diff options
author | Naïm Favier <n@monade.li> | 2022-12-02 13:39:47 +0100 |
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committer | Naïm Favier <n@monade.li> | 2022-12-02 14:15:24 +0100 |
commit | e8927c46b8693b1d0b1d6e12cd602c6647217d3a (patch) | |
tree | f742957d53cbcbdee782de8966dadde425d21001 | |
parent | 3dc19ce82d5a435ff63a2d8771aaf4a8243f0c0f (diff) |
nixos/doc: document `mkOrder` and friends
Add a section on ordering option definitions. Also mention `mkDefault` in the section on `mkOverride`. Clarify the code a bit by renaming `defaultPriority` to `defaultOverridePriority` and introducing `defaultOrderPriority`.
-rw-r--r-- | lib/modules.nix | 19 | ||||
-rw-r--r-- | nixos/doc/manual/development/option-def.section.md | 26 | ||||
-rw-r--r-- | nixos/doc/manual/from_md/development/option-def.section.xml | 40 | ||||
-rw-r--r-- | nixos/modules/virtualisation/qemu-vm.nix | 2 |
4 files changed, 67 insertions, 20 deletions
diff --git a/lib/modules.nix b/lib/modules.nix index 204a2cc1ac12a..f5e69ad4bcf56 100644 --- a/lib/modules.nix +++ b/lib/modules.nix @@ -833,7 +833,7 @@ rec { filterOverrides' = defs: let - getPrio = def: if def.value._type or "" == "override" then def.value.priority else defaultPriority; + getPrio = def: if def.value._type or "" == "override" then def.value.priority else defaultOverridePriority; highestPrio = foldl' (prio: def: min (getPrio def) prio) 9999 defs; strip = def: if def.value._type or "" == "override" then def // { value = def.value.content; } else def; in { @@ -842,7 +842,7 @@ rec { }; /* Sort a list of properties. The sort priority of a property is - 1000 by default, but can be overridden by wrapping the property + defaultOrderPriority by default, but can be overridden by wrapping the property using mkOrder. */ sortProperties = defs: let @@ -851,7 +851,7 @@ rec { then def // { value = def.value.content; inherit (def.value) priority; } else def; defs' = map strip defs; - compare = a: b: (a.priority or 1000) < (b.priority or 1000); + compare = a: b: (a.priority or defaultOrderPriority) < (b.priority or defaultOrderPriority); in sort compare defs'; # This calls substSubModules, whose entire purpose is only to ensure that @@ -887,10 +887,13 @@ rec { mkOptionDefault = mkOverride 1500; # priority of option defaults mkDefault = mkOverride 1000; # used in config sections of non-user modules to set a default + defaultOverridePriority = 100; mkImageMediaOverride = mkOverride 60; # image media profiles can be derived by inclusion into host config, hence needing to override host config, but do allow user to mkForce mkForce = mkOverride 50; mkVMOverride = mkOverride 10; # used by ‘nixos-rebuild build-vm’ + defaultPriority = lib.warnIf (lib.isInOldestRelease 2305) "lib.modules.defaultPriority is deprecated, please use lib.modules.defaultOverridePriority instead." defaultOverridePriority; + mkFixStrictness = lib.warn "lib.mkFixStrictness has no effect and will be removed. It returns its argument unmodified, so you can just remove any calls." id; mkOrder = priority: content: @@ -899,11 +902,9 @@ rec { }; mkBefore = mkOrder 500; + defaultOrderPriority = 1000; mkAfter = mkOrder 1500; - # The default priority for things that don't have a priority specified. - defaultPriority = 100; - # Convenient property used to transfer all definitions and their # properties from one option to another. This property is useful for # renaming options, and also for including properties from another module @@ -930,10 +931,10 @@ rec { # Similar to mkAliasAndWrapDefinitions but copies over the priority from the # option as well. # - # If a priority is not set, it assumes a priority of defaultPriority. + # If a priority is not set, it assumes a priority of defaultOverridePriority. mkAliasAndWrapDefsWithPriority = wrap: option: let - prio = option.highestPrio or defaultPriority; + prio = option.highestPrio or defaultOverridePriority; defsWithPrio = map (mkOverride prio) option.definitions; in mkAliasIfDef option (wrap (mkMerge defsWithPrio)); @@ -1115,7 +1116,7 @@ rec { # to definitions. mkDerivedConfig = opt: f: mkOverride - (opt.highestPrio or defaultPriority) + (opt.highestPrio or defaultOverridePriority) (f opt.value); doRename = { from, to, visible, warn, use, withPriority ? true }: diff --git a/nixos/doc/manual/development/option-def.section.md b/nixos/doc/manual/development/option-def.section.md index 91b24cd4a3a16..22cf38873cf07 100644 --- a/nixos/doc/manual/development/option-def.section.md +++ b/nixos/doc/manual/development/option-def.section.md @@ -59,17 +59,35 @@ config = { ## Setting Priorities {#sec-option-definitions-setting-priorities .unnumbered} A module can override the definitions of an option in other modules by -setting a *priority*. All option definitions that do not have the lowest +setting an *override priority*. All option definitions that do not have the lowest priority value are discarded. By default, option definitions have -priority 1000. You can specify an explicit priority by using -`mkOverride`, e.g. +priority 100 and option defaults have priority 1500. +You can specify an explicit priority by using `mkOverride`, e.g. ```nix services.openssh.enable = mkOverride 10 false; ``` This definition causes all other definitions with priorities above 10 to -be discarded. The function `mkForce` is equal to `mkOverride 50`. +be discarded. The function `mkForce` is equal to `mkOverride 50`, and +`mkDefault` is equal to `mkOverride 1000`. + +## Ordering Definitions {#sec-option-definitions-ordering .unnumbered} + +It is also possible to influence the order in which the definitions for an option are +merged by setting an *order priority* with `mkOrder`. The default order priority is 1000. +The functions `mkBefore` and `mkAfter` are equal to `mkOrder 500` and `mkOrder 1500`, respectively. +As an example, + +```nix +hardware.firmware = mkBefore [ myFirmware ]; +``` + +This definition ensures that `myFirmware` comes before other unordered +definitions in the final list value of `hardware.firmware`. + +Note that this is different from [override priorities](#sec-option-definitions-setting-priorities): +setting an order does not affect whether the definition is included or not. ## Merging Configurations {#sec-option-definitions-merging .unnumbered} diff --git a/nixos/doc/manual/from_md/development/option-def.section.xml b/nixos/doc/manual/from_md/development/option-def.section.xml index 8c9ef181affd2..3c1a979e70f33 100644 --- a/nixos/doc/manual/from_md/development/option-def.section.xml +++ b/nixos/doc/manual/from_md/development/option-def.section.xml @@ -66,11 +66,11 @@ config = { <title>Setting Priorities</title> <para> A module can override the definitions of an option in other - modules by setting a <emphasis>priority</emphasis>. All option - definitions that do not have the lowest priority value are - discarded. By default, option definitions have priority 1000. You - can specify an explicit priority by using - <literal>mkOverride</literal>, e.g. + modules by setting an <emphasis>override priority</emphasis>. All + option definitions that do not have the lowest priority value are + discarded. By default, option definitions have priority 100 and + option defaults have priority 1500. You can specify an explicit + priority by using <literal>mkOverride</literal>, e.g. </para> <programlisting language="bash"> services.openssh.enable = mkOverride 10 false; @@ -78,7 +78,35 @@ services.openssh.enable = mkOverride 10 false; <para> This definition causes all other definitions with priorities above 10 to be discarded. The function <literal>mkForce</literal> is - equal to <literal>mkOverride 50</literal>. + equal to <literal>mkOverride 50</literal>, and + <literal>mkDefault</literal> is equal to + <literal>mkOverride 1000</literal>. + </para> + </section> + <section xml:id="sec-option-definitions-ordering"> + <title>Ordering Definitions</title> + <para> + It is also possible to influence the order in which the + definitions for an option are merged by setting an <emphasis>order + priority</emphasis> with <literal>mkOrder</literal>. The default + order priority is 1000. The functions <literal>mkBefore</literal> + and <literal>mkAfter</literal> are equal to + <literal>mkOrder 500</literal> and + <literal>mkOrder 1500</literal>, respectively. As an example, + </para> + <programlisting language="bash"> +hardware.firmware = mkBefore [ myFirmware ]; +</programlisting> + <para> + This definition ensures that <literal>myFirmware</literal> comes + before other unordered definitions in the final list value of + <literal>hardware.firmware</literal>. + </para> + <para> + Note that this is different from + <link linkend="sec-option-definitions-setting-priorities">override + priorities</link>: setting an order does not affect whether the + definition is included or not. </para> </section> <section xml:id="sec-option-definitions-merging"> diff --git a/nixos/modules/virtualisation/qemu-vm.nix b/nixos/modules/virtualisation/qemu-vm.nix index 9af7e07ccfbab..eae898a08a69c 100644 --- a/nixos/modules/virtualisation/qemu-vm.nix +++ b/nixos/modules/virtualisation/qemu-vm.nix @@ -806,7 +806,7 @@ in optional ( cfg.writableStore && cfg.useNixStoreImage && - opt.writableStore.highestPrio > lib.modules.defaultPriority) + opt.writableStore.highestPrio > lib.modules.defaultOverridePriority) '' You have enabled ${opt.useNixStoreImage} = true, without setting ${opt.writableStore} = false. |