tools: allow separate component install w/ env var

[rvagg]

Primary use cases are: headers tarball (previously using HEADERS_ONLY)
and OS X installer so it has npm files separate from core node + header
files. This is a component of #5656, a rework of the OS X installer, which now
has a working checkbox to optionally install npm.

• set NODE_INSTALL_NODE_ONLY for core node executable and associated
  extras (dtrace, systemtap, gdbinit, man page).
• set NODE_INSTALL_HEADERS_ONLY for header files as required for
  compiling native addons, previously HEADERS_ONLY, used for creating
  the headers tarball for distribution.
• set NODE_INSTALL_NPM_ONLY to install npm only, including executable
  symlink.

If none of these are set, install everything.

Options are mutually exclusive, run install.py multiple times to install
multiple components.

/cc @nodejs/build @fhemberger

I'm also open to making this a semver-major change because of the change from HEADERS_ONLY to NODE_INSTALL_HEADERS_ONLY although I don't imagine anyone's actually using that in the wild (it's new and also pretty obscure for use outside of the Makefile).

[thefourtheye]

Hmmm, not sure if this is correct. I mean, node_install_headers corresponds to npm_files?

[bnoordhuis]

It should probably be node_install_npm.

[rvagg]

yeah, not sure how that happened, fixing

[rvagg]

I'm also happy to consider that (1) environment variables for this are kind of gross and perhaps we should be using command-line arguments and/or (2) that they should be opt-out rather than opt-in (e.g. set a variable to 0 if you don't want that component installed, or the variable name has "DONT" in it or similar), I just think that the logic involved in that gets more awkward and it's simpler to say that an env var being set is a signal to do something rather than not do something.

This is my proposal as is but I'd like to make sure it smells OK too, so speak up if your nose is twitching.

[bnoordhuis]

Options are mutually exclusive, run install.py multiple times to install multiple components.

Is that intentional or just how it turned out? You can approach it like this:

if os.environ.get('NODE_INSTALL_HEADERS', True): header_files(action)
if os.environ.get('NODE_INSTALL_NODE', True): node_files(action)
if os.environ.get('NODE_INSTALL_NPM', True): npm_files(action)

[rvagg]

os.environ.get('NODE_INSTALL_HEADERS', True) - is that "default to True"? What values of NODE_INSTALL_HEADERS will evaluate to True vs False in this case?

[bnoordhuis]

os.environ.get('NODE_INSTALL_HEADERS', True) - is that "default to True?

Yes.

What values of NODE_INSTALL_HEADERS will evaluate to true vs false in this case?

Empty strings are false, everything else is truthy.

[rvagg]

Empty strings are false, everything else is truthy.

So using that logic, this:

    NODE_INSTALL_HEADERS_ONLY=1 $(PYTHON) tools/install.py install '$(TARNAME)' '/' 

would become:

    NODE_INSTALL_NODE="" NODE_INSTALL_NPM="" $(PYTHON) tools/install.py install '$(TARNAME)' '/' 

?

[thefourtheye]

@rvagg Yes, and I don't like that 😢. Instead of saying, install only headers, we are saying don't install node and npm.

[rvagg]

Another option:

$(PYTHON) tools/install.py install-headers

And:

$(PYTHON) tools/install.py install-headers install-node /path/to/node/
$(PYTHON) tools/install.py install-npm /path/to/npm/

[rvagg]

Or brevity:

$(PYTHON) tools/install.py headers

And:

$(PYTHON) tools/install.py headers node /path/to/node/
$(PYTHON) tools/install.py npm /path/to/npm/

Where the default, everything, is:

$(PYTHON) tools/install.py install

[rvagg]

Although, "uninstall" is a problem in that case. Perhaps:

$(PYTHON) tools/install.py install --include-node --include-npm --include-headers

And an inverse:

$(PYTHON) tools/install.py install --no-include-node --no-include-npm --no-include-headers

but tbh, they all kind of smell

[thefourtheye]

How about

tools/install.py --install node,npm,headers
tools/install.py --uninstall node,npm,headers

[rvagg]

@thefourtheye yeah, that's not bad, but it's a big departure from the existing API which uses fixed arguments:

• argv[1]: 'install' or 'uninstall' (cmd)
• argv[2]: prefix for destination (DESTDIR)
• argv[3]: prefix within destination (PREFIX)

I reckon there's >0 users in the wild that are relying on this script outside of make.

[rvagg]

we could just add --components node,npm,headers that overrides the default of everything and works for both install and uninstall.

[thefourtheye]

we could just add --components node,npm,headers ...

yeah, that SGTM.

[rvagg]

If someone with better Python chops wants to code some of that up for me it'd be appreciated, otherwise I'll muddle through it when I have the time.

[thefourtheye]

@rvagg @bnoordhuis I created #5741. PTAL

[rvagg]

#5741 is now my preferred option, closing in favour of that one but discussion is still open around all of this.