Web UI does not open up inside devcontainer workspace

[mhbdev]

npx workflow inspect runs --web --verbose

┌────────────────────────────────────────────────────────┐
│                                                        │
│               Workflow CLI v4.0.1-beta.6               │
│           Docs at https://useworkflow.dev/             │
│    This is an alpha release - commands might change    │
│                                                        │
└────────────────────────────────────────────────────────┘
[Debug] Inferring env vars, backend: embedded
[Warn] PORT environment variable is not set, using default port 3000
[Debug] Found workflow data directory: /workspace/web/.next/workflow-data
[Debug] Initializing world
[Debug] Resolving web package from: /workspace/web/node_modules/.pnpm/@workflow+cli@4.0.1-beta.6_@aws-sdk+client-sts@3.920.0_@babel+core@7.28.5_@opentelemetr_24c131d3a84ae4725df3d42f71943485/node_modules/@workflow/cli/dist/lib/inspect/web.js
[Debug] Resolved web package: /workspace/web/node_modules/.pnpm/@workflow+web@4.0.1-beta.6_@babel+core@7.28.5_@opentelemetry+api@1.9.0_react-dom@19.2.0_react@19.2.0__react@19.2.0/node_modules/@workflow/web/package.json
[Debug] Using web package at: /workspace/web/node_modules/.pnpm/@workflow+web@4.0.1-beta.6_@babel+core@7.28.5_@opentelemetry+api@1.9.0_react-dom@19.2.0_react@19.2.0__react@19.2.0/node_modules/@workflow/web
[Info] Starting web UI server...
[Debug] Running npx next start -p 3456 in /workspace/web/node_modules/.pnpm/@workflow+web@4.0.1-beta.6_@babel+core@7.28.5_@opentelemetry+api@1.9.0_react-dom@19.2.0_react@19.2.0__react@19.2.0/node_modules/@workflow/web
[Debug] [web-server] ⚠ You are using a non-standard "NODE_ENV" value in your environment. This creates inconsistencies in the project and is strongly advised against. Read more: https://nextjs.org/docs/messages/non-standard-node-env
[Debug] [web-server] ▲ Next.js 15.5.4
[Debug] [web-server] - Local:        http://localhost:3456
   - Network:      http://172.22.0.5:3456

 ✓ Starting...
[Debug] [web-server] ⨯ Failed to load next.config.ts, see more info here https://nextjs.org/docs/messages/next-config-error
[Debug] [web-server] [Error: Cannot find module './src/lib/env'
Require stack:
- /workspace/web/node_modules/.pnpm/@workflow+web@4.0.1-beta.6_@babel+core@7.28.5_@opentelemetry+api@1.9.0_react-dom@19.2.0_react@19.2.0__react@19.2.0/node_modules/@workflow/web/next.config.compiled.js
- /workspace/web/node_modules/.pnpm/next@15.5.4_@babel+core@7.28.5_@opentelemetry+api@1.9.0_react-dom@19.2.0_react@19.2.0__react@19.2.0/node_modules/next/dist/build/next-config-ts/transpile-config.js
- /workspace/web/node_modules/.pnpm/next@15.5.4_@babel+core@7.28.5_@opentelemetry+api@1.9.0_react-dom@19.2.0_react@19.2.0__react@19.2.0/node_modules/next/dist/server/config.js
- /workspace/web/node_modules/.pnpm/next@15.5.4_@babel+core@7.28.5_@opentelemetry+api@1.9.0_react-dom@19.2.0_react@19.2.0__react@19.2.0/node_modules/next/dist/cli/next-test.js
- /workspace/web/node_modules/.pnpm/next@15.5.4_@babel+core@7.28.5_@opentelemetry+api@1.9.0_react-dom@19.2.0_react@19.2.0__react@19.2.0/node_modules/next/dist/bin/next] {
  code: 'MODULE_NOT_FOUND',
  requireStack: [Array]
}
[Debug] Web server exited with code 1
[Error] Server failed to start within 30000ms
[Error] Failed to start web UI server

[mrestrepoj10]

🙋🏿‍♂️ having the same issue

[VaguelySerious]

@mhbdev @mrestrepoj10 It's working fine for me using the VSCode/Cursor dev container plugin:

---

Can you provide a reproducible example? Are you sure your dev container configuration is correct?

Here are my Dockerfile and .devcontainer.json for reference:

# Dockerfile
# Use Node.js LTS version
FROM node:20-slim

# Install pnpm globally with the specific version from package.json
RUN npm install -g pnpm@10.17.1

# Set working directory
WORKDIR /workspace

# Copy package files
COPY package.json pnpm-lock.yaml ./

# Install dependencies
RUN pnpm install --frozen-lockfile

# Copy the rest of the application
COPY . .

# Expose the port that dev server runs on
EXPOSE 3000

# Start the development server
CMD ["pnpm", "dev"]

// .devcontainer.json
{
	"name": "NextJS Workflow App",
	"dockerFile": "Dockerfile",
	"context": ".",
	"appPort": [3000],
	"forwardPorts": [3000],
	"workspaceFolder": "/workspace",
	"remoteUser": "node",
	"postCreateCommand": "pnpm install",
	"customizations": {
		"vscode": {
			"extensions": [
				"esbenp.prettier-vscode",
				"dbaeumer.vscode-eslint",
				"ms-vscode.vscode-typescript-next"
			],
			"settings": {
				"terminal.integrated.defaultProfile.linux": "zsh",
				"editor.formatOnSave": true,
				"editor.defaultFormatter": "esbenp.prettier-vscode",
				"editor.codeActionsOnSave": {
					"source.fixAll.eslint": "explicit"
				}
			}
		}
	}
}

[mhbdev]

@mhbdev @mrestrepoj10 It's working fine for me using the VSCode/Cursor dev container plugin:

---

Can you provide a reproducible example? Are you sure your dev container configuration is correct?

Here are my Dockerfile and .devcontainer.json for reference:

# Dockerfile
# Use Node.js LTS version
FROM node:20-slim

# Install pnpm globally with the specific version from package.json
RUN npm install -g pnpm@10.17.1

# Set working directory
WORKDIR /workspace

# Copy package files
COPY package.json pnpm-lock.yaml ./

# Install dependencies
RUN pnpm install --frozen-lockfile

# Copy the rest of the application
COPY . .

# Expose the port that dev server runs on
EXPOSE 3000

# Start the development server
CMD ["pnpm", "dev"]

// .devcontainer.json
{
	"name": "NextJS Workflow App",
	"dockerFile": "Dockerfile",
	"context": ".",
	"appPort": [3000],
	"forwardPorts": [3000],
	"workspaceFolder": "/workspace",
	"remoteUser": "node",
	"postCreateCommand": "pnpm install",
	"customizations": {
		"vscode": {
			"extensions": [
				"esbenp.prettier-vscode",
				"dbaeumer.vscode-eslint",
				"ms-vscode.vscode-typescript-next"
			],
			"settings": {
				"terminal.integrated.defaultProfile.linux": "zsh",
				"editor.formatOnSave": true,
				"editor.defaultFormatter": "esbenp.prettier-vscode",
				"editor.codeActionsOnSave": {
					"source.fixAll.eslint": "explicit"
				}
			}
		}
	}
}

Thank you I will test it out