From dfa334650f4d866c1185bd9bf193fb3a80d6ef97 Mon Sep 17 00:00:00 2001
From: Graham McIntire <graham@mcintire.me>
Date: Sat, 7 Feb 2026 12:37:04 -0600
Subject: [PATCH] fix: Improve service startup and Hex installation

- Check if PostgreSQL/Redis already running before starting
- Install Hex and Rebar3 non-interactively on shell entry
- Only run migrations if deps directory exists
- Better error messages with log file locations

This fixes issues when:
- Port 5432 is already in use (existing PostgreSQL)
- Port 6379 is already in use (existing Redis)
- Mix prompts for Hex installation interactively
---
 nix/shell.nix | 89 ++++++++++++++++++++++++++++++---------------------
 1 file changed, 52 insertions(+), 37 deletions(-)

diff --git a/nix/shell.nix b/nix/shell.nix
index 0622223e..c4871a93 100644
--- a/nix/shell.nix
+++ b/nix/shell.nix
@@ -66,21 +66,28 @@ let
     EOF
     fi
 
-    # Start PostgreSQL
-    echo "🐘 Starting PostgreSQL on port ${pgPort}..."
-    ${postgresql_16}/bin/pg_ctl -D ${pgDataDir} -l ${pgDataDir}/logfile -o "-p ${pgPort}" start
+    # Check if PostgreSQL is already running on this port
+    if ${postgresql_16}/bin/pg_isready -h ${pgHost} -p ${pgPort} > /dev/null 2>&1; then
+      echo "✓ PostgreSQL already running on port ${pgPort}"
+    else
+      # Start PostgreSQL
+      echo "🐘 Starting PostgreSQL on port ${pgPort}..."
+      ${postgresql_16}/bin/pg_ctl -D ${pgDataDir} -l ${pgDataDir}/logfile -o "-p ${pgPort}" start
 
-    # Wait for PostgreSQL to be ready
-    for i in {1..30}; do
-      if ${postgresql_16}/bin/pg_isready -h ${pgHost} -p ${pgPort} > /dev/null 2>&1; then
-        break
-      fi
-      if [ $i -eq 30 ]; then
-        echo "❌ PostgreSQL failed to start within 30 seconds"
-        exit 1
-      fi
-      sleep 1
-    done
+      # Wait for PostgreSQL to be ready
+      for i in {1..30}; do
+        if ${postgresql_16}/bin/pg_isready -h ${pgHost} -p ${pgPort} > /dev/null 2>&1; then
+          break
+        fi
+        if [ $i -eq 30 ]; then
+          echo "❌ PostgreSQL failed to start within 30 seconds"
+          echo "    Check ${pgDataDir}/logfile for details"
+          exit 1
+        fi
+        sleep 1
+      done
+      echo "✓ PostgreSQL started successfully"
+    fi
 
     # Create postgres role if it doesn't exist (needed by some tools)
     ${postgresql_16}/bin/psql -h ${pgHost} -p ${pgPort} -U $USER -d postgres -tc \
@@ -102,28 +109,32 @@ let
 
     echo "✓ PostgreSQL started successfully"
 
-    # Start Redis
-    echo "📮 Starting Redis on port ${redisPort}..."
-    mkdir -p ${redisDataDir}
-    ${redis}/bin/redis-server --daemonize yes \
-      --port ${redisPort} \
-      --dir ${redisDataDir} \
-      --save "" \
-      --appendonly no
+    # Check if Redis is already running on this port
+    if ${redis}/bin/redis-cli -p ${redisPort} ping > /dev/null 2>&1; then
+      echo "✓ Redis already running on port ${redisPort}"
+    else
+      # Start Redis
+      echo "📮 Starting Redis on port ${redisPort}..."
+      mkdir -p ${redisDataDir}
+      ${redis}/bin/redis-server --daemonize yes \
+        --port ${redisPort} \
+        --dir ${redisDataDir} \
+        --save "" \
+        --appendonly no
 
-    # Wait for Redis to be ready
-    for i in {1..10}; do
-      if ${redis}/bin/redis-cli -p ${redisPort} ping > /dev/null 2>&1; then
-        break
-      fi
-      if [ $i -eq 10 ]; then
-        echo "❌ Redis failed to start within 10 seconds"
-        exit 1
-      fi
-      sleep 1
-    done
-
-    echo "✓ Redis started successfully"
+      # Wait for Redis to be ready
+      for i in {1..10}; do
+        if ${redis}/bin/redis-cli -p ${redisPort} ping > /dev/null 2>&1; then
+          break
+        fi
+        if [ $i -eq 10 ]; then
+          echo "❌ Redis failed to start within 10 seconds"
+          exit 1
+        fi
+        sleep 1
+      done
+      echo "✓ Redis started successfully"
+    fi
 
     # Mark services as started
     touch ${servicesFlag}
@@ -262,12 +273,16 @@ mkShell {
     # Ensure Erlang can find NIF libraries
     export ERL_AFLAGS="-kernel shell_history enabled"
 
+    # Install Hex and Rebar3 if not already installed
+    mix local.hex --force --if-missing > /dev/null 2>&1
+    mix local.rebar --force --if-missing > /dev/null 2>&1
+
     # Auto-start services on first shell entry
     if [ ! -f "${servicesFlag}" ]; then
       ${startServices}/bin/start-services
 
-      # Run migrations if databases exist
-      if mix ecto.migrate 2>/dev/null; then
+      # Run migrations if databases exist and Mix deps are available
+      if [ -d "deps" ] && mix ecto.migrate 2>/dev/null; then
         echo "✓ Database migrations applied"
       fi
     fi