Use Gatsby dev to proxy dev-server

[jameshadfield]

Closes #158. From #158 (comment):

So, my approach is similar to option 1, which is running both the dev-server and gatsby dev server, but I take advantage of Gatsby's built-in development API proxy (https://www.gatsbyjs.com/docs/api-proxy/).

I made a proof-of-concept in my fork https://github.com/didithilmy/nextstrain.org/tree/use-gatsby-dev. Try to run npm run dev from the root directory.

Unfortunately, it involves Gatsby knowing what paths are NOT supposed to be served by Gatsby, which is located in server.js, outside static-site. In my solution, I moved the auspicePaths into a separate file, which is included by static-site/gatsby-config.js.

[jameshadfield]

Thanks @didithilmy -- this solution looks good and should become the go-to method for development inside this repo. I don't have any issues with moving the paths into a separate file. Tested in both dev & production modes and couldn't find any issues.

@eharkins would you mind taking a look 🙏

[jameshadfield]

We should also update the README through this PR

[eharkins]

I added some updates to the README and static-site/README @jameshadfield. npm run dev worked for me in my existing checkout of the repo.

However, when I created a fresh clone to try and come up with instructions for the README for running a dev server from scratch, I got inconsistent errors when building the site from scratch, so couldn't come up with a complete set of instructions for running a dev server from scatch. Maybe you or @didithilmy can come up with a complete set of instructions for needs to happen before you can run a dev server if you are starting anew and add them here:
https://github.com/nextstrain/nextstrain.org/pull/280/files#diff-b335630551682c19a781afebcf4d07bf978fb1f8ac04c6bf87428ed5106870f5R39
?

[didithilmy]

Can you try running npm run build first?
I don’t think I can push commits to this PR, since the branch isn’t on my fork.

[jameshadfield]

However, when I created a fresh clone to try and come up with instructions for the README for running a dev server from scratch, I got inconsistent errors when building the site from scratch

Good find -- thanks for running this extra check. I think this occurs because npm ci hasn't yet been run from within the static-site directory. Recommending npm run build is smart as that'll both install static-site deps and also build auspice.

[eharkins]

I still get

  TypeError: createProxyMiddleware is not a function
  - gatsby-config.js:79 forEach.path
     /Users/eharkins/nextstrain/test/nextstrain.org/static-site/gatsby-config.js:79:9

after running the following in a new clone of this branch:

npm ci
npm run build
npm run dev

which seems like it should work since it completes the build of the static site (along with installing dependencies) during npm run build without error (the error comes when i run npm run dev). But if this doesn't happen for either of you then probably an issue on my end.

[jameshadfield]

@eharkins this should now be working 🤞 could you re-test please?

[eharkins]

Works now, thanks both!

I updated the README and static-site/README to make it explicit that running npm run build is necessary in both ways of running the server. Feel free to edit my language there.