Summary

Docker allows building your own custom image from the official Confluence image available at Docker Hub.

However, by following the exact same steps described in the Advanced Configuration section to build the new image on Windows (without customizing any file), you may run into an error when trying to run the container using that image.

Environment

• Git for Windows (used to clone the official repository)
• Docker (to build the new image)
• Windows OS

Diagnosis

• When trying to run a new container using the newly built image will give you the following error message:

  $ docker run -p 8090:8090 --name="newContainer" -v confluence:/var/atlassian/application-data/confluence newImage
  Unknown option: -
  usage: /usr/bin/python3 [option] ... [-c cmd | -m mod | file | -] [arg] ...
  Try `python -h' for more information.

• When inspecting the container logs, will give you the same error message

  $ docker logs newContainer
  Unknown option: -
  usage: /usr/bin/python3 [option] ... [-c cmd | -m mod | file | -] [arg] ...
  Try `python -h' for more information.

• Using a hexdump on the entrypoint.py checked out from the repository on Windows will present several 0d 0a byte sequences:

  $ hexdump entrypoint.py 
  0000000 23 21 2f 75 73 72 2f 62 69 6e 2f 70 79 74 68 6f
  0000010 6e 33 20 2d 42 0d 0a 0d 0a 66 72 6f 6d 20 65 6e
  0000020 74 72 79 70 6f 69 6e 74 5f 68 65 6c 70 65 72 73
  0000030 20 69 6d 70 6f 72 74 20 65 6e 76 2c 20 67 65 6e
  0000040 5f 63 66 67 2c 20 73 74 72 32 62 6f 6f 6c 2c 20
  0000050 73 74 61 72 74 5f 61 70 70 0d 0a 0d 0a 0d 0a 52
  0000060 55 4e 5f 55 53 45 52 20 3d 20 65 6e 76 5b 27 72
  0000070 75 6e 5f 75 73 65 72 27 5d 0d 0a 52 55 4e 5f 47
  0000080 52 4f 55 50 20 3d 20 65 6e 76 5b 27 72 75 6e 5f
  0000090 67 72 6f 75 70 27 5d 0d 0a 43 4f 4e 46 4c 55 45
  00000a0 4e 43 45 5f 49 4e 53 54 41 4c 4c 5f 44 49 52 20
  00000b0 3d 20 65 6e 76 5b 27 63 6f 6e 66 6c 75 65 6e 63
  00000c0 65 5f 69 6e 73 74 61 6c 6c 5f 64 69 72 27 5d 0d
  00000d0 0a 43 4f 4e 46 4c 55 45 4e 43 45 5f 48 4f 4d 45
  00000e0 20 3d 20 65 6e 76 5b 27 63 6f 6e 66 6c 75 65 6e
  00000f0 63 65 5f 68 6f 6d 65 27 5d 0d 0a 0d 0a 67 65 6e
  0000100 5f 63 66 67 28 27 73 65 72 76 65 72 2e 78 6d 6c
  0000110 2e 6a 32 27 2c 20 66 27 7b 43 4f 4e 46 4c 55 45
  0000120 4e 43 45 5f 49 4e 53 54 41 4c 4c 5f 44 49 52 7d
  0000130 2f 63 6f 6e 66 2f 73 65 72 76 65 72 2e 78 6d 6c
  0000140 27 29 0d 0a 67 65 6e 5f 63 66 67 28 27 73 65 72
  0000150 61 70 68 2d 63 6f 6e 66 69 67 2e 78 6d 6c 2e 6a
  0000160 32 27 2c 0d 0a 20 20 20 20 20 20 20 20 66 27 7b
  0000170 43 4f 4e 46 4c 55 45 4e 43 45 5f 49 4e 53 54 41
  0000180 4c 4c 5f 44 49 52 7d 2f 63 6f 6e 66 6c 75 65 6e
  0000190 63 65 2f 57 45 42 2d 49 4e 46 2f 63 6c 61 73 73
  00001a0 65 73 2f 73 65 72 61 70 68 2d 63 6f 6e 66 69 67
  00001b0 2e 78 6d 6c 27 29 0d 0a 67 65 6e 5f 63 66 67 28
  00001c0 27 63 6f 6e 66 6c 75 65 6e 63 65 2d 69 6e 69 74
  00001d0 2e 70 72 6f 70 65 72 74 69 65 73 2e 6a 32 27 2c
  00001e0 0d 0a 20 20 20 20 20 20 20 20 66 27 7b 43 4f 4e
  00001f0 46 4c 55 45 4e 43 45 5f 49 4e 53 54 41 4c 4c 5f
  0000200 44 49 52 7d 2f 63 6f 6e 66 6c 75 65 6e 63 65 2f
  0000210 57 45 42 2d 49 4e 46 2f 63 6c 61 73 73 65 73 2f
  0000220 63 6f 6e 66 6c 75 65 6e 63 65 2d 69 6e 69 74 2e
  0000230 70 72 6f 70 65 72 74 69 65 73 27 29 0d 0a 67 65
  0000240 6e 5f 63 66 67 28 27 63 6f 6e 66 6c 75 65 6e 63
  0000250 65 2e 63 66 67 2e 78 6d 6c 2e 6a 32 27 2c 20 66
  0000260 27 7b 43 4f 4e 46 4c 55 45 4e 43 45 5f 48 4f 4d
  0000270 45 7d 2f 63 6f 6e 66 6c 75 65 6e 63 65 2e 63 66
  0000280 67 2e 78 6d 6c 27 2c 0d 0a 20 20 20 20 20 20 20
  0000290 20 75 73 65 72 3d 52 55 4e 5f 55 53 45 52 2c 20
  00002a0 67 72 6f 75 70 3d 52 55 4e 5f 47 52 4f 55 50 2c
  00002b0 20 6f 76 65 72 77 72 69 74 65 3d 46 61 6c 73 65
  00002c0 29 0d 0a 0d 0a 73 74 61 72 74 5f 61 70 70 28 66
  00002d0 27 7b 43 4f 4e 46 4c 55 45 4e 43 45 5f 49 4e 53
  00002e0 54 41 4c 4c 5f 44 49 52 7d 2f 62 69 6e 2f 73 74
  00002f0 61 72 74 2d 63 6f 6e 66 6c 75 65 6e 63 65 2e 73
  0000300 68 20 2d 66 67 27 2c 20 43 4f 4e 46 4c 55 45 4e
  0000310 43 45 5f 48 4f 4d 45 2c 20 6e 61 6d 65 3d 27 43
  0000320 6f 6e 66 6c 75 65 6e 63 65 27 29 0d 0a         
  000032d

Cause

Git for Windows is configured to Checkout Windows-style.

There's a slight difference on how Windows and Unix systems handle line-endings on text files. Unix uses the line-feed character (/n, 0x0a) while Windows will insert an additional carriage-return character (/r/n, 0x0d 0x0a).

Solution

1. Follow the official Git Documentation to set the core.autocrlf as false, in Windows:

   git config --global core.autocrlf false

   This will prevent Windows from automatically adding the carriage-return character at the end of text files.

2. Clone the official Docker image repository again
3. Re-build the image