gatsby-node.js

const path = require("path");
const s3 = require('s3');
const fs = require('fs');
const secrets = require('./secrets.json');
const _ = require('lodash')

exports.createPages = ({ actions, graphql }) => {
  const { createPage } = actions;

  const blogPostTemplate = path.resolve("src/templates/blog-post.js");
  const tagTemplate = path.resolve("src/templates/tags.js");

  return graphql(`
    {
      allMarkdownRemark(
        sort: { order: DESC, fields: [frontmatter___date] }
        limit: 2000
      ) {
        edges {
          node {
            frontmatter {
                date
                path
                title
                tags
                featureimage
            }
          }
        }
      }
    }
  `).then(result => {
    if (result.errors) {
      return Promise.reject(result.errors);
    }

    const posts = result.data.allMarkdownRemark.edges;

    // Create post detail pages
    posts.forEach(({ node }) => {
      createPage({
        path: node.frontmatter.path,
        component: blogPostTemplate,
      });
    });

    // Tag pages:
    let tags = [];
    // Iterate through each post, putting all found tags into `tags`
    _.each(posts, edge => {
      if (_.get(edge, "node.frontmatter.tags")) {
        tags = tags.concat(edge.node.frontmatter.tags);
      }
    });
    // Eliminate duplicate tags
    tags = _.uniq(tags);

    // Make tag pages
    tags.forEach(tag => {
      createPage({
        path: `/tags/${_.kebabCase(tag)}/`,
        component: tagTemplate,
        context: {
          tag,
        },
      });
    });
  });
};

exports.onPostBuild = (args, pluginOptions) =>
  new Promise(resolve => {
    if (secrets && secrets.s3) {

      // Init S3 client
      const client = s3.createClient({
        s3RetryCount: 6,
        s3RetryDelay: 30,
        s3Options: {
          accessKeyId: secrets.s3.id,
          secretAccessKey: secrets.s3.secret,
          signatureVersion: 'v4',
          region: secrets.s3.region
        },
      });

      // Sync dir
      const params = {
        localDir: "public",
        deleteRemoved: true,
        s3Params: {
          Bucket: secrets.s3.bucket,
          Prefix: secrets.s3.remoteDir,
        },
      };
      const uploader = client.uploadDir(params);

      uploader.on('error', function (err) {
        console.error("unable to sync:", err.stack);
        resolve();
      });
      uploader.on('progress', function () {
        console.log("progress", uploader.progressAmount, uploader.progressTotal);
      });
      uploader.on('end', function () {
        console.log("done uploading");
        resolve();
      });
    }
  });