Template Variables

DAG files support Go text/template expressions, expanded at run time.

Available variables

Variable	Example value	Description
{ .Today }	2026-04-05	Current date (YYYY-MM-DD)
{ .Now }	2026-04-05T08:30:00Z	Current time (RFC3339)
{ .Params.name }	sales	Parameter value (from defaults or -p overrides)
{ .Env.KEY }	localhost	DAG-level environment variable
{ .Matrix.key }	lm	Matrix parameter (in matrix-expanded steps)

Usage examples

In environment variables:

env:
  REPORT_DATE: "{{ .Today }}"
  LOG_FILE: "logs/run_{{ .Now }}.log"

In step arguments:

- id: extract
  script: etl/extract.R
  args: ["--dept", "{{ .Params.department }}", "--date", "{{ .Today }}"]

In step fields:

- id: fit
  script: models/fit.R
  args: ["--algo", "{{ .Matrix.algo }}"]
  matrix:
    algo: [lm, glm, gam]

Template syntax

daggle uses Go’s text/template package. A few useful patterns:

# Conditional default
env:
  OUTPUT: '{{ if .Params.output }}{{ .Params.output }}{{ else }}results.csv{{ end }}'

Template expressions are expanded before YAML parsing, so they work in any string field.