use local config-encyrption in start-flow.sh

The oauth edge function had been hard coded to call the production
conifg encryption service. This fixes that so that local installs
now exclusively use the local config encryption serivce that's started
by `start-flow.sh`. This unfortunately required a rather dirty
hack to allow the oauth function, which is run by the supabase
cli inside their docker container, to connect to the local config
encryption service. That hack will likely remain until we can change
how the oauth function is deployed.

local/start-component.sh

@@ -65,6 +65,14 @@ function project_dir() {
 
 function start_config_encryption() {
     cd "$(project_dir 'config-encryption')"
+
+    # This is part of a hack to allow the oauth edge function to call the config-encryption service locally.
+    # The _other_ part of the hack is down in `start_oauth_edge`.
+    # This container exists to do nothing other than to attach to the supabase docker network and expose port 8765, which
+    # is what config-encryption listens on. The pause container exists for just these kinds of shennanigans.
+    # Per: https://stackoverflow.com/a/44739847 the `docker start` will return 0 if the container is already running
+    docker start config_encryption_hack_proxy || \
+         must_run docker run --rm --name config_encryption_hack_proxy -p 8765 --network supabase_network_flow --detach google/pause:latest
     must_run cargo run -- --gcp-kms "$TEST_KMS_KEY"
 }
 
@@ -132,7 +140,22 @@ function start_control_plane_agent() {
 
 function start_oauth_edge() {
     cd "$(project_dir 'flow')"
-    must_run supabase functions serve oauth
+    # We need to do some weird crap to allow the oauth edge function to connect to the config-encryption
+    # service running on localhost (outside of docker). The hostname that's used for config-encyrption
+    # will be set to the gateway IP of the docker network. A dummy container, which is attached to that network
+    # and listening on port 8765, ensures that port 8765 will be exposed on the host at that address.
+    # Determine the gateway IP of the supabase docker network:
+    local gateway_ip="$(docker network inspect supabase_network_flow -f '{{ (index .IPAM.Config 0).Gateway }}' )"
+    # lol I guess this is a way to trim whitespace from a bash variable: https://stackoverflow.com/a/12973694
+    gateway_ip="$(echo "$gateway_ip" | xargs echo )"
+    if [[ -z "$gateway_ip" ]]; then
+        bail "unable to determine docker network gateway ip"
+    fi
+    # put this file in /var/tmp/ because macs have issues mounting other files into a docker container, which is
+    # what I _think_ supabase functions serve is doing?
+    echo "CONFIG_ENCRYPTION_URL=http://${gateway_ip}:8765/v1/encrypt-config" > /var/tmp/config-encryption-hack-proxy-addr
+    must_run supabase functions serve oauth --env-file /var/tmp/config-encryption-hack-proxy-addr
+
 }
 
 function start_schema_inference() {

supabase/functions/oauth/encrypt-config.ts

@@ -3,8 +3,17 @@ import { corsHeaders } from "../_shared/cors.ts";
 import { returnPostgresError } from "../_shared/helpers.ts";
 import { supabaseClient } from "../_shared/supabaseClient.ts";
 
-const ENCRYPTION_SERVICE =
-  "https://config-encryption.estuary.dev/v1/encrypt-config";
+const config_encryption_url = () => {
+  const env = Deno.env.get('CONFIG_ENCRYPTION_URL');
+  // A more principled approach would be to require that this url is always provided by the
+  // env var. But that would require using a supabase secret to set the value in prod,
+  // and _that_ seemed like a whole ordeal that I don't have time for right now.
+  if (env) {
+    return env
+  } else {
+    return "https://config-encryption.estuary.dev/v1/encrypt-config"
+  }
+}
 
 const CREDENTIALS_KEY = "credentials";
 
@@ -58,7 +67,7 @@ export async function encryptConfig(req: Record<string, any>) {
 
   const { endpoint_spec_schema } = connectorTagData as ConnectorTagsResponse;
 
-  const response = await fetch(ENCRYPTION_SERVICE, {
+  const response = await fetch(config_encryption_url(), {
     method: "POST",
     body: JSON.stringify({
       config,