fix issue with api docs

docs/build.gradle

@@ -1,3 +1,5 @@
+import java.nio.file.Files
+
 apply plugin: 'org.jetbrains.dokka'
 apply plugin: 'kotlin'
 
@@ -62,8 +64,14 @@ task dokkaJavadoc(type: org.jetbrains.dokka.gradle.DokkaTask) {
 task buildDocs(dependsOn: ['apidocs', 'makeDocs'])
 task apidocs(dependsOn: ['dokka', 'dokkaJavadoc'])
 
-task makeDocs(type: Exec) {
-    commandLine "docker", "run", "-v", "${project.projectDir}:/opt/docs_builder", "roastario/docs-builder:latest", "bash",  "-c", "rm -rf build && rm -rf virtualenv && install-docsite-requirements.sh && make-docsite.sh"
+task makeDocs(type: Exec, dependsOn: ['ensureBuildFolderPresent']) {
+    commandLine "docker", "run", "-v", "${project.projectDir}:/opt/docs_builder", "corda/docs-builder:latest", "bash",  "-c", "make-docsite.sh"
+}
+
+task ensureBuildFolderPresent{
+    doLast{
+        Files.createDirectories(new File(project.buildDir, "html").toPath())
+    }
 }
 
 apidocs.shouldRunAfter makeDocs

docs/docs_builder/Dockerfile

@@ -1,6 +1,7 @@
 FROM python:2-stretch
 
 RUN apt-get update && apt-get install -y texlive preview-latex-style texlive-generic-extra texlive-latex-extra latexmk dos2unix
-VOLUME /opt/docs_builder
 ENV PATH="/opt/docs_builder:${PATH}"
-WORKDIR /opt/docs_builder
+WORKDIR /opt/docs_builder
+COPY requirements.txt requirements.txt
+RUN pip install -r requirements.txt

docs/make-docsite.sh

@@ -1,16 +1,4 @@
 #!/usr/bin/env bash
-# The purpose of this file is to make the docsite in a python virtualenv
-# You can call it manually if running make manually, otherwise gradle will run it for you
-
-# Activate the virtualenv
-if [ -d "virtualenv/bin" ]
-then
-    # it's a Unix system
-    source virtualenv/bin/activate
-else
-    source virtualenv/Scripts/activate
-fi
-
 echo "Generating PDF document ..."
 make latexpdf