Requests - an Applied Taskfile Examples¶

Open the working directory in terminal (I suggest you to use ./working_dir)

Remember we've fetched some example datasets from the internet in chapter 06?
Let's do it once again. Create a taskfile: task --init. Add tasks:

  download-dataset:
    desc: download a dataset
    cmds:
      - wget https://eforexcel.com/wp/wp-content/uploads/2017/07/10000-Sales-Records.zip

  extract-dataset:
    desc: extract dataset
    deps: download-dataset
    cmds:
      - unzip 10000-Sales-Records.zip

Note that we add a dependency to extract-dataset so when we call this task
it first executes the download-dataset task. Call the extract task:
task extract-dataset

See what happened: first the download-dataset task is executed and only then
the extract-dataset runs. Nice! Now we have an example dataset to query.

This randomly-generated dataset mimics global sales data. Open
the .csv file to see its content format.

Say we need a task that will print out sales of particular product in particular
region of the world. Let's use a taskfile variables: one to set the region,
one to set the product. Add to the vars block of the taskfile:

vars:
  GREETING: Hello, World!
  REGION: Asia
  PRODUCT: Cereal

Add a task that will use these variables to query our dataset using grep:

  query-with-global-vars:
      desc: query a dataset with the variables set globally above
      cmds:
        - cat "10000 Sales Records.csv" | grep "{{.REGION}}" | grep {{.PRODUCT}}

Fine. Now we can make a task that will accept an additional CLI argument
to focus our request. It will use the same variables for region and product,
but it will take an additional argument as well. Note the multi-line syntax:

  query-with-cli-args:
      desc: query a dataset with the variables set globally above
      cmds:
      - |-
        cat "10000 Sales Records.csv" \
        | grep "{{.REGION}}" | grep {{.PRODUCT}} \
        | grep {{.CLI_ARGS}}

Try to call it with a country name as an additional argument, for instance:
task query-with-cli-args -- Kazakhstan

Without a CLI argument it will throw an error, because grep need one argument.

Now let's make another task with local variables overriding global ones:

  query-with-local-vars:
      desc: query a dataset with the variables set globally above
      cmds:
        - cat "10000 Sales Records.csv" | grep "{{.REGION}}" | grep {{.PRODUCT}}
      vars:
        REGION: Europe
        PRODUCT: Meat

Try this task task query-with-local-vars and see data on meat sales in Europe.

Let's make a task that will save our query results into a file, and the name
of this file will be passed as a CLI argumet:

  query-save-to-file:
      desc: query a dataset with the variables set globally above
      cmds:
      - |-
        cat "10000 Sales Records.csv" \
        | grep "{{.REGION}}" | grep {{.PRODUCT}} \
        > {{.CLI_ARGS}}
      vars:
        REGION: Europe
        PRODUCT: Meat

Call this task with an output file name as a CLI argument, for instance:
task query-save-to-file -- euro-meat.csv

Now you can open the output file and make sure that it contains the result
of our query.

That's it!¶

Thank you for attending this tutorial.
Now you know how to use Taskfile. Feel free to apply this knowledge.
Hope Taskfile will appear a useful tool for you and this tutorial helped you
to learn its features and feel its human-friendly approach to task automation.