GitHub to Postgres - Data Extraction and Loading Instructions

This page provides you with instructions on how to extract data from GitHub and load it into PostgreSQL. (If this manual process sounds onerous, check out Stitch, which can do all the heavy lifting for you in just a few clicks.)

What is GitHub?

GitHub is a hosting service for computer code and other resources managed by the Git version control and source code management system. It provides collaboration features such as bug tracking, feature requests, task management, and wikis for hosted projects.

What is PostgreSQL?

PostgreSQL, known by most simply as Postgres, is a hugely popular object-relational database management system (ORDBMS). It labels itself as "the world's most advanced open source database," and for good reason. The platform, despite being available for free via an open source license, offers enterprise-grade features including a strong emphasis on extensibility and standards compliance.

It runs on all major operating systems, including Linux, Unix, and Windows. It is fully ACID-compliant, has full support for foreign keys, joins, views, triggers, and stored procedures (in multiple languages). Postgres is often the best tool for the job as a back-end database for web systems and software tools, and cloud-based deployments are offered by most major cloud vendors. Its syntax also forms the basis for querying Amazon Redshift, which makes migration between the two systems relatively painless and makes Postgres a good "first step" for developers who may later expand into Redshift's data warehouse platform.

Getting data out of GitHub

GitHub has a REST API that you can use to get information about projects, repositories, pull requests, and just about every other kind of data GitHub stores. For example, to get information about an issue, you would issue the call GET /repos/:owner/:repo/issues/:number.

Sample GitHub data

Here's an example of the kind of response you might see with a query like the one above.

{
  "id": 1,
  "node_id": "MDU6SXNzdWUx",
  "url": "https://api.github.com/repos/octocat/Hello-World/issues/1347",
  "repository_url": "https://api.github.com/repos/octocat/Hello-World",
  "labels_url": "https://api.github.com/repos/octocat/Hello-World/issues/1347/labels{/name}",
  "comments_url": "https://api.github.com/repos/octocat/Hello-World/issues/1347/comments",
  "events_url": "https://api.github.com/repos/octocat/Hello-World/issues/1347/events",
  "html_url": "https://github.com/octocat/Hello-World/issues/1347",
  "number": 1347,
  "state": "open",
  "title": "Found a bug",
  "body": "I'm having a problem with this.",
  "user": {
    "login": "octocat",
    "id": 1,
    "node_id": "MDQ6VXNlcjE=",
    "avatar_url": "https://github.com/images/error/octocat_happy.gif",
    "gravatar_id": "",
    "url": "https://api.github.com/users/octocat",
    "html_url": "https://github.com/octocat",
    "followers_url": "https://api.github.com/users/octocat/followers",
    "following_url": "https://api.github.com/users/octocat/following{/other_user}",
    "gists_url": "https://api.github.com/users/octocat/gists{/gist_id}",
    "starred_url": "https://api.github.com/users/octocat/starred{/owner}{/repo}",
    "subscriptions_url": "https://api.github.com/users/octocat/subscriptions",
    "organizations_url": "https://api.github.com/users/octocat/orgs",
    "repos_url": "https://api.github.com/users/octocat/repos",
    "events_url": "https://api.github.com/users/octocat/events{/privacy}",
    "received_events_url": "https://api.github.com/users/octocat/received_events",
    "type": "User",
    "site_admin": false
  },
  "labels": [
    {
      "id": 208045946,
      "node_id": "MDU6TGFiZWwyMDgwNDU5NDY=",
      "url": "https://api.github.com/repos/octocat/Hello-World/labels/bug",
      "name": "bug",
      "description": "Something isn't working",
      "color": "f29513",
      "default": true
    }
  ],
  "assignee": {
    "login": "octocat",
    "id": 1,
    "node_id": "MDQ6VXNlcjE=",
    "avatar_url": "https://github.com/images/error/octocat_happy.gif",
    "gravatar_id": "",
    "url": "https://api.github.com/users/octocat",
    "html_url": "https://github.com/octocat",
    "followers_url": "https://api.github.com/users/octocat/followers",
    "following_url": "https://api.github.com/users/octocat/following{/other_user}",
    "gists_url": "https://api.github.com/users/octocat/gists{/gist_id}",
    "starred_url": "https://api.github.com/users/octocat/starred{/owner}{/repo}",
    "subscriptions_url": "https://api.github.com/users/octocat/subscriptions",
    "organizations_url": "https://api.github.com/users/octocat/orgs",
    "repos_url": "https://api.github.com/users/octocat/repos",
    "events_url": "https://api.github.com/users/octocat/events{/privacy}",
    "received_events_url": "https://api.github.com/users/octocat/received_events",
    "type": "User",
    "site_admin": false
  },
  "assignees": [
    {
      "login": "octocat",
      "id": 1,
      "node_id": "MDQ6VXNlcjE=",
      "avatar_url": "https://github.com/images/error/octocat_happy.gif",
      "gravatar_id": "",
      "url": "https://api.github.com/users/octocat",
      "html_url": "https://github.com/octocat",
      "followers_url": "https://api.github.com/users/octocat/followers",
      "following_url": "https://api.github.com/users/octocat/following{/other_user}",
      "gists_url": "https://api.github.com/users/octocat/gists{/gist_id}",
      "starred_url": "https://api.github.com/users/octocat/starred{/owner}{/repo}",
      "subscriptions_url": "https://api.github.com/users/octocat/subscriptions",
      "organizations_url": "https://api.github.com/users/octocat/orgs",
      "repos_url": "https://api.github.com/users/octocat/repos",
      "events_url": "https://api.github.com/users/octocat/events{/privacy}",
      "received_events_url": "https://api.github.com/users/octocat/received_events",
      "type": "User",
      "site_admin": false
    }
  ],
  "milestone": {
    "url": "https://api.github.com/repos/octocat/Hello-World/milestones/1",
    "html_url": "https://github.com/octocat/Hello-World/milestones/v1.0",
    "labels_url": "https://api.github.com/repos/octocat/Hello-World/milestones/1/labels",
    "id": 1002604,
    "node_id": "MDk6TWlsZXN0b25lMTAwMjYwNA==",
    "number": 1,
    "state": "open",
    "title": "v1.0",
    "description": "Tracking milestone for version 1.0",
    "creator": {
      "login": "octocat",
      "id": 1,
      "node_id": "MDQ6VXNlcjE=",
      "avatar_url": "https://github.com/images/error/octocat_happy.gif",
      "gravatar_id": "",
      "url": "https://api.github.com/users/octocat",
      "html_url": "https://github.com/octocat",
      "followers_url": "https://api.github.com/users/octocat/followers",
      "following_url": "https://api.github.com/users/octocat/following{/other_user}",
      "gists_url": "https://api.github.com/users/octocat/gists{/gist_id}",
      "starred_url": "https://api.github.com/users/octocat/starred{/owner}{/repo}",
      "subscriptions_url": "https://api.github.com/users/octocat/subscriptions",
      "organizations_url": "https://api.github.com/users/octocat/orgs",
      "repos_url": "https://api.github.com/users/octocat/repos",
      "events_url": "https://api.github.com/users/octocat/events{/privacy}",
      "received_events_url": "https://api.github.com/users/octocat/received_events",
      "type": "User",
      "site_admin": false
    },
    "open_issues": 4,
    "closed_issues": 8,
    "created_at": "2015-04-10T20:09:31Z",
    "updated_at": "2018-03-03T18:58:10Z",
    "closed_at": "2017-02-12T13:22:01Z",
    "due_on": "2016-10-09T23:39:01Z"
  },
  "locked": true,
  "active_lock_reason": "too heated",
  "comments": 0,
  "pull_request": {
    "url": "https://api.github.com/repos/octocat/Hello-World/pulls/1347",
    "html_url": "https://github.com/octocat/Hello-World/pull/1347",
    "diff_url": "https://github.com/octocat/Hello-World/pull/1347.diff",
    "patch_url": "https://github.com/octocat/Hello-World/pull/1347.patch"
  },
  "closed_at": null,
  "created_at": "2015-04-22T13:33:48Z",
  "updated_at": "2015-04-22T13:33:48Z",
  "closed_by": {
    "login": "octocat",
    "id": 1,
    "node_id": "MDQ6VXNlcjE=",
    "avatar_url": "https://github.com/images/error/octocat_happy.gif",
    "gravatar_id": "",
    "url": "https://api.github.com/users/octocat",
    "html_url": "https://github.com/octocat",
    "followers_url": "https://api.github.com/users/octocat/followers",
    "following_url": "https://api.github.com/users/octocat/following{/other_user}",
    "gists_url": "https://api.github.com/users/octocat/gists{/gist_id}",
    "starred_url": "https://api.github.com/users/octocat/starred{/owner}{/repo}",
    "subscriptions_url": "https://api.github.com/users/octocat/subscriptions",
    "organizations_url": "https://api.github.com/users/octocat/orgs",
    "repos_url": "https://api.github.com/users/octocat/repos",
    "events_url": "https://api.github.com/users/octocat/events{/privacy}",
    "received_events_url": "https://api.github.com/users/octocat/received_events",
    "type": "User",
    "site_admin": false
  }
}

Whew!

Loading data into Postgres

Once you have identified all of the columns you will want to insert, you can use the CREATE TABLE statement in Postgres to create a table that can receive all of this data. Then, Postgres offers a number of methods for loading in data, and the best method varies depending on the quantity of data you have and the regularity with which you plan to load it.

For simple, day-to-day data insertion, running INSERT queries against the database directly are the standard SQL method for getting data added. Documentation on INSERT queries and their bretheren can be found in the Postgres documentation here.

For bulk insertions of data, which you will likely want to conduct if you have a high volume of data to load, other tools exist as well. This is where the COPY command becomes quite useful, as it allows you to load large sets of data into Postgres without needing to run a series of INSERT statements. Documentation can be found here.

The Postgres documentation also provides a helpful overall guide for conducting fast data inserts, populating your database, and avoiding common pitfalls in the process. You can find it here.

Keeping GitHub data up to date

Now what? You've built a script that pulls data from the GitHub API and loads it into your data warehouse, but what happens tomorrow when you have new data?

The key is to build your script in such a way that it can identify incremental updates to your data. Thankfully, many of GitHub's API results include fields like created_at that allow you to identify records that are new since your last update (or since the newest record you've copied). Once you've take new data into account, you can set your script up as a cron job or continuous loop to keep pulling down new data as it appears.

Other data warehouse options

PostgreSQL is great, but sometimes you need to optimize for different things when you're choosing a data warehouse. Some folks choose to go with Amazon Redshift, Google BigQuery, Snowflake, or Microsoft Azure Synapse Analytics, which are RDBMSes that use similar SQL syntax, or Panoply, which works with Redshift instances. Others choose a data lake, like Amazon S3 or Delta Lake on Databricks. If you're interested in seeing the relevant steps for loading data into one of these platforms, check out To Redshift, To BigQuery, To Snowflake, To Panoply, To Azure Synapse Analytics, To S3, and To Delta Lake.

Easier and faster alternatives

If all this sounds a bit overwhelming, don’t be alarmed. If you have all the skills necessary to go through this process, chances are building and maintaining a script like this isn’t a very high-leverage use of your time.

Thankfully, products like Stitch were built to move data from GitHub to PostgreSQL automatically. With just a few clicks, Stitch starts extracting your GitHub data, structuring it in a way that's optimized for analysis, and inserting that data into your PostgreSQL data warehouse.