Use gatsby-source-graphql to enable schema stitching with Github's API, rather than this source plugin.

Source plugin for pulling in Github data (using its GraphQL API) at buildtime for static generation and further GraphQL querying with Gatsby. Check out this repo for an example usage.

npm install gatsby-source-github --save-dev

In your gatsby-config.js:

plugins: [
  {
    resolve: 'gatsby-source-github',
    options: {
      headers: {
        Authorization: `Bearer YOUR_GITHUB_PERSONAL_ACCESS_TOKEN`, // https://help.github.com/articles/creating-a-personal-access-token-for-the-command-line/
      },
      queries: [
        `{
          repository(owner: "nebraskajs", name: "speaker-signup") {
            issues(last: 20, states: OPEN) {
              edges {
                node {
                  id
                  author {
                    avatarUrl
                    login
                    url
                  }
                  bodyHTML
                  title
                  url
                }
              }
            }
          }
        }`,
      ],
    },
  },
];

queries is an array of GraphQL queries. The algorithm to generate Gatsby GraphQL nodes is described below

In general, use the Github API v4 documentation and in particular, the explorer to craft your queries and refer to the the below algorithm for how to query against these results with Gatsby.

Additionally, variables can be used/injected into the queries. Rather than sending a string in the queries array, send an array like so:

[
  `query getViewer($first: Int!) {
    viewer {
      login
      name
      repositories(first:$first) {
        edges {
          node {
            name
          }
        }
      }
    }
  }`,
  { first: 10 },
];

The algorithm is quite simple. It'll descend through the tree/returned structure, and if it finds an edges key will use the parent of that as the node name. For instance, in the above repository example, githubIssue will be the node name, and allGithubIssues will be the way to query against all nodes. In the viewer example the node name will be githubViewer.

All fields in the node that are queried against in the Github GraphQL query are available to be queried with Gatsby. For example, in the repository example above, id, author (and subfields), bodyHTML, etc. are available to be queried against.