@ -26,7 +26,9 @@ to write lists and dictionaries in YAML.
There's another small quirk to YAML. All YAML files (regardless of their association with Ansible or not) can optionally
begin with ``---`` and end with ``...``. This is part of the YAML format and indicates the start and end of a document.
All members of a list are lines beginning at the same indentation level starting with a ``"- "`` (a dash and a space)::
All members of a list are lines beginning at the same indentation level starting with a ``"- "`` (a dash and a space):
..code:: yaml
---
# A list of tasty fruits
@ -36,7 +38,9 @@ All members of a list are lines beginning at the same indentation level starting
- Mango
...
A dictionary is represented in a simple ``key: value`` form (the colon must be followed by a space)::
A dictionary is represented in a simple ``key: value`` form (the colon must be followed by a space):
..code:: yaml
# An employee record
martin:
@ -44,7 +48,9 @@ A dictionary is represented in a simple ``key: value`` form (the colon must be f
job: Developer
skill: Elite
More complicated data structures are possible, such as lists of dictionaries, dictionaries whose values are lists or a mix of both::
More complicated data structures are possible, such as lists of dictionaries, dictionaries whose values are lists or a mix of both:
..code:: yaml
# Employee records
- martin:
@ -62,7 +68,9 @@ More complicated data structures are possible, such as lists of dictionaries, di
- fortran
- erlang
Dictionaries and lists can also be represented in an abbreviated form if you really want to::
Dictionaries and lists can also be represented in an abbreviated form if you really want to:
..code:: yaml
---
martin: {name: Martin D'vloper, job: Developer, skill: Elite}
@ -72,7 +80,9 @@ These are called "Flow collections".
.._truthiness:
Ansible doesn't really use these too much, but you can also specify a :ref:`boolean value <playbooks_variables>` (true/false) in several forms::
Ansible doesn't really use these too much, but you can also specify a :ref:`boolean value <playbooks_variables>` (true/false) in several forms:
..code:: yaml
create_key: true
needs_agent: false
@ -85,7 +95,9 @@ Use lowercase 'true' or 'false' for boolean values in dictionaries if you want t
Values can span multiple lines using ``|`` or ``>``. Spanning multiple lines using a "Literal Block Scalar" ``|`` will include the newlines and any trailing spaces.
Using a "Folded Block Scalar" ``>`` will fold newlines to spaces; it's used to make what would otherwise be a very long line easier to read and edit.
In either case the indentation will be ignored.
Examples are::
Examples are:
..code:: yaml
include_newlines: |
exactly as you see
@ -97,7 +109,9 @@ Examples are::
single line of text
despite appearances
While in the above ``>`` example all newlines are folded into spaces, there are two ways to enforce a newline to be kept::
While in the above ``>`` example all newlines are folded into spaces, there are two ways to enforce a newline to be kept:
..code:: yaml
fold_some_newlines: >
a
@ -108,12 +122,16 @@ While in the above ``>`` example all newlines are folded into spaces, there are
e
f
Alternatively, it can be enforced by including newline ``\n`` characters::
Alternatively, it can be enforced by including newline ``\n`` characters:
..code:: yaml
fold_same_newlines: "a b\nc d\n e\nf\n"
Let's combine what we learned so far in an arbitrary YAML example.
This really has nothing to do with Ansible, but will give you a feel for the format::
This really has nothing to do with Ansible, but will give you a feel for the format:
..code:: yaml
---
# An employee record
@ -144,17 +162,23 @@ While you can put just about anything into an unquoted scalar, there are some ex
A colon followed by a space (or newline) ``": "`` is an indicator for a mapping.
A space followed by the pound sign ``" #"`` starts a comment.
Because of this, the following is going to result in a YAML syntax error::
Because of this, the following is going to result in a YAML syntax error:
..code:: text
foo: somebody said I should put a colon here: so I did
windows_drive: c:
...but this will work::
...but this will work:
..code:: yaml
windows_path: c:\windows
You will want to quote hash values using colons followed by a space or the end of the line::
You will want to quote hash values using colons followed by a space or the end of the line:
..code:: yaml
foo: 'somebody said I should put a colon here: so I did'
@ -162,14 +186,18 @@ You will want to quote hash values using colons followed by a space or the end o
...and then the colon will be preserved.
Alternatively, you can use double quotes::
Alternatively, you can use double quotes:
..code:: yaml
foo: "somebody said I should put a colon here: so I did"
windows_drive: "c:"
The difference between single quotes and double quotes is that in double quotes
you can use escapes::
you can use escapes:
..code:: yaml
foo: "a \t TAB and a \n NEWLINE"
@ -183,17 +211,23 @@ The following is invalid YAML:
Further, Ansible uses "{{ var }}" for variables. If a value after a colon starts
with a "{", YAML will think it is a dictionary, so you must quote it, like so::
with a "{", YAML will think it is a dictionary, so you must quote it, like so:
..code:: yaml
foo: "{{ variable }}"
If your value starts with a quote the entire value must be quoted, not just part of it. Here are some additional examples of how to properly quote things::
If your value starts with a quote the entire value must be quoted, not just part of it. Here are some additional examples of how to properly quote things:
shade34321
3 years ago
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