fix several issues when building a docker image

Dockerfile

@@ -3,17 +3,21 @@ FROM golang:latest as BUILDER
 MAINTAINER TommyLike<[email protected]>
 
 # build binary
-COPY . /go/src/github.com/opensourceways/app-cla-server
-RUN cd /go/src/github.com/opensourceways/app-cla-server && CGO_ENABLED=1 go build -v -o ./cla-server main.go
+ARG GOPROXY
+WORKDIR /go/src/github.com/opensourceways/app-cla-server
+COPY ./ .
+RUN CGO_ENABLED=1 go build -v -o ./cla-server main.go
 
 # copy binary config and utils
-FROM golang:latest
-RUN apt-get update && apt-get install -y python3 && apt-get install -y python3-pip && pip3 install PyPDF2 && mkdir -p /opt/app/
-COPY ./conf /opt/app/conf
-COPY ./util/merge-signature.py /opt/app/util/merge-signature.py
+FROM python:latest
+ARG GOPROXY
+RUN if [ "$GOPROXY" != "" ]; then pip config set global.index-url https://pypi.tuna.tsinghua.edu.cn/simple; fi
+RUN pip install PyPDF2
+WORKDIR /opt/app/
+COPY ./conf ./conf
+COPY ./util/merge-signature.py ./util
 # overwrite config yaml
-COPY ./deploy/app.conf /opt/app/conf
-COPY  --from=BUILDER /go/src/github.com/opensourceways/app-cla-server/cla-server /opt/app
+COPY ./deploy/app.conf ./conf
+COPY  --from=BUILDER /go/src/github.com/opensourceways/app-cla-server/cla-server .
 
-WORKDIR /opt/app/
 ENTRYPOINT ["/opt/app/cla-server"]

conf/app.conf

@@ -15,7 +15,7 @@ api_token_expiry = 3600
 api_token_key = fsfsfsafsfsasaf242342424sdfs;.]{77&&&
 
 pdf_org_signature_dir = ./conf/org_signature_pdf
-pdf_out_dir = ./conf/pdf
+pdf_out_dir = ./conf/pdfs
 
 code_platforms = ./conf/code_platforms.yaml
 email_platforms = ./conf/email.yaml