0.8.3: resolve #6: "generate conf template"

build.sbt

@@ -1,4 +1,4 @@
-lazy val tscfgVersion = setVersion("0.8.2")
+lazy val tscfgVersion = setVersion("0.8.3")
 
 organization := "com.github.carueda"
 name := "tscfg"

changelog.md

@@ -1,3 +1,7 @@
+2017-09-05 - 0.8.3
+
+- resolve #6: "generate conf template"
+
 2017-07-13
 
 - basic experimentation with static-config

readme.md

@@ -24,6 +24,7 @@ The generated code only depends on the Typesafe Config library.
   - [list type](#list-type)
   - [object type](#object-type)
   - [optional object or list](#optional-object-or-list)
+- [configuration template](#configuration-template)
 - [FAQ](#faq)
 - [tests](#tests)
 
@@ -189,6 +190,9 @@ Options (default):
   --j7                  generate code for java <= 7      (8)
   --scala               generate scala code              (java)
   --java                generate java code               (the default)
+  --tpl <filename>      generate config template         (not generated)
+  --tpl.ind <string>    template indentation string      ("  ")
+  --tpl.cp <string>     prefix for template comments     ("##")
 Output is written to $destDir/$className.ext
 ```
 
@@ -405,6 +409,12 @@ value will be `null` (`None` in Scala) when the corresponding actual entry is mi
 a given configuration instance.
 
 
+## configuration template
+
+tscfg can also generate user-oriented configuration templates from given config specs.
+See [this wiki](https://github.com/carueda/tscfg/wiki/template-generation).
+
+
 ## FAQ
 
 **But I can just access the configuration values directly with Typesafe Config 

src/main/resources/application.conf

@@ -1 +1 @@
-tscfg.version = 0.8.2
+tscfg.version = 0.8.3

src/main/scala/tscfg/Main.scala

@@ -6,7 +6,7 @@ import java.util.Date
 import com.typesafe.config.ConfigFactory
 import tscfg.generators.java.JavaGen
 import tscfg.generators.scala.ScalaGen
-import tscfg.generators.{Generator, GenOpts}
+import tscfg.generators.{GenOpts, Generator, TemplateOpts, TemplateGenerator}
 
 /**
   * The main program. Run with no arguments to see usage.
@@ -22,25 +22,32 @@ object Main {
 
   val defaultDestDir: String = "/tmp"
 
-  val usage: String = s"""
-                         |tscfg $version
-                         |Usage:  tscfg.Main --spec inputFile [options]
-                         |Options (default):
-                         |  --pn <packageName>                                     (${defaultGenOpts.packageName})
-                         |  --cn <className>                                       (${defaultGenOpts.className})
-                         |  --dd <destDir>                                         ($defaultDestDir)
-                         |  --j7                  generate code for java <= 7      (8)
-                         |  --scala               generate scala code              (java)
-                         |  --java                generate java code               (the default)
-                         |Output is written to $$destDir/$$className.ext
+  var templateOpts = TemplateOpts()
+
+  val usage: String =
+    s"""
+       |tscfg $version
+       |Usage:  tscfg.Main --spec inputFile [options]
+       |Options (default):
+       |  --pn <packageName>                                     (${defaultGenOpts.packageName})
+       |  --cn <className>                                       (${defaultGenOpts.className})
+       |  --dd <destDir>                                         ($defaultDestDir)
+       |  --j7                  generate code for java <= 7      (8)
+       |  --scala               generate scala code              (java)
+       |  --java                generate java code               (the default)
+       |  --tpl <filename>      generate config template         (no default)
+       |  --tpl.ind <string>    template indentation string      ("${templateOpts.indent}")
+       |  --tpl.cp <string>     prefix for template comments     ("${templateOpts.commentPrefix}")
+       |Output is written to $$destDir/$$className.ext
     """.stripMargin
 
   case class CmdLineOpts(inputFilename: Option[String] = None,
                          packageName: String = defaultGenOpts.packageName,
                          className: String =   defaultGenOpts.className,
                          destDir: String = defaultDestDir,
                          j7: Boolean = false,
-                         language: String = "java"
+                         language: String = "java",
+                         tplFilename: Option[String] = None
                         )
 
   def main(args: Array[String]): Unit = {
@@ -82,11 +89,22 @@ object Main {
         case "--java" :: rest =>
           traverseList(rest, opts.copy(language = "java"))
 
-        case opt :: nil =>
+        case "--tpl" :: filename :: rest =>
+          traverseList(rest, opts.copy(tplFilename = Some(filename)))
+
+        case "--tpl.ind" :: indent :: rest =>
+          templateOpts = templateOpts.copy(indent = indent)
+          traverseList(rest, opts)
+
+        case "--tpl.cp" :: prefixComment :: rest =>
+          templateOpts = templateOpts.copy(commentPrefix = prefixComment)
+          traverseList(rest, opts)
+
+        case opt :: _ =>
           println( s"""missing argument or unknown option: $opt""")
           sys.exit(0)
 
-        case nil => opts
+        case Nil => opts
       }
     }
 
@@ -145,14 +163,14 @@ object Main {
 
     out.close()
 
-    /*
-        opts.templates foreach { genTemplate =>
-          val destFile = new File(genTemplate.filename)
-          printf("%10s: %s\n", genTemplate.what, destFile.getAbsolutePath)
-          val out = new PrintWriter(destFile)
-          templateGenerator.generate(genTemplate.what, root, out)
-          out.close()
-        }
-    */
+    opts.tplFilename foreach { filename ⇒
+      println(s"generating template $filename")
+      val destFile = new File(filename)
+      val out = new PrintWriter(destFile)
+      val templater = new TemplateGenerator(templateOpts)
+      val template = templater.generate(objectType)
+      out.println(template)
+      out.close()
+    }
   }
 }

src/main/scala/tscfg/generators/TemplateGenerator.scala

@@ -0,0 +1,87 @@
+package tscfg.generators
+
+import tscfg.model._
+
+case class TemplateOpts(indent:        String = "  ",
+                        commentPrefix: String = "##"
+                       )
+
+class TemplateGenerator(opts: TemplateOpts) {
+  def generate(o: ObjectType): String = genObjectTypeMembers(o)
+
+  private def genObjectType(o: ObjectType): String = {
+    val members = opts.indent + genObjectTypeMembers(o).replaceAll("\n", "\n" + opts.indent)
+    s"""{
+       |$members
+       |}""".stripMargin
+  }
+
+  private def genObjectTypeMembers(o: ObjectType): String = {
+    val symbols = o.members.keys.toList.sorted
+    symbols.map { symbol ⇒
+      val a = o.members(symbol)
+
+      val (annotations, comments) = a.comments match {
+        case None ⇒ (List.empty, List.empty)
+        case Some(str) ⇒
+          val lines = str.split("\n").toList.filterNot(_.startsWith("!"))
+          lines.partition(_.startsWith("@"))
+      }
+
+      val cmn = if (comments.isEmpty) "" else {
+        opts.commentPrefix + comments.mkString("\n" + opts.commentPrefix) + "\n"
+      }
+
+      val opt = if (a.isOptional) "optional" else "required"
+      val dfl = a.default.map(d ⇒ s". Default: $d").getOrElse("")
+      val (typ, abbrev) = gen(a.t)
+      val abbrev2 = if (abbrev == abbrevObject) "section" else abbrev
+      val decl = opts.commentPrefix + s" '$symbol': $opt $abbrev2$dfl.\n"
+
+      val sysPropOpt: Option[String] = annotations.find(_.startsWith(sysPropAnn))
+        .map(_.substring(sysPropAnn.length).trim)
+
+      val envVarOpt: Option[String] = annotations.find(_.startsWith(envVarAnn))
+        .map(_.substring(envVarAnn.length).trim)
+
+      val assign = if (abbrev == abbrevObject)
+        symbol + " " + typ  // do not include `=' for an object
+      else if (isBasicAbbrev(abbrev))
+        symbol + " = " + "?"
+      else
+        symbol + " = " + typ
+
+      val assignSysProp = sysPropOpt.map(e ⇒ s"\n$symbol = $${$e}").getOrElse("")
+      val assignEnvVar  = envVarOpt.map(e ⇒ s"\n$symbol = $${?$e}").getOrElse("")
+
+      decl +
+        cmn +
+        (if (a.isOptional) "#" + assign.replaceAll("\n", "\n#") else assign) +
+        assignSysProp +
+        assignEnvVar
+
+    }.mkString("\n\n")
+  }
+
+  private def gen(typ: Type): (String,String) = typ match {
+    case o:ObjectType ⇒
+      (genObjectType(o), abbrevObject)
+
+    case b:BasicType  ⇒
+      val lc = b.toString.toLowerCase
+      (lc, lc)
+
+    case ListType(t)  ⇒
+      val (subTyp, abbrev) = gen(t)
+      (s"[$subTyp, ...]", abbrevListOf + " " + abbrev)
+  }
+
+  private def isBasicAbbrev(abbrev: String): Boolean =
+    abbrev != abbrevObject && !abbrev.startsWith(abbrevListOf)
+
+  private val abbrevObject = "object"
+  private val abbrevListOf = "list of"
+
+  private val envVarAnn  = "@envvar"
+  private val sysPropAnn = "@sysprop"
+}

src/main/tscfg/example/example4tpl.spec.conf

@@ -0,0 +1,33 @@
+#! Comments starting with #! are not transferred to template.
+# Description of the required endpoint section.
+endpoint {
+  # The path associated with the endpoint.
+  # For example, "/home/foo/bar"
+  #@envvar ENDPOINT_PATH
+  path = "string"
+
+  # Port for the endpoint service.
+  #@envvar ENDPOINT_PORT
+  port = "int | 8080"
+
+  # Configuration for notifications
+  notifications {
+    # Emails to send notifications to.
+    emails = [ {
+      email: string
+
+      name: "string?"
+    } ]
+  }
+
+  # Some optional stuff.
+  #@optional
+  stuff {
+    # Coeficient matrix
+    coefs: [[double]]
+
+    #@sysprop endpoint.port
+    port2: int
+  }
+}
+

src/main/tscfg/example/example4tpl.template.conf

@@ -0,0 +1,40 @@
+## 'endpoint': required section.
+## Description of the required endpoint section.
+endpoint {
+  ## 'notifications': required section.
+  ## Configuration for notifications
+  notifications {
+    ## 'emails': required list of object.
+    ## Emails to send notifications to.
+    emails = [{
+      ## 'email': required string.
+      email = ?
+
+      ## 'name': optional string.
+      #name = ?
+    }, ...]
+  }
+
+  ## 'path': required string.
+  ## The path associated with the endpoint.
+  ## For example, "/home/foo/bar"
+  path = ?
+  path = ${?ENDPOINT_PATH}
+
+  ## 'port': optional integer. Default: 8080.
+  ## Port for the endpoint service.
+  #port = ?
+  port = ${?ENDPOINT_PORT}
+
+  ## 'stuff': optional section.
+  ## Some optional stuff.
+  #stuff {
+  #  ## 'coefs': required list of list of double.
+  #  ## Coeficient matrix
+  #  coefs = [[double, ...], ...]
+  #  
+  #  ## 'port2': required integer.
+  #  port2 = ?
+  #  port2 = ${endpoint.port}
+  #}
+}