Display constraints for configuration parameters

Author: ngaumont

CHANGELOG.md

@@ -5,6 +5,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- `cb config-param list-supported` now returns `min_value`, `max_value`, and
+  `enum` constraints for each parameters, if applicable.
 
 ## [3.6.0] - 2024-07-26
 ### Added

spec/cb/config_param_spec.cr

@@ -76,6 +76,9 @@ Spectator.describe ConfigurationParameterGet do
         "parameters": [
           {
             "component": "postgres",
+            "enum": [],
+            "min_value": "100",
+            "max_value": "2000",
             "name": "postgres:max_connections",
             "parameter_name": "max_connections",
             "requires_restart": false,
@@ -104,9 +107,21 @@ Spectator.describe ConfigurationParameterListSupported do
         Factory.configuration_parameter(value: nil),
         Factory.configuration_parameter(
           component: "pgbouncer",
-          name: "pgbouncer:default_pool_size",
-          parameter_name: "default_pool_size",
-          value: nil
+          name: "pgbouncer:auth_type",
+          parameter_name: "auth_type",
+          value: nil,
+          min_value: nil,
+          max_value: nil,
+          enum: ["cert", "md5", "trust"]
+        ),
+        Factory.configuration_parameter(
+          component: "pgbouncer",
+          name: "pgbouncer:fake",
+          parameter_name: "fake",
+          value: nil,
+          min_value: nil,
+          max_value: nil,
+          enum: [] of String
         ),
       ]
     }
@@ -115,9 +130,10 @@ Spectator.describe ConfigurationParameterListSupported do
       action.call
 
       expected = <<-EXPECTED
-        Component   Name                Requires Restart
-        postgres    max_connections     no
-        pgbouncer   default_pool_size   no
+        Component   Name              Requires Restart   Constraints
+        postgres    max_connections   no                 min: 100, max: 2000
+        pgbouncer   auth_type         no                 enum: cert, md5, trust
+        pgbouncer   fake              no
       EXPECTED
 
       expect(&.output).to look_like expected
@@ -128,8 +144,8 @@ Spectator.describe ConfigurationParameterListSupported do
       action.call
 
       expected = <<-EXPECTED
-        Component   Name              Requires Restart
-        postgres    max_connections   no
+        Component   Name              Requires Restart   Constraints
+        postgres    max_connections   no                 min: 100, max: 2000
       EXPECTED
 
       expect(&.output).to look_like expected
@@ -179,6 +195,9 @@ Spectator.describe ConfigurationParameterSet do
           "parameters": [
             {
               "component": "postgres",
+              "enum": [],
+              "min_value": "100",
+              "max_value": "2000",
               "name": "postgres:max_connections",
               "parameter_name": "max_connections",
               "requires_restart": false,
@@ -242,6 +261,9 @@ Spectator.describe ConfigurationParameterReset do
           "parameters": [
             {
               "component": "postgres",
+              "enum": [],
+              "min_value": "100",
+              "max_value": "2000",
               "name": "postgres:max_connections",
               "parameter_name": "max_connections",
               "requires_restart": false,

spec/support/factory.cr

@@ -109,6 +109,9 @@ module Factory
       parameter_name:   "max_connections",
       requires_restart: false,
       value:            "100",
+      enum:             [] of String,
+      min_value:        "100",
+      max_value:        "2000",
     }.merge(params)
 
     CB::Model::ConfigurationParameter.new **params

src/cb/config_param.cr

@@ -93,11 +93,19 @@ module CB
             add "Component"
             add "Name"
             add "Requires Restart"
+            add "Constraints"
           end
 
           header unless no_header
 
-          rows parameters.map { |p| [p.component, p.parameter_name, p.requires_restart ? "yes" : "no"] }
+          rows parameters.map { |p|
+            constraints = [] of String
+            constraints << "enum: #{p.enum.join(", ")}" if p.enum.size > 0
+            constraints << "min: #{p.min_value}" if p.min_value && p.min_value != ""
+            constraints << "max: #{p.max_value}" if p.max_value && p.max_value != ""
+
+            [p.component, p.parameter_name, p.requires_restart ? "yes" : "no", constraints.join(", ")]
+          }
         end
 
         output << table.render << '\n'
@@ -106,6 +114,9 @@ module CB
           "parameters": parameters.map do |p|
             {
               "component":       p.component,
+              "enum":            p.enum,
+              "min_value":       p.min_value,
+              "max_value":       p.max_value,
               "name":            p.name,
               "parameter_name":  p.parameter_name,
               "require_restart": p.requires_restart,

src/models/config_param.cr

@@ -1,11 +1,13 @@
 module CB::Model
   jrecord ConfigurationParameter,
     component : String? = nil,
+    enum : Array(String) = [] of String,
+    min_value : String? = nil,
+    max_value : String? = nil,
     name : String = "",
     parameter_name : String? = nil,
     requires_restart : Bool = false,
     value : String? = nil do
-    @[JSON::Field(key: "parameter_name", emit_null: false)]
     def to_s(io : IO)
       io << name.colorize.t_name << '=' << value
     end