1.containerignore(28) Container User Manuals .containerignore(28)
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6 .containerignore(.dockerignore) - files to ignore buildah or podman
7 build context directory
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12 Before container engines build image, they look for a file named .con‐
13 tainerignore or .dockerignore in the root context directory. If one of
14 these file exists, the CLI modifies the context to exclude files and
15 directories that match patterns specified in the file. This avoids
16 adding them to images using the ADD or COPY instruction.
17 The CLI interprets the .containerignore or .dockerignore file as a new‐
20 line-separated list of patterns similar to the file globs of Unix
21 shells. For the purposes of matching, the root of the context is con‐
22 sidered to be both the working and the root directory. For example, the
23 patterns /foo/bar and foo/bar both exclude a file or directory named
24 bar in the foo subdirectory of PATH or in the root of the git reposi‐
25 tory located at URL. Neither excludes anything else.
26 If a line in .containerignore or .dockerignore file starts with # in
29 column 1, then this line is considered as a comment and is ignored be‐
30 fore interpreted by the CLI.
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35 Here is an example .containerignore file:
36 # comment
39 */temp*
40 */*/temp*
41 temp?
42 This file causes the following build behavior: Rule Behavior
46 # comment Ignored.
49 */temp* Exclude files and directories whose names start with temp in any immediate subdirectory of the root.
50 For example, the plain file /somedir/temporary.txt is excluded, as is the directory /somedir/temp.
51 */*/temp* Exclude files and directories starting with temp from any subdirectory that is two levels below the
52 root. For example, /somedir/subdir/temporary.txt is excluded.
53 temp? Exclude files and directories in the root directory whose names are a one-character extension of temp. For example, /tempa and /tempb are excluded.
54 Matching is done using Go’s filepath.Match rules. A preprocessing step
58 removes leading and trailing whitespace and eliminates . and .. ele‐
59 ments using Go’s filepath.Clean. Lines that are blank after preprocess‐
60 ing are ignored.
61 Beyond Go’s filepath.Match rules, Docker also supports a special wild‐
64 card string ** that matches any number of directories (including zero).
65 For example, */.go will exclude all files that end with .go that are
66 found in all directories, including the root of the build context.
67 Lines starting with ! (exclamation mark) can be used to make exceptions
70 to exclusions. The following is an example .containerignore file that
71 uses this mechanism:
72 *.md
75 !README.md
76 All markdown files except README.md are excluded from the context.
80 The placement of ! exception rules influences the behavior: the last
83 line of the .containerignore that matches a particular file determines
84 whether it is included or excluded. Consider the following example:
85 *.md
88 !README*.md
89 README-secret.md
90 No markdown files are included in the context except README files other
94 than README-secret.md.
95 Now consider this example:
98 *.md
101 README-secret.md
102 !README*.md
103 All of the README files are included. The middle line has no effect be‐
107 cause !README*.md matches README-secret.md and comes last.
108 You can even use the .containerignore file to exclude the Containerfile
111 or Dockerfile and .containerignore files. These files are still sent
112 to the daemon because it needs them to do its job. But the ADD and COPY
113 instructions do not copy them to the image.
114 Finally, you may want to specify which files to include in the context,
117 rather than which to exclude. To achieve this, specify * as the first
118 pattern, followed by one or more ! exception patterns.
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122 buildah-build(1), podman-build(1), docker-build(1)
123
127 *Sep 2021, Compiled by Dan Walsh (dwalsh at redhat dot com) based on
128 docker.com .dockerignore documentation.
129 Sep 2021 .containerignore(28)