Mutation RPC usage

One of the core principals of protoconf is the ability to mutate configs via an API (or RPC). This allows humans and machines work together on the same configuration codebase. protoconf allow humans to code the logic, while machines can only change values via the RPC.

Create a dummy config

// file: ./src/myservice/myconfig.proto
syntax = "proto3";
message MyConfig {
  string name = 1;
  uint32 timeout = 2;
}

"""
file: ./src/myservice/default.pconf
"""
load("myconfig.proto", "MyConfig")

config = MyConfig(name="config")

def main():
    return config

$ protoconf compile .

Create a post-mutation script

$ echo '#!/bin/bash\nprotoconf compile .' > post.sh
$ chmod +x post.sh

Run the mutation server in the background

$ protoconf serve -post ./post.sh . &

Now we will use the protoconf mutate command to hit the mutation RPC

$ protoconf mutate -path myservice/mutation -proto myservice/myconfig.proto -msg MyConfig -field timeout=3

You will now notice a new file created under mutable_config

$ find mutable_config
mutable_config
mutable_config/myservice
mutable_config/myservice/mutation.materialized_JSON

load the mutated values

"""
file: ./src/myservice/default.pconf
"""
load("myconfig.proto", "MyConfig")
load("mutable:myservice/mutation", "value")

config = MyConfig(name="config", timeout=value.timeout)

def main():
    return config

Run the protoconf mutate command again with different value and watch how your configs changes.

Next steps

Running in production

The protoconf serve command accepts -pre and -post scripts which should be used for preparing the ground for writing the mutation (-pre) and followup actions to run after writing the mutation (-post).

Both scripts will run by protoconf serve on every mutation. The scripts will be receiveing a metadata string as its first argument ($1 in bash) and can be used to pass metadata from the initiator of the rpc to the script, This can be used to pass a token for github to validate the initiator or to pass more context to be added to the commit message.

These scripts should handle the git lifecycle of the mutation (setting the workspace to latest ref, and push the result after the writing done.)

compiling the configs should be part of the -post script.

When running in HA, you can use these scripts to acquire a lock from consul/etcd.

Using gRPC

The mutation proto is available here.