Android: Added download models into build.gradle for android example

Change: 150471440

4 files changed, 86 insertions, 28 deletions

diff --git a/tensorflow/examples/android/BUILD b/tensorflow/examples/android/BUILD
index 83b9dc49a3..c3206d81dc 100644
--- a/tensorflow/examples/android/BUILD
+++ b/tensorflow/examples/android/BUILD
@@ -86,6 +86,7 @@ android_binary(
     ],
 )
 
+# LINT.IfChange
 filegroup(
     name = "external_assets",
     srcs = [
@@ -94,6 +95,7 @@ filegroup(
         "@stylize//:model_files",
     ],
 )
+# LINT.ThenChange(//tensorflow/examples/android/download-models.gradle)
 
 filegroup(
     name = "all_files",
diff --git a/tensorflow/examples/android/README.md b/tensorflow/examples/android/README.md
index 3182b8f211..81a2a66617 100644
--- a/tensorflow/examples/android/README.md
+++ b/tensorflow/examples/android/README.md
@@ -112,10 +112,10 @@ The NDK API level may remain at 14.
 The TensorFlow `GraphDef`s that contain the model definitions and weights
 are not packaged in the repo because of their size. They are downloaded
 automatically and packaged with the APK by Bazel via a new_http_archive defined
-in `WORKSPACE` during the build process.
+in `WORKSPACE` during the build process, and by Gradle via download-models.gradle.
 
-**Optional**: If you wish to place the models in your assets manually (E.g. for
-non-Bazel builds), remove all of the `model_files` entries from the `assets`
+**Optional**: If you wish to place the models in your assets manually,
+remove all of the `model_files` entries from the `assets`
 list in `tensorflow_demo` found in the `[BUILD](BUILD)` file. Then download
 and extract the archives yourself to the `assets` directory in the source tree:
 
@@ -131,6 +131,10 @@ done
 This will extract the models and their associated metadata files to the local
 assets/ directory.
 
+If you are using Gradle, make sure to remove download-models.gradle reference
+from build.gradle after your manually download models; otherwise gradle
+might download models again and overwrite your models.
+
 ##### Build
 
 After editing your WORKSPACE file to update the SDK/NDK configuration,
diff --git a/tensorflow/examples/android/build.gradle b/tensorflow/examples/android/build.gradle
index ebfaf6539b..414a97713e 100644
--- a/tensorflow/examples/android/build.gradle
+++ b/tensorflow/examples/android/build.gradle
@@ -41,9 +41,6 @@ if (buildWithMake) {
 // automatically.
 def makeNdkRoot = System.getenv('NDK_ROOT')
 
-// Location of model files required as assets
-def externalModelData = '../../../bazel-tensorflow/external'
-
 // If building with Bazel, this is the location of the bazel binary.
 // NOTE: Bazel does not yet support building for Android on Windows,
 // so in this case the Makefile build must be used as described above.
@@ -52,6 +49,10 @@ def bazelLocation = '/usr/local/bin/bazel'
 project.buildDir = 'gradleBuild'
 getProject().setBuildDir('gradleBuild')
 
+// import DownloadModels task
+project.ext.ASSET_DIR = projectDir.toString() + '/assets'
+project.ext.TMP_DIR   = project.buildDir.toString() + '/downloads'
+
 buildscript {
     repositories {
         jcenter()
@@ -95,7 +96,7 @@ android {
             aidl.srcDirs = ['src']
             renderscript.srcDirs = ['src']
             res.srcDirs = ['res']
-            assets.srcDirs = ['assets']
+            assets.srcDirs = [project.ext.ASSET_DIR]
             jniLibs.srcDirs = ['libs']
         }
 
@@ -127,10 +128,6 @@ task buildNativeMake(type: Exec) {
          //, '-T'  // Uncomment to skip protobuf and speed up subsequent builds.
 }
 
-task buildExternalAssets(type: Exec) {
-    commandLine bazelLocation, 'build',  '//tensorflow/examples/android:external_assets'
-    outputs.files(externalModelData)
-}
 
 task copyNativeLibs(type: Copy) {
     from demoLibPath
@@ -141,22 +138,13 @@ task copyNativeLibs(type: Copy) {
     fileMode 0644
 }
 
-task copyExternalAssets(type: Copy) {
-    from file(externalModelData).listFiles()
-    include '*.pb'
-    include '*.txt'
-    include 'thumbnails/*.jpg'
-    into 'assets'
-    fileMode 0644
-    dependsOn buildExternalAssets
-}
-
-def copyTasks = [copyNativeLibs]
-if (!buildWithMake) {
-    // copyExternalAssets uses bazel, so only run it when requested.
-    copyTasks.add(copyExternalAssets)
-}
-assemble.dependsOn copyTasks
+assemble.dependsOn copyNativeLibs
 afterEvaluate {
-    assembleDebug.dependsOn copyTasks
+    assembleDebug.dependsOn copyNativeLibs
+    assembleRelease.dependsOn copyNativeLibs
 }
+
+// Download default models; if you wish to use your own models then
+// place them in the "assets" directory and comment out this line.
+apply from: "download-models.gradle"
+
diff --git a/tensorflow/examples/android/download-models.gradle b/tensorflow/examples/android/download-models.gradle
new file mode 100644
index 0000000000..d60df15f08
--- /dev/null
+++ b/tensorflow/examples/android/download-models.gradle
@@ -0,0 +1,64 @@
+/*
+ * download-models.gradle
+ *     Downloads model files from ${MODEL_URL} into application's asset folder
+ * Input:
+ *     project.ext.TMP_DIR: absolute path to hold downloaded zip files
+ *     project.ext.ASSET_DIR: absolute path to save unzipped model files
+ * Output:
+ *     3 model files will be downloaded into given folder of ext.ASSET_DIR
+ */
+// hard coded model files
+// LINT.IfChange
+def models = ['inception5h.zip',
+              'mobile_multibox_v1a.zip',
+              'stylize_v1.zip']
+// LINT.ThenChange(//tensorflow/examples/android/BUILD)
+
+// Root URL for model archives
+def MODEL_URL = 'https://storage.googleapis.com/download.tensorflow.org/models'
+
+buildscript {
+    repositories {
+        jcenter()
+    }
+    dependencies {
+        classpath 'de.undercouch:gradle-download-task:3.2.0'
+    }
+}
+
+import de.undercouch.gradle.tasks.download.Download
+task downloadFile(type: Download){
+    for (f in models) {
+        src "${MODEL_URL}/" + f
+    }
+    dest new File(project.ext.TMP_DIR)
+    overwrite true
+}
+
+task extractModels(type: Copy) {
+    for (f in models) {
+        from zipTree(project.ext.TMP_DIR + '/' + f)
+    }
+
+    into file(project.ext.ASSET_DIR)
+    fileMode  0644
+    exclude '**/LICENSE'
+
+    dependsOn downloadFile
+}
+
+afterEvaluate {
+    // if models are not available, download & unzip them
+    def needDownload = false
+    for (f in models) {
+        if (!(new File(project.ext.TMP_DIR + '/' + f)).exists()) {
+            needDownload = true
+        }
+    }
+
+    if (needDownload) {
+        assembleDebug.dependsOn extractModels
+        assembleRelease.dependsOn extractModels
+    }
+}
+