envsubst-recursive.sh

envsubst-recursive.sh

#!/usr/bin/env bash
# Usage envsubst-recursive.sh [source root]
# Options:
# -a|--append    - Set string to append to processed source file names
# -f|--filter    - Set the filename filter (only process files matching this filter)
# -o|--output    - Set the output directory for substituted file
# -q|--quiet     - Enable quiet mode, no script output
# -v|--variables - Set the variable names to replace only. IMPORTANT: Single quote this argument

# Script variable defaults
sourceRoot=""
outputRoot=""
replacementVariables=""
processedAppend=""
fileNameFilter=""
quietModeEnabled=1 #false

# Process CLI Arguments
positional=()
while [[ $# -gt 0 ]]
do
    case "$1" in
        -a|--append)
            processedAppend="$2"
            shift # past argument
	        shift # past value
        ;;
        -f|--filter)
            fileNameFilter="-name $2"
            shift # past argument
	        shift # past value
        ;;
        -o|--output)
            outputRoot="${2%/}"
            shift # past argument
	        shift # past value
        ;;
        -q|--quiet)
            quietModeEnabled=0 # true
            shift # past argument
        ;;
        -v|--variables)
            replacementVariables="$2"
            shift # past argument
            shift # past value
        ;;
        *)
            #Unhandled options treated as positional arguments
	   		positional+=("$1")
	    	shift # past argument
	    ;;
    esac
done
set -- "${positional[@]}" # restore positional parameters

# Grab the source root, trimming any trailing /
# Ensure not empty, error and exit if it is
# Create glob patterns for source root
sourceRoot=${1%/}
if [[ -z "$sourceRoot" ]]; then
    echo "Error: No source root defined"
    exit 1
fi
if [[ ! -d "$sourceRoot" ]]; then
    echo "Error: $sourceRoot not found"
    exit 1
fi
sourceGlob=($sourceRoot/**/*)

# If no output set via options, use the validated source root
if [[ -z "$outputRoot" ]]; then
    outputRoot="$sourceRoot"
fi

# Output start message if not in quiet mode
if [[ $quietModeEnabled -eq 1 ]]; then
    echo "Substituting environment variables"
fi

# Loop every directory
for file in $(find "$sourceRoot" -type f $fileNameFilter); do
    # Determine paths post processing
    sourcePath="$file$processedAppend"
    outputPath="${file/$sourceRoot/$outputRoot}"

    # If output root directory does not exist create it
    if [[ ! -d $(dirname "$outputPath") ]]; then
        mkdir -p $(dirname "$outputPath")
    fi

    # If file being processed and final source path different (ie has been appended to), move to location
    if [[ "$file" != "$sourcePath" ]]; then
        mv "$file" "$sourcePath"
    fi

    # Do the variable substitution
    if [[ -z "$replacementVariables" ]]; then
        envsubst < "$sourcePath" > $outputPath
    else
        envsubst "$replacementVariables" < "$sourcePath" > $outputPath
    fi

    # Output process record if not in quiet mode
    if [[ $quietModeEnabled -eq 1 ]]; then
        echo "Processed: $sourcePath -> $outputPath"
    fi
done

# Output end message if not in quiet mode
if [[ $quietModeEnabled -eq 1 ]]; then
    echo "Done"
fi