Version-Aware JIT Source Provisioning with TTL

Atmos now supports intelligent version-aware JIT (Just-In-Time) source provisioning with automatic re-provisioning on version changes and TTL-based cleanup for stale workdirs.

What Changed

The workdir provisioning system has been enhanced with version tracking and intelligent re-provisioning:

• Version-aware re-provisioning - When a remote source version changes in your configuration, Atmos automatically re-provisions the workdir with the new version
• URI change detection - Changing the source URI triggers re-provisioning to ensure you always have the correct source
• Incremental local sync - Local component changes are synced using per-file checksums, copying only modified files
• TTL-based cleanup - Stale workdirs can be cleaned up automatically based on last-accessed time
• Enhanced metadata - Workdirs now track source_uri, source_version, and last_accessed timestamps

Why This Matters

Previously, if you updated a component's source version in your stack configuration, you had to manually clean the workdir before the change would take effect. Now Atmos handles this automatically:

• Seamless version upgrades - Change version: "0.24.0" to version: "0.25.0" and run terraform plan - Atmos detects the mismatch and re-provisions automatically
• Reduced disk usage - The --expired cleanup option removes workdirs that haven't been accessed within a configurable TTL
• Faster local iteration - Only modified files are synced to workdirs, making local development faster
• Full visibility - The workdir list and workdir show commands now display version and access information

How to Use It

Version-Aware Provisioning

Configure a component with a source version:

components:
  terraform:
    vpc:
      source:
        uri: "github.com/cloudposse/terraform-aws-vpc//src"
        version: "0.25.0"
      provision:
        workdir:
          enabled: true

When you change the version, Atmos automatically re-provisions:

$ atmos terraform plan vpc -s dev
# Output: "Source version changed (0.24.0 → 0.25.0)"
# Workdir is re-provisioned with the new version

TTL-Based Cleanup

Clean workdirs that haven't been accessed in a week:

$ atmos terraform workdir clean --expired --ttl=7d
Cleaning expired workdirs (TTL: 7d)...
  ✓ Removed dev-nginx (last accessed 14 days ago)
  ✓ Removed staging-api (last accessed 10 days ago)
Cleaned 2 expired workdirs

Preview what would be cleaned with dry-run:

$ atmos terraform workdir clean --expired --ttl=7d --dry-run
Dry run: would clean 2 expired workdir(s) (TTL: 7d):
  - dev-nginx (last accessed 14d 2h)
  - staging-api (last accessed 10d 5h)

Enhanced Workdir Information

View detailed workdir information:

$ atmos terraform workdir show vpc --stack dev
✓ Workdir Status

  Name            dev-vpc
  Component       vpc
  Stack           dev
  Source Type     remote
  Source URI      github.com/cloudposse/terraform-aws-vpc//src
  Source Version  0.25.0
  Path            .workdir/terraform/dev-vpc
  Created         2026-01-20 10:00:00 UTC
  Updated         2026-01-22 14:30:00 UTC
  Last Accessed   2026-01-22 14:30:00 UTC

List workdirs with version and access information:

$ atmos terraform workdir list
COMPONENT   STACK   TYPE     VERSION   LAST_ACCESSED        PATH
vpc         dev     remote   0.25.0    2026-01-22 14:30     .workdir/terraform/dev-vpc
my-local    dev     local    -         2026-01-22 10:15     .workdir/terraform/dev-my-local

TTL Format

The --ttl flag supports various duration formats:

• Time units: 30m, 2h, 7d (minutes, hours, days)
• Keywords: hourly, daily, weekly, monthly
• Seconds: 3600 (plain integers are interpreted as seconds)

Get Involved

Have feedback on the version-aware provisioning feature? Open an issue on GitHub or join the discussion in our Slack community.