Developed by google (2015). It uses HTTP/2 for transport, Protocol Buffers as the default interface description language
IDL is a generic term for a language that lets a program or object written in one language communicate with another program written in an unknown language. IDLs describe an interface in a language-independent way, enabling communication between software components that do not share one language, for example, between those written in C++ and those written in Java.
Popular IDL used with gRPC Apache Thrift (by Facebook), Apache Avro, Flatbuffers (by Google)
Why do you mean by HTTP/2 for transport? gRPC doesn't have any components of HTTP like url, method, headers so HTTP?
That's not entirely true. gRPC use HTTP components like URL path, request/response headers (content-type, timeout, custom-metadata) behind the scenes to make the rpc call! Most importantly it uses HTTP 2 streams to make multiple RPC requests within a single TCP connection with support for stream cancellation etc. refer PROTOCOL-HTTP2.
What happens to the channel when the server goes down? Does it reresolve the DNS to obtain new address and retry the rpc?
yes, using gRPC reflections. gRPC Server Reflection provides information about publicly-accessible gRPC services on a server, and assists clients at runtime to construct RPC requests and responses without precompiled service information.
evans is a generic gRPC command line client which uses either gRPC server reflection or proto files to construct, decode RPC request, response
