debian-mirror-gitlab/doc/ci/yaml/script.md
2021-01-30 21:13:34 +05:30

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GitLab CI/CD script syntax

You can use special syntax in script sections to:

Split long commands

You can split long commands into multiline commands to improve readability with | (literal) and > (folded) YAML multiline block scalar indicators.

CAUTION: Warning: If multiple commands are combined into one command string, only the last command's failure or success is reported. Failures from earlier commands are ignored due to a bug. To work around this, run each command as a separate script: item, or add an exit 1 command to each command string.

You can use the | (literal) YAML multiline block scalar indicator to write commands over multiple lines in the script section of a job description. Each line is treated as a separate command. Only the first command is repeated in the job log, but additional commands are still executed:

job:
  script:
    - |
      echo "First command line."
      echo "Second command line."
      echo "Third command line."      

The example above renders in the job log as:

$ echo First command line # collapsed multiline command
First command line
Second command line.
Third command line.

The > (folded) YAML multiline block scalar indicator treats empty lines between sections as the start of a new command:

job:
  script:
    - >
      echo "First command line
      is split over two lines."

      echo "Second command line."      

This behaves similarly to multiline commands without the > or | block scalar indicators:

job:
  script:
    - echo "First command line
      is split over two lines."

      echo "Second command line."

Both examples above render in the job log as:

$ echo First command line is split over two lines. # collapsed multiline command
First command line is split over two lines.
Second command line.

When you omit the > or | block scalar indicators, GitLab concatenates non-empty lines to form the command. Make sure the lines can run when concatenated.

Shell here documents work with the | and > operators as well. The example below transliterates lower case letters to upper case:

job:
  script:
    - |
      tr a-z A-Z << END_TEXT
        one two three
        four five six
      END_TEXT      

Results in:

$ tr a-z A-Z << END_TEXT # collapsed multiline command
  ONE TWO THREE
  FOUR FIVE SIX

Add color codes to script output

Script output can be colored using ANSI escape codes, or by running commands or programs that output ANSI escape codes.

For example, using Bash with color codes:

job:
  script:
    - echo -e "\e[31mThis text is red,\e[0m but this text isn't\e[31m however this text is red again."

You can define the color codes in Shell variables, or even custom environment variables, which makes the commands easier to read and reusable.

For example, using the same example as above and variables defined in a before_script:

job:
  before_script:
    - TXT_RED="\e[31m" && TXT_CLEAR="\e[0m"
  script:
    - echo -e "${TXT_RED}This text is red,${TXT_CLEAR} but this part isn't${TXT_RED} however this part is again."
    - echo "This text is not colored"

Or with PowerShell color codes:

job:
  before_script:
    - $esc="$([char]27)"; $TXT_RED="$esc[31m"; $TXT_CLEAR="$esc[0m"
  script:
    - Write-Host $TXT_RED"This text is red,"$TXT_CLEAR" but this text isn't"$TXT_RED" however this text is red again."
    - Write-Host "This text is not colored"