我正在尝试在我的本地计算机上设置 Prediction.io文本分类引擎。但是，在尝试 时pio build，我收到以下消息：
[ERROR] [Console$] No valid engine instance found for engine iMXSzwtuLBqTGDQVWFwhXLyX3MELx6Ox 2089ace31214efdc353ab45e911b7524222d7ab6.
Try running 'train' before 'deploy'. Aborting.
如教程中所述，我已经导入了示例数据。我能够毫无问题地构建和训练引擎。任何想法为什么它无法找到有效的引擎实例？
相关信息：
pio build：
[INFO] [Console$] Using existing engine manifest JSON at ~/prediction_io/text_classification/manifest.json
[INFO] [Console$] Using command '/usr/local/Cellar/predictionio/0.9.5/libexec/sbt/sbt' at the current working directory to build.
[INFO] [Console$] If the path above is incorrect, this process will fail.
[INFO] [Console$] Uber JAR disabled. Making sure lib/pio-assembly-0.9.5.jar is absent.
[INFO] [Console$] Going to run: /usr/local/Cellar/predictionio/0.9.5/libexec/sbt/sbt package assemblyPackageDependency
[INFO] [Console$] Build finished successfully.
[INFO] [Console$] Looking for an engine...
[INFO] [Console$] Found com-example_2.10-0.1-SNAPSHOT.jar
[INFO] [Console$] Found com.example-assembly-0.1-SNAPSHOT-deps.jar
[INFO] [RegisterEngine$] Registering engine iMXSzwtuLBqTGDQVWFwhXLyX3MELx6Ox 2089ace31214efdc353ab45e911b7524222d7ab6
[INFO] [Console$] Your engine is ready for training.
pio train：
INFO] [Console$] Using existing engine manifest JSON at ~/prediction_io/text_classification/manifest.json
[INFO] [Runner$] Submission command: /usr/local/opt/apache-spark/bin/spark-submit --class io.prediction.workflow.CreateWorkflow --jars file:~/prediction_io/text_classification/target/scala-2.10/com-example_2.10-0.1-SNAPSHOT.jar,file:~/prediction_io/text_classification/target/scala-2.10/com.example-assembly-0.1-SNAPSHOT-deps.jar --files file:/usr/local/Cellar/predictionio/0.9.5/libexec/conf/log4j.properties --driver-class-path /usr/local/Cellar/predictionio/0.9.5/libexec/conf:/usr/local/opt/elasticsearch/config file:/usr/local/Cellar/predictionio/0.9.5/libexec/lib/pio-assembly-0.9.5.jar --engine-id iMXSzwtuLBqTGDQVWFwhXLyX3MELx6Ox --engine-version 2089ace31214efdc353ab45e911b7524222d7ab6 --engine-variant file:~/prediction_io/text_classification/engine.json --verbosity 0 --json-extractor Both --env PIO_ENV_LOADED=1,PIO_STORAGE_REPOSITORIES_METADATA_NAME=pio_meta,PIO_FS_BASEDIR=~/.pio_store,PIO_HOME=/usr/local/Cellar/predictionio/0.9.5/libexec,PIO_FS_ENGINESDIR=~/.pio_store/engines,PIO_STORAGE_SOURCES_PGSQL_URL=jdbc:postgresql://localhost/pio,PIO_STORAGE_REPOSITORIES_METADATA_SOURCE=PGSQL,PIO_STORAGE_REPOSITORIES_MODELDATA_SOURCE=PGSQL,PIO_STORAGE_REPOSITORIES_EVENTDATA_NAME=pio_event,PIO_STORAGE_SOURCES_PGSQL_PASSWORD=,PIO_STORAGE_SOURCES_PGSQL_TYPE=jdbc,PIO_FS_TMPDIR=~/.pio_store/tmp,PIO_STORAGE_SOURCES_PGSQL_USERNAME=pio,PIO_STORAGE_REPOSITORIES_MODELDATA_NAME=pio_model,PIO_STORAGE_REPOSITORIES_EVENTDATA_SOURCE=PGSQL,PIO_CONF_DIR=/usr/local/Cellar/predictionio/0.9.5/libexec/conf
/usr/local/Cellar/predictionio/0.9.5/libexec/conf/pio-env.sh: line 55: PIO_STORAGE_SOURCES_PGSQL_PASSWORD: command not found
pio status：
[INFO] [Console$] Inspecting PredictionIO...
[INFO] [Console$] PredictionIO 0.9.5 is installed at /usr/local/Cellar/predictionio/0.9.5/libexec
[INFO] [Console$] Inspecting Apache Spark...
[INFO] [Console$] Apache Spark is installed at /usr/local/opt/apache-spark
[WARN] [Console$] Apache Spark version information cannot be found. If you are using a developmental tree, please make sure you are using a version of at least 1.3.0.
[INFO] [Console$] Inspecting storage backend connections...
[INFO] [Storage$] Verifying Meta Data Backend (Source: PGSQL)...
[INFO] [Storage$] Verifying Model Data Backend (Source: PGSQL)...
[INFO] [Storage$] Verifying Event Data Backend (Source: PGSQL)...
[INFO] [Storage$] Test writing to Event Store (App Id 0)...
[INFO] [Console$] (sleeping 5 seconds for all messages to show up...)
[INFO] [Console$] Your system is all ready to go.