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Add logstash module.

Since the logstash config file seemed very similar to a nixexpr, I decided
to map directly from nixexprs to logstash configs. I didn't realize until
too far in that this solution was probably way over-engineered, but it
works.
This commit is contained in:
Shea Levy 2012-07-11 11:22:16 -04:00
parent b7398794ed
commit 3039caf5ad
2 changed files with 153 additions and 0 deletions

View file

@ -83,6 +83,7 @@
./services/hardware/upower.nix
./services/logging/klogd.nix
./services/logging/logrotate.nix
./services/logging/logstash.nix
./services/logging/syslogd.nix
./services/mail/dovecot.nix
./services/mail/dovecot2.nix

View file

@ -0,0 +1,152 @@
{ 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 = name: value:
if (isAttrs value) && ((!(value ? __type)) || value.__type == "repeated")
then ''
${name} {
${exprToConfig value}
}
''
else "${name} => ${exprToConfig value}";
repeatedAttrsToConfig = names: values:
concatStringsSep "\n" (zipListsWith valueToConfig names values);
attrsToConfig = attrs:
let
attrToConfig = name: valueToConfig name (getAttr name attrs);
in
concatStringsSep "\n" (map attrToConfig (attrNames attrs));
exprToConfig = expr:
let
isCustomType = expr: (isAttrs expr) && (expr ? __type);
isFloat = expr: (isCustomType expr) && (expr.__type == "float");
isHash = expr: (isCustomType expr) && (expr.__type == "hash");
isRepeatedAttrs = expr: (isCustomType expr) && (expr.__type == "repeated");
in
if builtins.isBool expr then (if expr then "true" else "false") else
if builtins.isString expr then ''"${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.names expr.values
else attrsToConfig expr;
mergeConfigs = configs:
let
op = attrs: newAttrs:
let
isRepeated = newAttrs ? __type && newAttrs.__type == "repeated";
in {
names = attrs.names ++
(if isRepeated then newAttrs.names else attrNames newAttrs);
values = attrs.values ++
(if isRepeated then newAttrs.values else attrValues newAttrs);
};
in (foldl op { names = []; values = []; } configs) //
{ __type = "repeated"; };
in
{
###### interface
options = {
services.logstash = {
enable = mkOption {
default = false;
description = ''
Enable logstash.
'';
};
inputConfig = mkOption {
default = {};
description = ''
An attr set 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. name-value pairs with repeats
are represented by an attrset with attr "__type" = "repeated" and
attrs "names" and "values" as matching lists pairing name and value.
bools, strings, ints, and arrays are mapped directly. Floats are
represented as an attrset with attr "__type" = "float" and attr value
set to the string representation of the float. Hashes are represented
with attr "__type" = "hash" and attr value set to an attr set
corresponding to the hash.
'';
merge = mergeConfigs;
};
filterConfig = mkOption {
default = {};
description = ''
An attr set representing a logstash configuration's filter section.
See inputConfig description for details.
'';
merge = mergeConfigs;
};
outputConfig = mkOption {
default = {};
description = ''
An attr set representing a logstash configuration's output section.
See inputConfig description for details.
'';
merge = mergeConfigs;
};
};
};
###### implementation
config = mkIf cfg.enable {
# Always log to stdout
services.logstash.outputConfig = { stdout = {}; };
jobs.logstash = with pkgs; {
description = "Logstash daemon";
path = [ jre ];
exec = "java -jar ${logstash} agent -f ${writeText "logstash.conf" ''
input {
${exprToConfig cfg.inputConfig}
}
filter {
${exprToConfig cfg.filterConfig}
}
output {
${exprToConfig cfg.outputConfig}
}
''}";
};
};
}