Validate first

Always run check before render. It validates template + data without rendering anything.

Basic usage

lakreet-swarm check --template template.ectemplate --data data.csv

Success output

OK
  template:  template.ectemplate
  controls:  2 (Source Text, Opacity)
  data:      data.csv
  rows:      5 valid

Exit code: 0

Error output

Found 3 problem(s) in data.csv:
- Line 3, column "Opacity": "abc" is not a number.
- Line 5, column "Source Text": column "Source Text" is required.
- Line 7, column "Logo": file not found: /assets/missing.png

Exit code: 3 (DATA_INVALID)

What gets validated

Check	Example error
Column matches control	Column "Foo" is not a control of the template
Slider = number	"abc" is not a number
Checkbox = boolean	"yes" is not a boolean (accepts true/false/yes/no/1/0/ya/tidak)
Media file exists	file not found: /path/to/missing.png
Required columns present	column "Source Text" is required
Row column count matches header	expected 2 columns, found 3

Exit codes for scripting

Code	Constant	Meaning
0	OK	All valid
3	DATA_INVALID	Validation failed

lakreet-swarm check --template t.ectemplate --data d.csv
if [ $? -eq 3 ]; then
  echo "Fix data before rendering"
  exit 1
fi

With column mapping

Mapping in lakreet.config.json is applied during check:

lakreet-swarm check --template t.ectemplate --data d.csv --config lakreet.config.json

Dry-run render

Alternative: render --dry-run does the same validation but exits 0 on success:

lakreet-swarm render --template t.ectemplate --data d.csv --dry-run
# 5 row(s) valid. Dry run: nothing rendered.

In CI pipelines

# .github/workflows/ci.yml
- name: Validate data
  run: lakreet-swarm check --template ${{ env.TEMPLATE }} --data ${{ env.DATA }}

Fails fast, no render cost, clear error messages.

Next steps

• Prepare a CSV — avoid common validation errors
• Map columns — fix header mismatches
• Troubleshoot — all error codes & fixes