Use smaller windows base image (#12)

docker/Dockerfile.windows.amd64.1809

@@ -1,12 +1,21 @@
 # escape=`
 
-FROM mcr.microsoft.com/windows/servercore:1809
+FROM mcr.microsoft.com/windows/servercore:1809 as base
 SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]
 USER ContainerAdministrator
 
 ENV GODEBUG=netdns=go
 RUN mkdir /bin
 RUN Invoke-WebRequest https://releases.jfrog.io/artifactory/jfrog-cli/v2/2.10.0/jfrog-cli-windows-amd64/jfrog.exe -OutFile C:/bin/jfrog.exe
+
+FROM mcr.microsoft.com/powershell:nanoserver-1809
+COPY --from=base /bin /bin
+
 ADD release/windows/amd64/plugin C:/bin/drone-artifactory.exe
 
+# https://github.com/PowerShell/PowerShell/issues/6211#issuecomment-367477137
+USER ContainerAdministrator
+RUN setx /M PATH "%PATH%;C:\Program Files\PowerShell"
+
+SHELL ["pwsh", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]
 ENTRYPOINT [ "C:\\bin\\drone-artifactory.exe" ]

docker/Dockerfile.windows.amd64.1909

@@ -1,11 +1,21 @@
 # escape=`
-FROM mcr.microsoft.com/windows/servercore:1909
+
+FROM mcr.microsoft.com/windows/servercore:1909 as base
 SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]
 USER ContainerAdministrator
 
 ENV GODEBUG=netdns=go
 RUN mkdir /bin
 RUN Invoke-WebRequest https://releases.jfrog.io/artifactory/jfrog-cli/v2/2.10.0/jfrog-cli-windows-amd64/jfrog.exe -OutFile C:/bin/jfrog.exe
+
+FROM mcr.microsoft.com/powershell:nanoserver-1909
+COPY --from=base /bin /bin
+
 ADD release/windows/amd64/plugin C:/bin/drone-artifactory.exe
 
+# https://github.com/PowerShell/PowerShell/issues/6211#issuecomment-367477137
+USER ContainerAdministrator
+RUN setx /M PATH "%PATH%;C:\Program Files\PowerShell"
+
+SHELL ["pwsh", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]
 ENTRYPOINT [ "C:\\bin\\drone-artifactory.exe" ]

plugin/plugin.go

@@ -80,7 +80,7 @@ func Exec(ctx context.Context, args Args) error {
 
 func getShell() (string, string) {
 	if runtime.GOOS == "windows" {
-		return "powershell", "-Command"
+		return "pwsh", "-Command"
 	}
 
 	return "sh", "-c"