request-scoped default variables) are not available in the PostFlow. So you may need to create your own variables at appropriate point in the flow to log correctly.