fix: resolve SC2059 shellcheck warnings in gateway demo

Replace printf format strings that embedded shell variables with
proper format specifiers and variable arguments. All color variables
are now passed as separate arguments using '%s' format specifiers,
which satisfies shellcheck SC2059.

Author: ericcurtin

demos/gateway/demo.sh

@@ -56,10 +56,10 @@ run_step() {
     local command="$2"
 
     echo
-    printf "${dim}# %s${reset}\n" "$description"
-    printf "${bold}${green}\$${reset} "
+    printf '%s# %s%s\n' "${dim}" "$description" "${reset}"
+    printf '%s%s$%s ' "${bold}" "${green}" "${reset}"
     typewrite "$command" 0.035
-    printf "${dim} ▌${reset}"   # blinking-cursor illusion
+    printf '%s ▌%s' "${dim}" "${reset}"   # blinking-cursor illusion
 
     # Wait for Enter
     read -r -s _
@@ -73,21 +73,21 @@ run_step() {
 pause_comment() {
     local msg="$1"
     echo
-    printf "${dim}# %s${reset}" "$msg"
+    printf '%s# %s%s' "${dim}" "$msg" "${reset}"
     read -r -s _
     echo
 }
 
 # Section banner
 section() {
     echo
-    printf "${bold}${blue}┌──────────────────────────────────────────────────────┐${reset}\n"
-    printf "${bold}${blue}│  %-52s│${reset}\n" "$*"
-    printf "${bold}${blue}└──────────────────────────────────────────────────────┘${reset}\n"
+    printf '%s%s┌──────────────────────────────────────────────────────┐%s\n' "${bold}" "${blue}" "${reset}"
+    printf '%s%s│  %-52s│%s\n' "${bold}" "${blue}" "$*" "${reset}"
+    printf '%s%s└──────────────────────────────────────────────────────┘%s\n' "${bold}" "${blue}" "${reset}"
 }
 
-ok()  { printf "${green}✓ %s${reset}\n" "$*"; }
-info(){ printf "${cyan}  %s${reset}\n"  "$*"; }
+ok()  { printf '%s✓ %s%s\n' "${green}" "$*" "${reset}"; }
+info(){ printf '%s  %s%s\n' "${cyan}"  "$*" "${reset}"; }
 
 pretty_json() {
     python3 -c "import sys,json; print(json.dumps(json.load(sys.stdin), indent=2))"
@@ -99,7 +99,7 @@ wait_for_gateway() {
     local retries=30
     while ! curl -sf "${GATEWAY_URL}/health" >/dev/null 2>&1; do
         retries=$((retries - 1))
-        [[ $retries -eq 0 ]] && { printf "${red}Gateway did not start${reset}\n"; exit 1; }
+        [[ $retries -eq 0 ]] && { printf '%sGateway did not start%s\n' "${red}" "${reset}"; exit 1; }
         sleep 0.2
     done
 }
@@ -136,7 +136,7 @@ trap 'stop_gateway' EXIT
 # ─────────────────────────────────────────────────────────────────────────────
 
 clear
-printf "${bold}${blue}"
+printf '%s%s' "${bold}" "${blue}"
 cat <<'BANNER'
   ██████╗   ██████╗  ██████╗  ██╗  ██╗ ███████╗ ██████╗
   ██╔══██╗ ██╔═══██╗ ██╔════╝ ██║ ██╔╝ ██╔════╝ ██╔══██╗
@@ -159,10 +159,10 @@ cat <<'BANNER'
   ╚██████╔╝ ██║  ██║    ██║    ███████╗ ╚███╔███╔╝ ██║  ██║    ██║
    ╚═════╝  ╚═╝  ╚═╝    ╚═╝    ╚══════╝  ╚══╝╚══╝  ╚═╝  ╚═╝    ╚═╝
 BANNER
-printf "${reset}\n"
-printf "${dim}  Press ${reset}${bold}Enter${reset}${dim} to advance through each step.${reset}\n"
-printf "${dim}  The gateway is started behind the scenes — commands shown are${reset}\n"
-printf "${dim}  exactly what you would run in a real session.${reset}\n"
+printf '%s\n' "${reset}"
+printf '%s  Press %s%sEnter%s%s to advance through each step.%s\n' "${dim}" "${reset}" "${bold}" "${reset}" "${dim}" "${reset}"
+printf '%s  The gateway is started behind the scenes — commands shown are%s\n' "${dim}" "${reset}"
+printf '%s  exactly what you would run in a real session.%s\n' "${dim}" "${reset}"
 echo
 
 pause_comment "Let's begin — press Enter to start"
@@ -176,7 +176,7 @@ section "Step 1 — Write a gateway config"
 pause_comment "The gateway is driven by a simple YAML file. Here's a basic one."
 
 echo
-printf "${dim}# demos/gateway/config-basic.yaml${reset}\n"
+printf '%s# demos/gateway/config-basic.yaml%s\n' "${dim}" "${reset}"
 cat "${SCRIPT_DIR}/config-basic.yaml"
 
 pause_comment "Press Enter to start the gateway"
@@ -189,12 +189,12 @@ section "Step 2 — Start the gateway"
 
 # Show the pretty command; actually run our binary in the background
 echo
-printf "${dim}# Starts an OpenAI-compatible proxy on :4000${reset}\n"
-printf "${bold}${green}\$${reset} "
+printf '%s# Starts an OpenAI-compatible proxy on :4000%s\n' "${dim}" "${reset}"
+printf '%s%s$%s ' "${bold}" "${green}" "${reset}"
 typewrite "docker model gateway --config demos/gateway/config-basic.yaml" 0.035
-printf "${dim} ▌${reset}"
+printf '%s ▌%s' "${dim}" "${reset}"
 read -r -s _
-printf "\r${bold}${green}\$${reset} ${white}docker model gateway --config demos/gateway/config-basic.yaml${reset}\n"
+printf '\r%s%s$%s %sdocker model gateway --config demos/gateway/config-basic.yaml%s\n' "${bold}" "${green}" "${reset}" "${white}" "${reset}"
 
 # Actually launch
 launch_gateway "${SCRIPT_DIR}/config-basic.yaml"
@@ -230,12 +230,12 @@ section "Step 5 — Auth enforcement"
 pause_comment "The gateway rejects requests with the wrong key"
 
 echo
-printf "${dim}# Wrong key → 401${reset}\n"
-printf "${bold}${green}\$${reset} "
+printf '%s# Wrong key → 401%s\n' "${dim}" "${reset}"
+printf '%s%s$%s ' "${bold}" "${green}" "${reset}"
 typewrite "curl -s -o /dev/null -w '%{http_code}' http://localhost:${GATEWAY_PORT}/v1/chat/completions -H 'Authorization: Bearer WRONG'" 0.03
-printf "${dim} ▌${reset}"
+printf '%s ▌%s' "${dim}" "${reset}"
 read -r -s _
-printf "\r${bold}${green}\$${reset} ${white}curl -s -o /dev/null -w '%%{http_code}' .../v1/chat/completions -H 'Authorization: Bearer WRONG'${reset}\n"
+printf '\r%s%s$%s %scurl -s -o /dev/null -w '\''%%{http_code}'\'' .../v1/chat/completions -H '\''Authorization: Bearer WRONG'\''%s\n' "${bold}" "${green}" "${reset}" "${white}" "${reset}"
 
 HTTP_CODE=$(curl -s -o /dev/null -w "%{http_code}" \
     -X POST "${GATEWAY_URL}/v1/chat/completions" \
@@ -254,16 +254,16 @@ section "Step 6 — Chat completion"
 pause_comment "Standard OpenAI-compatible chat completions endpoint"
 
 echo
-printf "${dim}# POST /v1/chat/completions — non-streaming${reset}\n"
-printf "${bold}${green}\$${reset} "
+printf '%s# POST /v1/chat/completions — non-streaming%s\n' "${dim}" "${reset}"
+printf '%s%s$%s ' "${bold}" "${green}" "${reset}"
 typewrite "curl -s http://localhost:${GATEWAY_PORT}/v1/chat/completions \\" 0.03
-printf "\n"
+printf '\n'
 typewrite "  -H 'Authorization: Bearer ${API_KEY}' \\" 0.03
-printf "\n"
+printf '\n'
 typewrite "  -d '{\"model\":\"smollm2\",\"messages\":[{\"role\":\"user\",\"content\":\"What is Docker Model Runner?\"}],\"max_tokens\":80}'" 0.03
-printf "${dim} ▌${reset}"
+printf '%s ▌%s' "${dim}" "${reset}"
 read -r -s _
-printf "\r${bold}${green}\$${reset} ${white}curl -s .../v1/chat/completions -H 'Authorization: Bearer ${API_KEY}' -d '{...}'${reset}\n\n"
+printf '\r%s%s$%s %scurl -s .../v1/chat/completions -H '\''Authorization: Bearer %s'\'' -d '\''{...}'\''%s\n\n' "${bold}" "${green}" "${reset}" "${white}" "${API_KEY}" "${reset}"
 
 curl -sf -X POST "${GATEWAY_URL}/v1/chat/completions" \
      -H "Content-Type: application/json" \
@@ -286,16 +286,16 @@ section "Step 7 — Streaming (SSE)"
 pause_comment "Add stream:true — tokens arrive in real time"
 
 echo
-printf "${dim}# Same endpoint, stream:true → server-sent events${reset}\n"
-printf "${bold}${green}\$${reset} "
+printf '%s# Same endpoint, stream:true → server-sent events%s\n' "${dim}" "${reset}"
+printf '%s%s$%s ' "${bold}" "${green}" "${reset}"
 typewrite "curl -sN http://localhost:${GATEWAY_PORT}/v1/chat/completions \\" 0.03
-printf "\n"
+printf '\n'
 typewrite "  -H 'Authorization: Bearer ${API_KEY}' \\" 0.03
-printf "\n"
+printf '\n'
 typewrite "  -d '{\"model\":\"smollm2\",\"messages\":[{\"role\":\"user\",\"content\":\"Count 1 to 5\"}],\"stream\":true}'" 0.03
-printf "${dim} ▌${reset}"
+printf '%s ▌%s' "${dim}" "${reset}"
 read -r -s _
-printf "\r${bold}${green}\$${reset} ${white}curl -sN .../v1/chat/completions -d '{...stream:true...}'${reset}\n\n"
+printf '\r%s%s$%s %scurl -sN .../v1/chat/completions -d '\''{...stream:true...}'\''%s\n\n' "${bold}" "${green}" "${reset}" "${white}" "${reset}"
 
 curl -sfN -X POST "${GATEWAY_URL}/v1/chat/completions" \
      -H "Content-Type: application/json" \
@@ -327,15 +327,15 @@ section "Step 8 — Advanced config: load balancing & fallbacks"
 pause_comment "Restart the gateway with the advanced config"
 
 echo
-printf "${dim}# config-advanced.yaml${reset}\n"
+printf '%s# config-advanced.yaml%s\n' "${dim}" "${reset}"
 cat "${SCRIPT_DIR}/config-advanced.yaml"
 echo
 
-printf "${bold}${green}\$${reset} "
+printf '%s%s$%s ' "${bold}" "${green}" "${reset}"
 typewrite "docker model gateway --config demos/gateway/config-advanced.yaml" 0.035
-printf "${dim} ▌${reset}"
+printf '%s ▌%s' "${dim}" "${reset}"
 read -r -s _
-printf "\r${bold}${green}\$${reset} ${white}docker model gateway --config demos/gateway/config-advanced.yaml${reset}\n"
+printf '\r%s%s$%s %sdocker model gateway --config demos/gateway/config-advanced.yaml%s\n' "${bold}" "${green}" "${reset}" "${white}" "${reset}"
 
 stop_gateway
 launch_gateway "${SCRIPT_DIR}/config-advanced.yaml"
@@ -351,12 +351,12 @@ section "Step 9 — Round-robin load balancing"
 pause_comment "'fast-model' has 2 backends — watch them alternate across 4 requests"
 
 echo
-printf "${dim}# 4 requests to 'fast-model' → round-robins across smollm2 + qwen3${reset}\n"
-printf "${bold}${green}\$${reset} "
+printf '%s# 4 requests to '\''fast-model'\'' → round-robins across smollm2 + qwen3%s\n' "${dim}" "${reset}"
+printf '%s%s$%s ' "${bold}" "${green}" "${reset}"
 typewrite "for i in 1 2 3 4; do curl -s .../v1/chat/completions -d '{\"model\":\"fast-model\",...}'; done" 0.03
-printf "${dim} ▌${reset}"
+printf '%s ▌%s' "${dim}" "${reset}"
 read -r -s _
-printf "\r${bold}${green}\$${reset} ${white}for i in 1 2 3 4; do curl -s .../v1/chat/completions ...; done${reset}\n\n"
+printf '\r%s%s$%s %sfor i in 1 2 3 4; do curl -s .../v1/chat/completions ...; done%s\n\n' "${bold}" "${green}" "${reset}" "${white}" "${reset}"
 
 for i in 1 2 3 4; do
     resp=$(curl -sf -X POST "${GATEWAY_URL}/v1/chat/completions" \
@@ -385,18 +385,18 @@ section "Step 10 — Embeddings (nomic-embed-text)"
 pause_comment "Dedicated embedding model behind its own alias"
 
 echo
-printf "${dim}# POST /v1/embeddings — two sentences, then compute cosine similarity${reset}\n"
-printf "${bold}${green}\$${reset} "
+printf '%s# POST /v1/embeddings — two sentences, then compute cosine similarity%s\n' "${dim}" "${reset}"
+printf '%s%s$%s ' "${bold}" "${green}" "${reset}"
 typewrite "curl -s -X POST http://localhost:${GATEWAY_PORT}/v1/embeddings \\" 0.03
-printf "\n"
+printf '\n'
 typewrite "  -H 'Content-Type: application/json' \\" 0.03
-printf "\n"
+printf '\n'
 typewrite "  -H 'Authorization: Bearer ${API_KEY}' \\" 0.03
-printf "\n"
+printf '\n'
 typewrite "  -d '{\"model\":\"embeddings\",\"input\":[\"The quick brown fox\",\"A fast auburn canine\"]}'" 0.03
-printf "${dim} ▌${reset}"
+printf '%s ▌%s' "${dim}" "${reset}"
 read -r -s _
-printf "\r${bold}${green}\$${reset} ${white}curl -s -X POST .../v1/embeddings -d '{...}'${reset}\n\n"
+printf '\r%s%s$%s %scurl -s -X POST .../v1/embeddings -d '\''{...}'\''%s\n\n' "${bold}" "${green}" "${reset}" "${white}" "${reset}"
 
 curl -sf -X POST "${GATEWAY_URL}/v1/embeddings" \
      -H "Content-Type: application/json" \
@@ -426,7 +426,7 @@ section "Step 11 — OpenAI Python SDK compatibility"
 pause_comment "Any app already using the openai library works with zero code changes"
 
 echo
-printf "${dim}# python demo — just swap base_url to point at the gateway${reset}\n"
+printf '%s# python demo — just swap base_url to point at the gateway%s\n' "${dim}" "${reset}"
 cat <<'PYSHOW'
   from openai import OpenAI
 
@@ -443,11 +443,11 @@ cat <<'PYSHOW'
   print(resp.choices[0].message.content)
 PYSHOW
 
-printf "${bold}${green}\$${reset} "
+printf '%s%s$%s ' "${bold}" "${green}" "${reset}"
 typewrite "python3 demo.py" 0.05
-printf "${dim} ▌${reset}"
+printf '%s ▌%s' "${dim}" "${reset}"
 read -r -s _
-printf "\r${bold}${green}\$${reset} ${white}python3 demo.py${reset}\n\n"
+printf '\r%s%s$%s %spython3 demo.py%s\n\n' "${bold}" "${green}" "${reset}" "${white}" "${reset}"
 
 if python3 -c "import openai" 2>/dev/null; then
     python3 - <<'PYEOF'
@@ -471,7 +471,7 @@ PYEOF
     echo
     ok "OpenAI SDK works against the gateway — no code changes required"
 else
-    printf "${yellow}  (skipped — openai package not installed: pip install openai)${reset}\n"
+    printf '%s  (skipped — openai package not installed: pip install openai)%s\n' "${yellow}" "${reset}"
     ok "OpenAI SDK step skipped — install openai to run it"
 fi
 
@@ -482,7 +482,7 @@ fi
 section "Demo complete"
 
 echo
-printf "${bold}  What we showed:${reset}\n"
+printf '%s  What we showed:%s\n' "${bold}" "${reset}"
 info "YAML-driven config — models, auth, retries, fallbacks"
 info "/health  /v1/models  /v1/chat/completions  /v1/embeddings"
 info "Bearer-token auth  (accept ✓  reject 401 ✓)"