## Sandstorm Dev Notes -- Part 1

Published 2017-11-17

I like [Sandstorm](https://sandstorm.io) so much that I'm finally developing an app for it. It'll use
[PostGraphQL](https://github.com/postgraphql/postgraphql) to move all of the
business logic into PostgreSQL, and React, Redux, and Apollo to handle
the UI and data reading/manipulation. I'll be documenting the weird issues
I've run into when setting this up, since there aren't a ton of docs on
this particular combo of services.

## PostgreSQL

### `initdb`

Due to how grains have random UID/GID assigned to them for security purposes,
and because `/etc/passwd` and `/etc/group` are not available when running `launcher.sh`,
`initdb` will fail because it wants to look up the current UID in `/etc/passwd`
for security reasons. You can get around this by using
[`nss_wrapper`](https://cwrap.org/nss_wrapper.html):

```
export PGDATA=/var/lib/postgres

echo "postgres:x:$(id -u):$(id -g):PostgreSQL user:/var/lib/postgres:/bin/sh" > /var/passwd
echo "postgres:x:$(id -g):" > /var/group

if [ ! -d $PGDATA ]; then
  LD_PRELOAD=/usr/lib/libnss_wrapper.so NSS_WRAPPER_PASSWD=/var/passwd NSS_WRAPPER_GROUP=/var/group /usr/lib/postgresql/10/bin/initdb
fi
```

### `localhost`

Since you don't have `/etc`. you also don't have `/etc/hosts`, which is where
the hostname `localhost` is defined. Use `127.0.0.1` everywhere (your app,
PostgreSQL config) instead.

## NodeJS

### `HOME`

Some Node modules want your `HOME` directory:

```
/usr/lib/node_modules/npm/node_modules/update-notifier/node_modules/xdg-basedir/index.js:5
const home = os.homedir();
                ^

Error: ENOENT: no such file or directory, uv_os_homedir
```

`export HOME=/var` at the top of `launcher.sh` will fix it.

## Apollo Client, and all XHR for that matter

You'll want to [send cookies from the grain frame](https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/withCredentials)
along with your request, otherwise XHR won't work. In an Apollo client for
GraphQL requests, that looks like this (bonus `Authentication` header
setting for PostGraphQL):

``` js
import { ApolloClient } from 'apollo-client';
import { createHttpLink } from 'apollo-link-http';
import { InMemoryCache } from 'apollo-cache-inmemory';
import { setContext } from 'apollo-link-context';

const httpLink = createHttpLink({ uri: '/graphql' });
const authLink = setContext((_, { headers }) => {
  const { jwtToken } = place.where.jwt.token.stored;

  const newHeaders = {};
  if (jwtToken) {
    newHeaders.authorization = `Bearer ${jwtToken}`;
  }

  return {
    headers: {
      ...headers,
      ...newHeaders,
    },
    credentials: 'include', // gets XHR working with Sandstorm
  };
});

export default new ApolloClient({
  link: authLink.concat(httpLink),
  cache: new InMemoryCache(),
});
```