GCPへPythonWEBアプリをデプロイした際のエラー

Question

pythonのwebアプリをGoogle cloud platformへデプロイを試みておりますがエラー対応で詰んでおります。

ローカルでは問題なく動作しており、GCPの初期設定等も問題なくできていると思われるのですが・・・。
以下ビルドログです。

$ gcloud app deploy
Services to deploy:

descriptor:      [/project/app.yaml]
source:          [/project]
target project:  [project-ID]
target service:  [default]
target version:  [20180330t215549]
target url:      [https://project.appspot.com]


Do you want to continue (Y/n)?  y

省略

Step #1: Collecting mecab-python3==0.7 (from -r requirements.txt (line 44))
Step #1:   Downloading mecab-python3-0.7.tar.gz (41kB)
Step #1:     Complete output from command python setup.py egg_info:
Step #1:     /bin/sh: 1: mecab-config: not found
Step #1:     Traceback (most recent call last):
Step #1:       File "<string>", line 1, in <module>
Step #1:       File "/tmp/pip-build-uyt5ku_o/mecab-python3/setup.py", line 41, in <module>
Step #1:         include_dirs=cmd2("mecab-config --inc-dir"),
Step #1:       File "/tmp/pip-build-uyt5ku_o/mecab-python3/setup.py", line 21, in cmd2
Step #1:         return cmd1(strings).split()
Step #1:       File "/tmp/pip-build-uyt5ku_o/mecab-python3/setup.py", line 18, in cmd1
Step #1:         return os.popen(strings).readlines()[0][:-1]
Step #1:     IndexError: list index out of range
Step #1:     
Step #1:     ----------------------------------------
Step #1: Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-uyt5ku_o/mecab-python3/
Step #1: You are using pip version 9.0.1, however version 9.0.3 is available.
Step #1: You should consider upgrading via the 'pip install --upgrade pip' command.
Step #1: The command '/bin/sh -c pip install -r requirements.txt' returned a non-zero code: 1
Finished Step #1
ERROR
ERROR: build step 1 "gcr.io/cloud-builders/docker@sha256:b2d322e3dc5432f49ef915bbd8f961eed0feff9d60536c047a8670d983e7bb7c" failed: exit status 1
Step #1: 
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

ERROR: (gcloud.app.deploy) Cloud build failed. Check logs at https://console.cloud.google.com/gcr/builds/116eeb3b-4b2a-45e6-9df2-5b40bc0b6dd1?project= project-ID Failure status: UNKNOWN: Error Response: [2] Build failed; check build logs for details
MacBook-Pro:project$ 

おそらくMeCabのダウンロード行程でエラーが起きている事は推測できたのですが・・・

問題１
/tmp/pip-build-uyt5ku_o/mecab-python3/　というフォルダ（/pip-build-uyt5ku_o/）はローカルには存在しておらず、下記を参考にしましたが

http://tokyo-engineer.com/python3-6-1-mecab-python3-install/

mecab-python3自体はインストールできている様子

$ pip install mecab-python3
Requirement already satisfied: mecab-python3 in /usr/local/lib/python3.6/site-packages

下記場所には「setup.py」は存在していません。

$ which mecab-config
/usr/local/bin/mecab-config

問題２

You should consider upgrading via the 'pip install --upgrade pip' command

に従っても問題ない様子

$ pip install --upgrade pip
Requirement already up-to-date: pip in /usr/local/lib/python3.6/site-packages

問題３

The command '/bin/sh -c pip install -r requirements.txt' returned a non-zero code: 1

こちらはコマンドを打ってみたものの何をどうすればよいのか・・・。

色々と情報共有不足かと思いますが
どなたかご教授よろしくお願い致します。