Tutorials on Automation

Learn about Automation from fellow newline community members!

  • React
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  • JavaScript
  • TypeScript
  • Node.js
  • Deno
  • Rust
  • Python
  • GraphQL
  • React
  • Angular
  • Vue
  • Svelte
  • NextJS
  • Redux
  • Apollo
  • Storybook
  • D3
  • Testing Library
  • JavaScript
  • TypeScript
  • Node.js
  • Deno
  • Rust
  • Python
  • GraphQL

Release Management with ASP.Net Core and GitHub Actions

In this article, we will learn how to set up automated release creation for an ASP.Net Core project with GitHub ActionsRelease management can be a complicated beast at the best of times, and is notoriously hard to get right. Previously, shell scripts and batch files used to be the most common tools used for automation, and countless hours were spent trying to get them working as expected. This has changed in recent times, with platforms such as GitHub Actions providing a much simpler way of automating tasks and managing releases. In the last article , we have seen how GitHub Actions can be used to set up a pipeline for Continuous Integration (CI). In the following sections, we will build on that, and add a workflow that publishes release artifacts when new code is merged to the main branch. For the purposes of this tutorial, we will use a simple .NET Core console application. This can be created via the following command using the .NET CLI which is installed along with the SDK. We will use the GitHub repository that we created in the previous article, which already contains a GitHub Actions CI workflow that builds and runs unit tests on pushes to main and pull request branches. A tag is a label that can be applied to any commit in your repository for later identification. Tags are typically used to mark commits for releases. You can create a tag using the following commands in your terminal/command line. Tag names can be any arbitrary string, but are usually version numbers like v1.0.0 or v.1.1.2-beta5. When a tag has been published, it will appear in the 'Tags' section in your repository. You can then use the created tag to create a GitHub release - each release has a title, short description and attachments such as release notes, source code and built artifacts. In the next step, we will learn how to build our project and associate the built app code artifacts with the just-created release. Let us now create a release.yml file in the .github/workflows directory alongside the ci.yml workflow we have defined previously. We will use the release published event to trigger our workflow. This means our workflow will get triggered when a new release is published using the mechanism from the previous step. Let us now understand what this workflow does: We can now create a release using the steps described earlier. Let us first tag the last commit in our repo. I'll call the tag v1.0 . The tag will now appear in the 'Tags' section, and we can create a release from it. The release notes can be automatically populated based on the commits since the last tag. Once we hit publish, a release gets created on the 'Releases' page. Note that this only has the source code, and not the built artifacts from the tagged commit. Publishing the release also triggers our new workflow. When the workflow has finished, the built ZIP file and tarball are added to the release assets, and we have successfully released v1.0 of our app! 🎉 In this tutorial, we have learnt how to create and automate tasks around releases for an ASP.Net Core project using GitHub Actions. We built on concepts we learnt in the previous tutorial on CI with GitHub Actions . If you find yourself stuck at any point during the tutorial, you can view all the source code on my GitHub here . More detail on all the events that can be used to trigger GitHub Actions workflows can be found in the GitHub docs .

Thumbnail Image of Tutorial Release Management with ASP.Net Core and GitHub Actions

ffmpeg - Thumbnail and Preview Clip Generation (Part 2)

Disclaimer - If you are unfamiliar with FFmpeg, then please read this blog post before proceeding. When you upload a video to a platform such as Youtube , you can select and add a custom thumbnail image to display within its result item. Amongst the many recommended videos, a professionally-made thumbnail captures the attention of undecided users and improves the chances of your video being played. At a low-level, a thumbnail consists of an image, a title and a duration (placed within a faded black box and fixed to the lower-right corner): To generate a thumbnail from a video with ffmpeg : Let's test the drawtext filter by extracting the thumbnail image from the beginning of the video and writing "Test Text" to the center of this image. This thumbnail image will be a JPEG file. Notice that the drawtext filter accepts the parameters text , fontcolor , fontsize , x and y for configuring it: The parameters are delimited by a colon. To see a full list of drawtext parameters, click here . Now that we've covered the basics, let's add a duration to this thumbnail: Unfortunately, there's no convenient variable like w or tw for accessing the input's duration. Therefore, we must extract the duration from the input's information, which is outputted by the -i option. 2>&1 redirects standard error ( 2 for stderr ) to standard output ( 1 for stdout ). We pipe the information outputted by the -i option directly to grep to search for the line containing the text "Duration" and pipe it to cut to extract the duration (i.e., 00:00:10 for ten seconds) from this line. This duration is stored within a variable DURATION so that it can be injected into the text passed to drawtext . Here, we use two drawtext filters to modify the input media: one for writing the title text "Test Text" and one for writing the duration "00:00:10". The filters are comma delimited. To place the duration within a box, provide the box parameter and set it to 1 to enable it. To set the background color of this box, provide the boxcolor parameter. Note : Alternatively, you could get the video's duration via the ffprobe command. Let's tidy up this thumbnail by substituting the placeholder title with the actual title, uppercasing this title, changing the font to "Open Sans" and moving the duration box to the bottom-right corner. Like the duration, the title must also be extracted from the input media's information. To uppercase every letter in the title, place the ^^ symbol of Bash 4 at the end of the title's variable via parameter expansion ( ${TITLE^^} ). Since Bash is required for the uppercasing, let's place these commands inside of a .sh file beginning with a Bash shebang , which determines how the script will be executed. To find the location of the Bash interpreter for the shebang, run the following command: ( thumbnail.sh ) To specify a font weight for a custom font, reference that font weight's file as the fontfile . Don't forget to replace <username> with your own username! Additionally, several changes were made to the thumbnail box. The box color has a subtle opacity of 0.625. This number (any number between 0 and 1) proceeds the @ in the boxcolor . A border width of 8px provides a bit of spacing between the edges of the box and the text itself. Note : If you run into a bash: Bad Substitution error, update Bash to version 4+ and verify the Bash shebang correctly points to the Bash executable. When you hover over a recommended video's thumbnail, a brief clip appears and plays to give you an idea of what the video's content is. With the ffmpeg command, generating a clip from a video is relatively easy. Just provide a starting timestamp via the -ss option (from the original video, -ss seeks until it reaches this timestamp, which will serve as the point the clip begins at) and an ending timestamp via the -to option (from the original video at which the clip should end). Because video previews on Youtube are three seconds long, let's extract a three second segment starting from the four second mark and ending at the seven second mark. Since the clip lasts for a few seconds, we must re-encode the video (exclude -c copy ) to accurately capture instances when no keyframes exist. To clip a video without re-encoding, ffmpeg must capture a sufficient number of keyframes from the video. Since MP4s are encoded with the H.264 video codec ( h264 (High) is stated under the video's metadata printed by ffmpeg -i <input> ), if we assume that there are 250 frames between any two keyframes ("a GOP size of 250"), then for the ten second Big Buck Bunny video with a frame rate of 30 fps, there is one keyframe each eight to nine seconds. Clipping a video less than nine seconds with -c copy results in no keyframes being captured, and thus, the outputted clip contains no video ( 0 kB of video). Eight Second Clip (with -c copy ): Nine Second Clip (with -c copy ): Note : Alternatively, the -t option can be used in place of the -to option. With the -t option, you must specify the duration rather than the ending timestamp. So instead of 00:00:07 with -to , it would be 00:00:03 with -t for a three second clip. Suppose you want to add your brand's logo, custom-made title graphics or watermark to the thumbnail. To overlay such an image on top of a thumbnail, pass this image as an input file via the i option and apply the overlay filter. Position the image on top of the thumbnail accordingly with the x and y parameters. ( thumbnail.sh ) Passing multiple inputs (in this case, a video and watermark image) requires the -filter_complex option in place of the -vf option. The main_h and overlay_h variables represent the main input's height (from the input video) and the overlay's height (from the input watermark image) respectively. Here, we place the watermark image in the lower-left corner of the thumbnail. The watermark image looks a bit large compared to the other elements on the thumbnail. Let's scale down the watermark image to half its original size by first scaling it down before any of the existing chained filters are executed. ( thumbnail.sh ) To scale the watermark image to half its size, we must explicitly tell the scale filter to only scale this image and not the video. This is done by prepending [1:v] to the scale filter to have the scale filter target our second input -i ./watermark-ex.png . The iw and ih variables will represent the watermark image's width and height respectively. Once the scaling is done, the scaled watermark image is outputted to ovrl , which can be referenced by other filters for consumption as a filter input. Because the overlay filter takes two inputs, an input video and an input image overlay, we prepend the overlay filter with these inputs: [0:v] for the first input -i ./Big_Buck_Bunny_360_10s_30MB.mp4 and ovrl for our scaled watermark image. Imagine having a large repository of videos that needs to be processed and uploaded during continuous integration. Write a Bash script to automate this process.

Thumbnail Image of Tutorial ffmpeg - Thumbnail and Preview Clip Generation (Part 2)