# Question about passing a list to a module **URL:** \ **Category:** Ansible Project\ **Tags:** ubuntu\ **Created:** [February 16, 2013, 8:58pm UTC](https://forum.ansible.com/t/question-about-passing-a-list-to-a-module/12369 "2013-02-16T20:58:23Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Steve1](https://avatars.discourse-cdn.com/v4/letter/s/3da27b/32.png) [@Steve1](https://forum.ansible.com/u/Steve1)\ **Post date:** [February 16, 2013, 8:58pm UTC](https://forum.ansible.com/t/question-about-passing-a-list-to-a-module/12369/1 "2013-02-16T20:58:23Z")
I’d like to enhance the ec2 module to support creating/attaching volumes. Updating it was rather simple, but I am having trouble passing volumes to it, due to the way vars get parsed (i think). In the playbook, I want to do something like > vars: > > - volumes: > - { device: “/dev/sdf”, size: 1 } > - { device: “/dev/sdg”, size: 1 } > - { device: “/dev/sdh”, size: 1, otherattrib: value } > tasks: > - local\_action: ec2 keypair=“test” group=“test” instance\_type=“t1.micro” image=“ami-3d4ff254” wait=true **volumes=$volumes** But that fails with: > File “/home/ubuntu/ansible/lib/ansible/utils/template.py”, line 222, in varReplace > replacement = “,”.join(replacement) > TypeError: sequence item 0: expected string, dict found So I hacked lib/ansible/utils/template.py: > if expand\_lists and isinstance(replacement, (list, tuple)): > if isinstance(replacement, (list)): > parts = > for item in replacement: > if item is dict: > pass > else: > parts.append(item) > replacement = parts. **str** () > else: > replacement = “,”.join(replacement) Which was enough to let me move on… but I still am dealing with a string instead of a list of dictionaries like I was hoping for. So I wound up using ast.literal\_eval. **So my question is, is there a way to pass a variable (which is a list) without it getting converted to a string?** New ec2 module code: ---
**Author:** ![Michael\_DeHaan](https://avatars.discourse-cdn.com/v4/letter/m/c4cdca/32.png) [@Michael\_DeHaan](https://forum.ansible.com/u/Michael_DeHaan)\ **Post date:** [February 16, 2013, 9:13pm UTC](https://forum.ansible.com/t/question-about-passing-a-list-to-a-module/12369/2 "2013-02-16T21:13:13Z")
> I'd like to enhance the ec2 module to support creating/attaching volumes. You may be interested to see the ec2vol module I just pushed today from Lester Wade! > Updating it was rather simple, but I am having trouble passing volumes to > it, due to the way vars get parsed (i think). > > In the playbook, I want to do something like > > >   vars: > >   - volumes: > >     - { device: "/dev/sdf", size: 1 } > >     - { device: "/dev/sdg", size: 1 } > >     - { device: "/dev/sdh", size: 1, otherattrib: value } > >   tasks: > >   - local\_action: ec2 keypair="test" group="test" instance\_type="t1.micro" > > image="ami-3d4ff254" wait=true volumes=$volumes > > But that fails with: > > >   File "/home/ubuntu/ansible/lib/ansible/utils/template.py", line 222, in > > varReplace > >     replacement = ",".join(replacement) > > TypeError: sequence item 0: expected string, dict found Us exposing tracebacks and not errors for humans isn't cool, but it's true it didn't expect a list there. In general you can't do that. What you want is: - location\_action: foo arg=$item   with\_items: $listvar And yes, that will call your module multiple times. You can't pass complex variables to modules -- that's coming super soon now (this weekend) - although even then the module has to be coded to do something with that data. > So I hacked lib/ansible/utils/template.py: > > >         if expand\_lists and isinstance(replacement, (list, tuple)): > >             if isinstance(replacement, (list)): > >                 parts = > >                 for item in replacement: > >                     if item is dict: > >                         pass > >                     else: > >                         parts.append(item) > >                 replacement = parts.\_\_str\_\_() > >             else: > >                 replacement = ",".join(replacement) > > Which was enough to let me move on... but I still am dealing with a string > instead of a list of dictionaries like I was hoping for. So I wound up using > ast.literal\_eval. > > So my question is, is there a way to pass a variable (which is a list) > without it getting converted to a string? with\_items is what you want. ---
**Author:** ![Steve1](https://avatars.discourse-cdn.com/v4/letter/s/3da27b/32.png) [@Steve1](https://forum.ansible.com/u/Steve1)\ **Post date:** [February 16, 2013, 11:05pm UTC](https://forum.ansible.com/t/question-about-passing-a-list-to-a-module/12369/3 "2013-02-16T23:05:06Z")
Of course I started coding right before your merges… that’s life. The ec2\_vol module will work, though not as I had intended. I will now be provisioning the volumes in my setup playbook, instead of my provisioning playbook. To provision, I have different values for instances and volumes based on whether this is dev, staging or prod, but it is basically something like: vars: - instances: - { name: db1, type: db, instance: $instance\_type, image: $image\_type } - { name: db2, type: db, instance: $instance\_type, image: $image\_type } - { name: dbx, type: db, instance: $instance\_type, image: $image\_type } - volumes: - { device: “/dev/sdf”, size: 1 } - { device: “/dev/sdg”, size: 1 } - { device: “/dev/sdh”, size: 1, otherattrib: value } tasks: - local\_action: ec2 … register: instres with\_items: ${instances} - local\_action: wait\_for host=${item.public\_dns\_name} port=22 delay=20 timeout=300 with\_items: ${instres.results[0].instances} So to use ec2\_vol here wouldn’t work since I would need to loop over 2 lists, which I don’t think is possible. - local\_action: ec2\_vol … with\_items: ${instres.results[0].instances} with\_items: ${volumes} won’t work. I was trying not to introduce yet another module. Namespaces/subdirectories will be really nice. Complex variables sounds awesome. Can’t wait to look.