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{ config, pkgs, ... }:
with pkgs.lib;
let
cfg = config.services.logstash;
listToConfig = list: "[ " + (concatStringsSep ", " (map exprToConfig list)) + " ]";
hashToConfig = attrs:
let
attrNameToConfigList = name:
[ (exprToConfig name) (exprToConfig (getAttr name attrs)) ];
in
"[ " +
(concatStringsSep ", " (map attrNameToConfigList (attrNames attrs))) +
" ]";
valueToConfig = nvpair: let name = nvpair.name; value = nvpair.value; in
if (isAttrs value) && ((!(value ? __type)) || value.__type == "repeated")
then ''
${name} {
${exprToConfig value}
}
''
else "${name} => ${exprToConfig value}";
repeatedAttrsToConfig = values:
concatStringsSep "\n" (map valueToConfig values);
attrsToConfig = attrs:
let
attrToConfig = name: valueToConfig {
inherit name;
value = (getAttr name attrs);
};
in
concatStringsSep "\n" (map attrToConfig (attrNames attrs));
exprToConfig = expr:
let
isCustomType = expr: (isAttrs expr) && (expr ? __type);
isFloat = expr: (isCustomType expr) && (expr.__type == "float");
isHash = expr: (isCustomType expr) && (expr.__type == "hash");
isRepeatedAttrs = expr: (isCustomType expr) && (expr.__type == "repeated");
in
if builtins.isBool expr then (if expr then "true" else "false") else
if builtins.isString expr then ''"${expr}"'' else
if builtins.isInt expr then toString expr else
if isFloat expr then expr.value else
if isList expr then listToConfig expr else
if isHash expr then hashToConfig expr.value else
if isRepeatedAttrs expr then repeatedAttrsToConfig expr.values
else attrsToConfig expr;
mergeConfigs = configs:
let
op = attrs: newAttrs:
let
isRepeated = newAttrs ? __type && newAttrs.__type == "repeated";
in {
values = attrs.values ++ (if isRepeated then newAttrs.values else
map (name: { inherit name; value = getAttr name newAttrs; })
(attrNames newAttrs));
};
in (foldl op { values = []; } configs) // { __type = "repeated"; };
in
{
###### interface
options = {
services.logstash = {
enable = mkOption {
default = false;
description = ''
Enable logstash.
'';
};
inputConfig = mkOption {
default = {};
description = ''
An attribute set (or an expression generated by mkNameValuePairs)
representing a logstash configuration's input section.
Logstash configs are name-value pairs, where values can be bools,
strings, numbers, arrays, hashes, or other name-value pairs,
and names are strings that can be repeated. Name-value pairs with no
repeats are represented by attr sets. Bools, strings, ints, and
arrays are mapped directly. Name-value pairs with repeats can be
generated by the config.lib.logstash.mkNameValuePairs function, which
takes a list of attrsets and combines them while preserving attribute
name duplicates if they occur. Similarly, there are the mkFloat and
mkHash functions, which take a string representation of a float and an
attrset, respectively.
'';
merge = mergeConfigs;
};
filterConfig = mkOption {
default = {};
description = ''
An attribute set (or an expression generated by mkNameValuePairs)
representing a logstash configuration's filter section.
See inputConfig description for details.
'';
merge = mergeConfigs;
};
outputConfig = mkOption {
default = {};
description = ''
An attribute set (or an expression generated by mkNameValuePairs)
representing a logstash configuration's output section.
See inputConfig description for details.
'';
merge = mergeConfigs;
};
};
};
###### implementation
config = mkMerge [ {
lib.logstash = {
mkFloat = stringRep: { __type = "float"; value = stringRep; };
mkHash = attrs: { __type = "hash"; value = attrs; };
mkNameValuePairs = mergeConfigs;
};
} ( mkIf cfg.enable {
systemd.services.logstash = with pkgs; {
description = "Logstash daemon";
wantedBy = [ "multi-user.target" ];
path = [ jre ];
script = "cd /tmp && exec java -jar ${logstash} agent -f ${writeText "logstash.conf" ''
input {
${exprToConfig cfg.inputConfig}
}
filter {
${exprToConfig cfg.filterConfig}
}
output {
${exprToConfig cfg.outputConfig}
}
''} &> /var/log/logstash.log";
};
})];
}
|