Simple Image Processing

In this example tutorial, we will show you how to use Bacalhau to process images on a Landsat dataset.

Bacalhau has the unique capability of operating at a massive scale in a distributed environment. This is made possible because data is naturally sharded across the IPFS network amongst many providers. We can take advantage of this to process images in parallel.

TD;LR

Processing of images from a dataset using Bacalhau

Prerequisite

To get started, you need to install the Bacalhau client, see more information here

!command -v bacalhau >/dev/null 2>&1 || (export BACALHAU_INSTALL_DIR=.; curl -sL https://get.bacalhau.org/install.sh | bash)
path=!echo $PATH
%env PATH=./:{path[0]}

Running a Bacalhau Job

To submit a workload to Bacalhau, we will use the bacalhau docker run command.

%%bash --out job_id
bacalhau docker run \
  --wait \
  --wait-timeout-secs 100 \
  --id-only \
  -i ipfs://QmeZRGhe4PmjctYVSVHuEiA9oSXnqmYa4kQubSHgWbjv72:/input_images \
  dpokidov/imagemagick:7.1.0-47-ubuntu \
  -- magick mogrify -resize 100x100 -quality 100 -path /outputs '/input_images/*.jpg'

The job has been submitted and Bacalhau has printed out the related job id. We store that in an environment variable so that we can reuse it later on.

%env JOB_ID={job_id}

env: JOB_ID=bf785b4d-dcac-4f4a-9c63-cf9906aa2941

The bacalhau docker run command allows to pass input data volume with a -i ipfs://CID:path argument just like Docker, except the left-hand side of the argument is a content identifier (CID). This results in Bacalhau mounting a data volume inside the container. By default, Bacalhau mounts the input volume at the path /inputs inside the container.

Bacalhau also mounts a data volume to store output data. The bacalhau docker run command creates an output data volume mounted at /outputs. This is a convenient location to store the results of your job.

Checking the State of your Jobs

• Job status: You can check the status of the job using bacalhau list.

%%bash
bacalhau list --id-filter=${JOB_ID} --no-style

 CREATED   ID        JOB                       STATE      VERIFIED  PUBLISHED
 00:26:44  bf785b4d  Docker dpokidov/image...  Completed            ipfs://QmQnern37ueHr...

When it says Published or Completed, that means the job is done, and we can get the results.

• Job information: You can find out more information about your job by using bacalhau describe.

%%bash
bacalhau describe ${JOB_ID}

• Job download: You can download your job results directly by using bacalhau get. Alternatively, you can choose to create a directory to store your results. In the command below, we created a directory and downloaded our job output to be stored in that directory.

%%bash
rm -rf results && mkdir results # Temporary directory to store the results
bacalhau get ${JOB_ID} --output-dir results # Download the results

After the download has finished you should see the following contents in results directory.

Viewing your Job Output

To view the file, run the following command:

%%bash
ls -lah results/outputs

Display the image

To view the images, we will use glob to return all file paths that match a specific pattern.

import glob
from IPython.display import Image, display
for imageName in glob.glob('results/outputs/*.jpg'):
    display(Image(filename=imageName))

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