✨ : HCL parsing

pom.xml

@@ -196,6 +196,13 @@
 			<groupId>org.springframework.security</groupId>
 			<artifactId>spring-security-oauth2-client</artifactId>
 		</dependency>
+
+		<!-- antlr for HCL parsing -->
+		<dependency>
+			<groupId>org.antlr</groupId>
+			<artifactId>antlr4-runtime</artifactId>
+			<version>4.7</version>
+		</dependency>
 	</dependencies>
 
 	<build>
@@ -254,6 +261,23 @@
 				<groupId>pl.project13.maven</groupId>
 				<artifactId>git-commit-id-plugin</artifactId>
 			</plugin>
+
+			<plugin>
+				<groupId>org.antlr</groupId>
+				<artifactId>antlr4-maven-plugin</artifactId>
+				<version>4.7</version>
+				<executions>
+					<execution>
+						<goals>
+							<goal>antlr4</goal>
+						</goals>
+						<configuration>
+							<visitor>true</visitor>
+							<listener>false</listener>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
 		</plugins>
 	</build>
 

src/main/antlr4/io/codeka/gaia/hcl/antlr/hcl.g4

@@ -0,0 +1,156 @@
+grammar hcl;
+
+file
+  : directive+
+  ;
+
+directive
+  : variableDirective
+  | outputDirective
+  ;
+
+variableDirective
+  : 'variable' STRING variableBlock
+  ;
+
+variableBlock
+  : '{' (variableType|variableDescription|variableDefault)+ '}'
+  ;
+
+outputDirective
+  : 'output' STRING outputBlock
+  ;
+
+outputBlock
+  : '{' (outputValue|outputDescription|outputSensitive)+ '}'
+  ;
+
+outputValue
+  : 'value' '=' expression
+  ;
+
+outputDescription
+  : 'description' '=' STRING
+  ;
+
+outputSensitive
+  : 'sensitive' '=' BOOLEAN
+  ;
+
+variableType
+  : 'type' '=' type
+  ;
+
+type
+  : TYPE
+  | 'list'
+  | 'list(' type ')'
+  | 'map(' type ')'
+  | 'object' '(' object ')'
+  ;
+
+object
+  : '{' '}'
+  | '{' field+ '}'
+  ;
+
+field: IDENTIFIER '=' expression;
+
+variableDescription
+  : 'description' '=' STRING
+  ;
+
+variableDefault
+  : 'default' '=' expression
+  ;
+
+expression
+  : STRING
+  | NUMBER
+  | BOOLEAN
+  | array
+  | object
+  | complexExpression
+  ;
+
+functionCall
+  : IDENTIFIER '(' expression ( ',' expression )* ','? ')'
+  ;
+
+complexExpression
+  : IDENTIFIER
+  | complexExpression '.' complexExpression // attribute access
+  | complexExpression '[' index ']' // indexed array access
+  | complexExpression '.' index // indexed attribute access
+  | functionCall
+  ;
+
+array
+  : '[' ']'
+  | '[' expression ( ',' expression )* ','? ']'
+  ;
+
+index
+  : NUMBER
+  | '*'
+  ;
+
+BOOLEAN
+  : 'true'
+  | '"true"'
+  | 'false'
+  | '"false"'
+  ;
+
+TYPE
+  : 'string'
+  | '"string"'
+  | 'number'
+  | '"number"'
+  | 'bool'
+  | '"bool"'
+  | 'any'
+  ;
+
+IDENTIFIER:         Letter LetterOrDigit*;
+
+fragment LetterOrDigit
+    : Letter
+    | [0-9]
+    ;
+fragment Letter
+    : [a-zA-Z$_] // these are the "java letters" below 0x7F
+    | ~[\u0000-\u007F\uD800-\uDBFF] // covers all characters above 0x7F which are not a surrogate
+    | [\uD800-\uDBFF] [\uDC00-\uDFFF] // covers UTF-16 surrogate pairs encodings for U+10000 to U+10FFFF
+    ;
+
+/**
+ * STRING Lexer Rule comes from the JSON grammar
+ * https://github.com/antlr/grammars-v4/blob/master/json/JSON.g4
+ */
+STRING
+   : '"' (ESC | SAFECODEPOINT)* '"'
+   ;
+
+fragment ESC
+   : '\\' (["\\/bfnrt] | UNICODE)
+   ;
+fragment UNICODE
+   : 'u' HEX HEX HEX HEX
+   ;
+fragment HEX
+   : [0-9a-fA-F]
+   ;
+fragment SAFECODEPOINT
+   : ~ ["\\\u0000-\u001F]
+   ;
+
+NUMBER
+   : '0' | [1-9] [0-9]*
+   ;
+
+// comments and whitespaces
+COMMENT:      '/*' .*? '*/' -> channel(HIDDEN);
+LINE_COMMENT: '//' ~[\r\n]* -> channel(HIDDEN);
+HAS_COMMENT:  '#' ~ [\r\n]* -> channel(HIDDEN);
+WS:           [ \t\r\n]+    -> channel(HIDDEN); // skip spaces, tabs, newlines

src/main/java/io/codeka/gaia/hcl/HclParser.kt

@@ -0,0 +1,40 @@
+package io.codeka.gaia.hcl
+
+import io.codeka.gaia.hcl.antlr.hclLexer
+import io.codeka.gaia.hcl.antlr.hclParser
+import io.codeka.gaia.modules.bo.Output
+import io.codeka.gaia.modules.bo.Variable
+import org.antlr.v4.runtime.CharStreams
+import org.antlr.v4.runtime.CommonTokenStream
+
+class HclParser {
+
+    private fun parseContent(content: String): HclVisitor {
+        // loading test file
+        val charStream = CharStreams.fromString(content)
+
+        // configuring antlr lexer
+        val lexer = hclLexer(charStream)
+
+        // using the lexer to configure a token stream
+        val tokenStream = CommonTokenStream(lexer)
+
+        // configuring antlr parser using the token stream
+        val parser = hclParser(tokenStream)
+
+        // visit the AST
+        val hclVisitor = HclVisitor()
+        hclVisitor.visit(parser.file())
+        return hclVisitor
+    }
+
+    fun parseVariables(content:String): List<Variable> {
+        val hclVisitor = parseContent(content)
+        return hclVisitor.variables
+    }
+
+    fun parseOutputs(content:String): List<Output> {
+        val hclVisitor = parseContent(content)
+        return hclVisitor.outputs
+    }
+}

src/main/java/io/codeka/gaia/hcl/HclVisitor.kt

@@ -0,0 +1,52 @@
+package io.codeka.gaia.hcl
+
+import io.codeka.gaia.hcl.antlr.hclBaseVisitor
+import io.codeka.gaia.hcl.antlr.hclParser
+import io.codeka.gaia.modules.bo.Output
+import io.codeka.gaia.modules.bo.Variable
+import java.util.*
+
+class HclVisitor : hclBaseVisitor<Unit>() {
+
+    var variables: MutableList<Variable> = LinkedList()
+    var outputs: MutableList<Output> = LinkedList()
+
+    private var currentVariable: Variable = Variable(name = "")
+    private var currentOutput: Output = Output()
+
+    override fun visitVariableDirective(ctx: hclParser.VariableDirectiveContext) {
+        currentVariable = Variable(name = ctx.STRING().text.removeSurrounding("\""))
+        variables.add(currentVariable)
+        visitChildren(ctx)
+    }
+
+    override fun visitVariableType(ctx: hclParser.VariableTypeContext) {
+        currentVariable.type = ctx.type().text.removeSurrounding("\"")
+    }
+
+    override fun visitVariableDefault(ctx: hclParser.VariableDefaultContext) {
+        currentVariable.defaultValue = ctx.expression().text.removeSurrounding("\"")
+    }
+
+    override fun visitVariableDescription(ctx: hclParser.VariableDescriptionContext) {
+        currentVariable.description = ctx.STRING().text.removeSurrounding("\"")
+    }
+
+    override fun visitOutputDirective(ctx: hclParser.OutputDirectiveContext) {
+        currentOutput = Output(name = ctx.STRING().text.removeSurrounding("\""))
+        outputs.add(currentOutput)
+        visitChildren(ctx)
+    }
+
+    override fun visitOutputDescription(ctx: hclParser.OutputDescriptionContext) {
+        currentOutput.description = ctx.STRING().text.removeSurrounding("\"")
+    }
+
+    override fun visitOutputValue(ctx: hclParser.OutputValueContext) {
+        currentOutput.value = ctx.expression().text.removeSurrounding("\"")
+    }
+
+    override fun visitOutputSensitive(ctx: hclParser.OutputSensitiveContext) {
+        currentOutput.sensitive = ctx.BOOLEAN().text.removeSurrounding("\"")
+    }
+}

src/main/java/io/codeka/gaia/modules/bo/Output.kt

@@ -0,0 +1,10 @@
+package io.codeka.gaia.modules.bo
+
+/**
+ * Represents a module output
+ */
+data class Output(
+        var name: String = "",
+        var value: String = "",
+        var description: String = "",
+        var sensitive: String = "false");

src/main/java/io/codeka/gaia/modules/bo/TerraformModule.java

@@ -23,7 +23,7 @@ public class TerraformModule {
     private String directory;
 
     @Valid
-    private List<TerraformVariable> variables = new ArrayList<>();
+    private List<Variable> variables = new ArrayList<>();
 
     @NotBlank
     private String name;
@@ -93,11 +93,11 @@ public String getDescription() {
         return description;
     }
 
-    public List<TerraformVariable> getVariables() {
+    public List<Variable> getVariables() {
         return variables;
     }
 
-    public void setVariables(List<TerraformVariable> variables) {
+    public void setVariables(List<Variable> variables) {
         this.variables = variables;
     }