Clarify examples in include merging and deep merging documentation (#607).

This commit is contained in:
Dan Helfman 2022-10-28 19:33:19 -07:00
parent 89500df429
commit 6aeb74550d
2 changed files with 57 additions and 23 deletions

1
NEWS
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@ -1,5 +1,6 @@
1.7.5.dev0
* #604: Fix traceback when a configuration section is present but lacking any options.
* #607: Clarify examples in include merging and deep merging documentation.
1.7.4
* #596: Fix special file detection erroring when broken symlinks are encountered.

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@ -106,11 +106,60 @@ But if you do want to merge in a YAML key *and* its values, keep reading!
## Include merging
If you need to get even fancier and pull in common configuration options while
potentially overriding individual options, you can perform a YAML merge of
included configuration using the YAML `<<` key. For instance, here's an
example of a main configuration file that pulls in two retention options via
an include and then overrides one of them locally:
If you need to get even fancier and merge in common configuration options, you
can perform a YAML merge of included configuration using the YAML `<<` key.
For instance, here's an example of a main configuration file that pulls in
retention and consistency options via a single include:
```yaml
<<: !include /etc/borgmatic/common.yaml
location:
...
```
This is what `common.yaml` might look like:
```yaml
retention:
keep_hourly: 24
keep_daily: 7
consistency:
checks:
- name: repository
```
Once this include gets merged in, the resulting configuration would have all
of the `location` options from the original configuration file *and* the
`retention` and `consistency` options from the include.
Prior to borgmatic version 1.6.0, when there's a section collision between the
local file and the merged include, the local file's section takes precedence.
So if the `retention` section appears in both the local file and the include
file, the included `retention` is ignored in favor of the local `retention`.
But see below about deep merge in version 1.6.0+.
Note that this `<<` include merging syntax is only for merging in mappings
(configuration options and their values). But if you'd like to include a
single value directly, please see the section above about standard includes.
Additionally, there is a limitation preventing multiple `<<` include merges
per section. So for instance, that means you can do one `<<` merge at the
global level, another `<<` within each configuration section, etc. (This is a
YAML limitation.)
### Deep merge
<span class="minilink minilink-addedin">New in version 1.6.0</span> borgmatic
performs a deep merge of merged include files, meaning that values are merged
at all levels in the two configuration files. This allows you to include
common configuration—up to full borgmatic configuration files—while overriding
only the parts you want to customize.
For instance, here's an example of a main configuration file that pulls in two
retention options via an include and then overrides one of them locally:
```yaml
<<: !include /etc/borgmatic/common.yaml
@ -136,24 +185,8 @@ Once this include gets merged in, the resulting configuration would have a
When there's an option collision between the local file and the merged
include, the local file's option takes precedence.
Note that this `<<` include merging syntax is only for merging in mappings
(configuration options and their values). But if you'd like to include a
single value directly, please see the section above about standard includes.
Additionally, there is a limitation preventing multiple `<<` include merges
per section. So for instance, that means you can do one `<<` merge at the
global level, another `<<` within each configuration section, etc. (This is a
YAML limitation.)
### Deep merge
<span class="minilink minilink-addedin">New in version 1.6.0</span> borgmatic
performs a deep merge of merged include files, meaning that values are merged
at all levels in the two configuration files. Colliding list values are
appended together. This allows you to include common configuration—up to full
borgmatic configuration files—while overriding only the parts you want to
customize.
<span class="minilink minilink-addedin">New in version 1.6.1</span> Colliding
list values are appended together.
## Configuration overrides