scripts: helper script for running a pr (#6692)

this makes it a little bit easier to test tilt contributions

Signed-off-by: Nick Santos <nicholas.j.santos@gmail.com>

Author: nicks

scripts/run-pr.sh

@@ -0,0 +1,105 @@
+#!/bin/bash
+# run-pr.sh — Build & run a tilt PR in a throwaway container, with the
+# tilt-example-html/0-base project loaded.
+#
+# Usage: scripts/run-pr.sh <pr-number>
+set -euo pipefail
+
+PR_NUMBER="${1:?Usage: $0 <pr-number>}"
+
+# ---------- resolve PR via gh -----------------------------------------------
+echo "==> Looking up PR #${PR_NUMBER}..."
+PR_JSON=$(gh pr view "$PR_NUMBER" --repo tilt-dev/tilt --json title,headRefName,headRepository,headRepositoryOwner)
+PR_TITLE=$(echo "$PR_JSON" | jq -r .title)
+PR_BRANCH=$(echo "$PR_JSON" | jq -r .headRefName)
+PR_OWNER=$(echo "$PR_JSON" | jq -r .headRepositoryOwner.login)
+PR_REPO=$(echo "$PR_JSON" | jq -r .headRepository.name)
+CLONE_URL="https://github.com/${PR_OWNER}/${PR_REPO}.git"
+
+echo "    Title:  ${PR_TITLE}"
+echo "    Branch: ${PR_OWNER}:${PR_BRANCH}"
+echo "    Repo:   ${CLONE_URL}"
+
+IMAGE_NAME="tilt-pr-${PR_NUMBER}"
+CONTAINER_NAME="tilt-pr-${PR_NUMBER}-test"
+PORT=10350
+
+cleanup() {
+    echo ""
+    echo "==> Cleaning up..."
+    docker rm -f "$CONTAINER_NAME" 2>/dev/null || true
+}
+trap cleanup EXIT
+
+# ---------- check kubeconfig -----------------------------------------------
+KUBE_CONTEXT=$(kubectl config current-context)
+if [[ "$KUBE_CONTEXT" != *"docker-desktop"* ]]; then
+    echo "Error: kubeconfig context is ${KUBE_CONTEXT}" >&2
+    echo "       This script only supports local clusters running in Docker Desktop." >&2
+    exit 1
+fi
+
+K8S_SERVER=$(kubectl config view --minify -o jsonpath='{.clusters[0].cluster.server}')
+if [ -z "$K8S_SERVER" ]; then
+    echo "Error: could not determine k8s server from kubeconfig." >&2
+    exit 1
+fi
+
+K8S_HOST=$(echo "$K8S_SERVER" | sed -E 's|https?://([^:]+):.*|\1|')
+K8S_PORT=$(echo "$K8S_SERVER" | sed -E 's|https?://[^:]+:([0-9]+).*|\1|')
+
+if [[ "$K8S_HOST" != "127.0.0.1" && "$K8S_HOST" != "localhost" ]]; then
+    echo "Error: kubeconfig cluster server points to ${K8S_SERVER}" >&2
+    echo "       Expected a cluster at localhost. This script only supports local clusters." >&2
+    exit 1
+fi
+
+echo "==> Detected k8s API at ${K8S_HOST}:${K8S_PORT}"
+
+# ---------- build -----------------------------------------------------------
+docker rm -f "$CONTAINER_NAME" 2>/dev/null || true
+
+echo "==> Building tilt from PR #${PR_NUMBER} (this may take a few minutes)..."
+
+docker build -t "$IMAGE_NAME" - <<DOCKERFILE
+# --- Stage 1: build web assets with Node ---
+FROM node:20 AS web
+RUN git clone ${CLONE_URL} /tilt
+WORKDIR /tilt
+RUN git checkout ${PR_BRANCH}
+WORKDIR /tilt/web
+RUN corepack enable && yarn install --immutable && yarn build
+
+# --- Stage 2: build tilt binary with Go ---
+FROM golang:1.25
+RUN apt-get update && apt-get install -y socat && rm -rf /var/lib/apt/lists/*
+RUN git clone ${CLONE_URL} /tilt
+WORKDIR /tilt
+RUN git checkout ${PR_BRANCH}
+# Overlay the freshly-built web assets into the embed directory
+COPY --from=web /tilt/web/build/ pkg/assets/build/
+RUN go install -mod vendor ./cmd/tilt/...
+
+# Clone the example project that tilt will run against
+RUN git clone https://github.com/tilt-dev/tilt-example-html.git /tilt-example-html
+
+WORKDIR /tilt-example-html/0-base
+DOCKERFILE
+
+# ---------- run --------------------------------------------------------------
+echo "==> Starting tilt (web UI at http://localhost:${PORT})..."
+
+# Open the browser after tilt has a moment to start
+(sleep 5 && open "http://localhost:${PORT}") &
+
+# Inside the container:
+#  - socat forwards 127.0.0.1:<k8s-port> → host.docker.internal:<k8s-port>
+#    so the kubeconfig's localhost reference reaches the host's k8s API.
+#  - tilt runs against the example project in the foreground.
+docker run -it --rm \
+    --name "$CONTAINER_NAME" \
+    -p "${PORT}:${PORT}" \
+    -v /var/run/docker.sock:/var/run/docker.sock \
+    -v "${HOME}/.kube:/root/.kube:ro" \
+    "$IMAGE_NAME" \
+    bash -c "socat TCP-LISTEN:${K8S_PORT},fork,reuseaddr,bind=127.0.0.1 TCP:host.docker.internal:${K8S_PORT} & exec tilt up --host 0.0.0.0 --web-mode=prod"