env does not run : may be using vars ?

[patatetom]

hi,
I try for the first time task and I can't get it to do what I want.
here is the configuration file I use :

version: '3'

env:

  ROOTFS: /tmp/rootfs

tasks:

  default:
    cmds:
      - task --list
    silent: true

  test:
    desc: this is a test
    env:
      PATCH: ./patch.tar.gz
    cmds:
      - tar xvzf $PATCH
    sources:
      - $PATCH
    generates:
      - $ROOTFS/myfile
    method: timestamp

cmds runs correctly but sources (and generates) is not taken into account and the task is executed again when it is restarted.
the .task folder is not created whatever the method used.

I tried vars but can't use it afterwards : I always get an error when I run task.

the patch being repeated several times (cmds, sources, etc...) and being able to change in the future, I wish to use a substitute.

thanks for your help, regards, lacsaP.

[andreynering]

Hi @patatetom,

Use vars and interpolation instead of env:

version: '3'

vars:
  ROOTFS: /tmp/rootfs

tasks:
  default:
    cmds:
      - task --list
    silent: true

  test:
    desc: this is a test
    vars:
      PATCH: ./patch.tar.gz
    cmds:
      - tar xvzf {{.ROOTFS}}
    sources:
      - '{{.PATCH}}'
    generates:
      - '{{.ROOTFS}}/myfile'
    method: checksum

[patatetom]

thanks for the quick answer @andreynering.

it works using vars as specified, but only when the checksum method is used.
if I set method to timestamp, the archive is systematically decompressed even if I use the hard file names (eg. without using vars).

here are the three cases : the first one works as expected but not the next two (if I understood the idea of timestamp) :

• vars and checksum is OK :

# Taskfile1.OK.yml
version: '3'
vars:
  ROOTFS: ./work/rootfs
tasks:
  default:
    cmds:
      - task --list
    silent: true
  test:
    desc: this is a test
    vars:
      PATCH: ./patch.tar.gz
    cmds:
      - tar xvzf {{.PATCH}}
    sources:
      - '{{.PATCH}}'
    generates:
      - '{{.ROOTFS}}/myfile'
    method: checksum

$ rm -rf .task/; rm -rf ./work/; task -t Taskfile1.OK.yml test; task -t Taskfile1.OK.yml test
task: [test] tar xvzf ./patch.tar.gz
./work/
./work/rootfs/
./work/rootfs/myfile
task: Task "test" is up to date

• vars and timestamp is KO :

# Taskfile2.KO.yml
version: '3'
vars:
  ROOTFS: ./work/rootfs
tasks:
  default:
    cmds:
      - task --list
    silent: true
  test:
    desc: this is a test
    vars:
      PATCH: ./patch.tar.gz
    cmds:
      - tar xvzf {{.PATCH}}
    sources:
      - '{{.PATCH}}'
    generates:
      - '{{.ROOTFS}}/myfile'
    method: timestamp

$ rm -rf .task/; rm -rf ./work/; task -t Taskfile2.KO.yml test; task -t Taskfile2.KO.yml test
task: [test] tar xvzf ./patch.tar.gz
./work/
./work/rootfs/
./work/rootfs/myfile
task: [test] tar xvzf ./patch.tar.gz
./work/
./work/rootfs/
./work/rootfs/myfile

• just timestamp is KO :

# Taskfile3.KO.yml
version: '3'
tasks:
  default:
    cmds:
      - task --list
    silent: true
  test:
    desc: this is a test
    cmds:
      - tar xvzf ./patch.tar.gz
    sources:
      - ./patch.tar.gz
    generates:
      - ./work/rootfs/myfile
    method: timestamp

$ rm -rf .task/; rm -rf ./work/; task -t Taskfile3.KO.yml test; task -t Taskfile3.KO.yml test
task: [test] tar xvzf ./patch.tar.gz
./work/
./work/rootfs/
./work/rootfs/myfile
task: [test] tar xvzf ./patch.tar.gz
./work/
./work/rootfs/
./work/rootfs/myfile

regards, lacsaP.

[andreynering]

Hi @patatetom,

I didn't see anything wrong if your Taskfile.

The problem may be on how the timestamp mode works: it compares the "updated" date of both files (sources and generates) and run the task if the source is greater. My guess is that tar is keeping the timestamp of the compressed files, instead of resetting them in the moment you decompress them.

Because of this exact type of edge case, checksum was made the default mode and is recommended when possible.

[patatetom]

hi @andreynering,
that's right.
the archive, created after the folders/files it contains, naturally has a later date than the latter and task considers that the task should be executed.
and indeed, by touching the date of ./work/rootfs/myfile, task considers that there is no need to execute the task.
I didn't think of timestamp in this way, i.e. as a delta between sources and generates.
thank you for these clarifications and Merry Christmas.
regards, lacsaP.