Error: Failed to launch the browser process!

[ldesousa]

Describe the bug
mmdc fails with the error message: "Error: Failed to launch the browser process!"

To Reproduce

$ mmdc -i PROV.mm -o PROV.png

Error: Failed to launch the browser process!
[0816/165930.731221:FATAL:zygote_host_impl_linux.cc(117)] No usable sandbox! Update your kernel or see https://chromium.googlesource.com/chromium/src/+/main/docs/linux/suid_sandbox_development.md for more information on developing with the SUID sandbox. If you want to live dangerously and need an immediate workaround, you can try using --no-sandbox.
#0 0x58e9b2b224e2 base::debug::CollectStackTrace()
#1 0x58e9b2a93ab3 base::debug::StackTrace::StackTrace()
#2 0x58e9b2a90cf7 logging::LogMessage::~LogMessage()
#3 0x58e9b05a80a2 content::ZygoteHostImpl::Init()
#4 0x58e9b25dc8af content::ContentMainRunnerImpl::Initialize()
#5 0x58e9b25d9f6b content::RunContentProcess()
#6 0x58e9b25da4fe content::ContentMain()
#7 0x58e9b263c3c6 headless::(anonymous namespace)::RunContentMain()
#8 0x58e9b263c068 headless::HeadlessShellMain()
#9 0x58e9aeb251e3 ChromeMain
#10 0x714505e2a1ca (/usr/lib/x86_64-linux-gnu/libc.so.6+0x2a1c9)
#11 0x714505e2a28b __libc_start_main
#12 0x58e9aeb2502a _start



TROUBLESHOOTING: https://github.com/puppeteer/puppeteer/blob/main/docs/troubleshooting.md

    at onClose (file:///usr/local/lib/node_modules/@mermaid-js/mermaid-cli/node_modules/puppeteer-core/lib/esm/puppeteer/node/BrowserRunner.js:269:20)
    at Interface.<anonymous> (file:///usr/local/lib/node_modules/@mermaid-js/mermaid-cli/node_modules/puppeteer-core/lib/esm/puppeteer/node/BrowserRunner.js:257:24)
    at Interface.emit (node:events:529:35)
    at Interface.close (node:internal/readline/interface:534:10)
    at Socket.onend (node:internal/readline/interface:260:10)
    at Socket.emit (node:events:529:35)
    at endReadableNT (node:internal/streams/readable:1400:12)
    at process.processTicksAndRejections (node:internal/process/task_queues:82:21)

Expected behavior
Expected mmdc to generate an image and exit without error messages.

Desktop (please complete the following information):

• OS: Ubuntu 24.04
• Browser Brave, Firefox
• Version Version 1.68.141 Chromium: 127.0.6533.120 (Official Build) (64-bit), 129.0 (64-bit)

[aloisklink]

Are you running Ubuntu 24.04 and mmdc in a docker/podman container?

If so, you'd either need to add the --cap-add=SYS_ADMIN (not recommended!) to your container, or run puppeteer with the --no-sandbox arg (which is dangerous, but should be mostly safe, as long as there is nothing else in the container that you care about).

You can do this by creating a puppeteerConfig.json file with the contents:

{
  "args": ["--no-sandbox"]
}

Then running mmdc with mmdc --puppeteerConfigFile path/to/my/puppeteerConfig.json -i PROV.mm -o PROV.png.

As an example, you can see how the official minlag/mermaid-cli docker image does this with:

• Dockerfile
• puppeteer-config.json

There's also some alternative steps which are recommended by the Puppeteer team at https://pptr.dev/troubleshooting#setting-up-chrome-linux-sandbox, but I haven't tested them yet.

[ldesousa]

Are you running Ubuntu 24.04 and mmdc in a docker/podman container?

No. This issue does not concern Docker.

[aloisklink]

I recently updated to Ubuntu 24.04 and encountered the same issue!

It looks like Ubuntu 24.04 contains some AppArmor 4 rules that block Puppeteer's sandbox from working properly: puppeteer/puppeteer#12818 (comment)

The easiest thing to do is probably just to prepend all calls to @mermaid-js/mermaid-cli with aa-exec --profile=chrome (see aa-exec).

E.g., if you normally use npx @mermaid-js/mermaid-cli, instead use aa-exec --profile=chrome npx @mermaid-js/mermaid-cli.

Other options would be to:

• Create a new profile in /etc/apparmor.d for Puppeteer.
• Create a puppeteer-config.json file that contains {"executablePath": "/path/to/a/browser/that/already/has/an/entry/in/apparmor.d/e.g./chrome/or/firefox"} and passing it to mermaid-cli
• Or, you could always disable the sandbox completely using the instructions in https://github.com/mermaid-js/mermaid-cli/blob/340561040b6b0621a486e3fc96723139e5718268/docs/linux-sandbox-issue.md, but that has some security implications, so you shouldn't do this unless you trust all the mermaid diagrams you're running mermaid-cli on.