Expression file references in Vespa models

4 files changed, 45 insertions, 8 deletions

diff --git a/model-integration/src/main/java/ai/vespa/rankingexpression/importer/ImportedModel.java b/model-integration/src/main/java/ai/vespa/rankingexpression/importer/ImportedModel.java
index 90529ccdca0..58962d1a5ff 100644
--- a/model-integration/src/main/java/ai/vespa/rankingexpression/importer/ImportedModel.java
+++ b/model-integration/src/main/java/ai/vespa/rankingexpression/importer/ImportedModel.java
@@ -4,10 +4,16 @@ package ai.vespa.rankingexpression.importer;
 import com.google.common.collect.ImmutableMap;
 import ai.vespa.rankingexpression.importer.configmodelview.ImportedMlFunction;
 import ai.vespa.rankingexpression.importer.configmodelview.ImportedMlModel;
+import com.yahoo.config.application.api.ApplicationPackage;
+import com.yahoo.io.IOUtils;
 import com.yahoo.searchlib.rankingexpression.RankingExpression;
+import com.yahoo.searchlib.rankingexpression.parser.ParseException;
 import com.yahoo.tensor.Tensor;
 import com.yahoo.tensor.TensorType;
 
+import java.io.File;
+import java.io.IOException;
+import java.io.StringReader;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
@@ -115,6 +121,41 @@ public class ImportedModel implements ImportedMlModel {
     public void expression(String name, RankingExpression expression) { expressions.put(name, expression); }
     public void function(String name, RankingExpression expression) { functions.put(name, expression); }
 
+    public void expression(String name, String expression) {
+        try {
+            expression = expression.trim();
+            if ( expression.startsWith("file:")) {
+                String filePath = expression.substring("file:".length()).trim();
+                if ( ! filePath.endsWith(ApplicationPackage.RANKEXPRESSION_NAME_SUFFIX))
+                    filePath = filePath + ApplicationPackage.RANKEXPRESSION_NAME_SUFFIX;
+                expression = IOUtils.readFile(relativeFile(filePath, "function '" + name + "'"));
+            }
+            expression(name, new RankingExpression(expression));
+        }
+        catch (IOException e) {
+            throw new IllegalArgumentException("Could not read file referenced in '" + name + "'");
+        }
+        catch (ParseException e) {
+            throw new IllegalArgumentException("Could not parse function '" + name + "'", e);
+        }
+    }
+
+    /**
+     * Returns a reference to the File at a path given relative to the source root of this model
+     *
+     * @throws IllegalArgumentException if the path is illegal or non-existent
+     */
+    public File relativeFile(String relativePath, String descriptionOfPath) {
+        File file = new File(new File(source()).getParent(), relativePath);
+        if (file.isAbsolute())
+            throw new IllegalArgumentException(descriptionOfPath + " uses the absolute file path '" + relativePath +
+                                               "'. File paths must be relative to the directory referencing them");
+        if ( ! file.exists())
+            throw new IllegalArgumentException(descriptionOfPath + " references '" + relativePath +
+                                               "', but this file does not exist");
+        return file;
+    }
+
     /**
      * Returns all the output expressions of this indexed by name. The names consist of one or two parts
      * separated by dot, where the first part is the signature name
diff --git a/model-integration/src/main/javacc/ModelParser.jj b/model-integration/src/main/javacc/ModelParser.jj
index 5dde54e88e2..a7822cd1a00 100644
--- a/model-integration/src/main/javacc/ModelParser.jj
+++ b/model-integration/src/main/javacc/ModelParser.jj
@@ -180,12 +180,7 @@ void function() :
       ")"
       lbrace() expression = expression() (<NL>)* <RBRACE> )
     {
-        try {
-            model.expression(name, new RankingExpression(expression));
-        }
-        catch (com.yahoo.searchlib.rankingexpression.parser.ParseException e) {
-            throw new IllegalArgumentException("Could not parse function '" + name + "'", e);
-        }
+        model.expression(name, expression);
     }
 }
 
@@ -280,7 +275,7 @@ Tensor largeConstantBody(String name) :
     )+
     {
         try {
-            return JsonFormat.decode(type, IOUtils.readFileBytes(new File(new File(model.source()).getParent(), path)));
+            return JsonFormat.decode(type, IOUtils.readFileBytes(model.relativeFile(path, "constant '" + name + "'")));
         }
         catch (Exception e) {
             throw new IllegalArgumentException("Could not read constant '" + name + "'", e);
diff --git a/model-integration/src/test/models/vespa/example.model b/model-integration/src/test/models/vespa/example.model
index 66d21cfc53f..6d660732db9 100644
--- a/model-integration/src/test/models/vespa/example.model
+++ b/model-integration/src/test/models/vespa/example.model
@@ -15,7 +15,7 @@ model example {
     }
 
     function foo1() {
-        expression: reduce(sum(input1 * input2, name) * constant1, max, x) * constant2
+        expression: file:test.expression
     }
 
     function foo2() {
diff --git a/model-integration/src/test/models/vespa/test.expression b/model-integration/src/test/models/vespa/test.expression
new file mode 100644
index 00000000000..5db8a720498
--- /dev/null
+++ b/model-integration/src/test/models/vespa/test.expression
@@ -0,0 +1 @@
+reduce(sum(input1 * input2, name) * constant1, max, x) * constant2
\ No newline at end of file