shellfu-bash-saturnin/src/saturnin.sh.skel

#!/bin/bash

shellfu import exit
shellfu import inigrep
shellfu import pretty

#
# Saturnin - __MKIT_PROJ_TAGLINE__
#
# Saturnin is a Shellfu module that can help you build consistent and easy
# to use command line-based toolkit.  The idea is that you have a set of
# scripts that together form a particular tool, which you then integrate
# under a single meta-command (similar to git, apt, systemctl and many
# others...).
#
# Saturnin's main goal is to help you with the integration so that you can
# fully concentrate on development of the scripts, while Saturnin will
# provide the common part of command-line interface.  Adding to that,
# Saturnin also provides several extra features as config management,
# hooks or support for command line completion.
#
# It's possible to integrate any kind of programs within Saturnin, although
# extra features are currently only available for Shellfu/Bash scripts.
#
# Starting your toolkit
# =====================
#
# The starting point of a Saturnin-powered toolkit is the main meta-command,
# which sets all mandatory variables and calls saturnin__main().  You could
# implement that one yourself, but it's **strongly recommended** to start
# off by creating a copy of 'app.skel' from 'saturnin-demo':
#
#     https://github.com/AloisMahdal/saturnin-demo/
#
# In fact, it's best to actually copy the *whole* project, which serves
# as skeleton of not just the meta-command (by Saturnin) but also MKit
# install/build system, which provides features like installation
# scripts, SemVer-compatible versioning and packaging templates for both
# RPM and DEB:
#
#     git clone https://github.com/AloisMahdal/saturnin-demo
#     mv saturnin-demo myproject
#     cd myproject
#     rm -rf .git
#     git init
#
# You will need to edit few files, for starters:
#
#     edit mkit.ini                     # your main project info
#     edit packaging/template.spec      # file lists, Requires and description
#     edit packaging/debian/control     # ..also for Debian
#     git add .
#     git commit -m "Initial commit"
#
# ...but the reward is sweet:
#
#     make install      # to install to current system
#
#     make rpmstuff     # to get .spec file and source tarball
#     make debstuff     # to get debian directory
#     make vbump        # to seal off release
#     make release      # to seal off release
#

#
# Git commit hash of application source tree
#
# This is supposed to be set by your build scripts when building your
# application.  The string is returned by calling your meta-command with
# option --saturnin-app-git-hash.
#
# Look for 'satcmd' template for a working example.
#
SATURNIN_APP_GIT_HASH=${SATURNIN_APP_GIT_HASH:-}

#
# Your application version
#
# This is supposed to be set by your build scripts when building your
# application.  The string is returned by calling your meta-command with
# options --version, --version-semver or  --saturnin-app-version.
#
# Look for 'satcmd' template for a working example.
#
SATURNIN_APP_VERSION=${SATURNIN_APP_VERSION:-}

#
# Path to user cache
#
SATURNIN_CACHE_HOME=${SATURNIN_CACHE_HOME:-}

#
# Path where saturnin__conf should look for files
#
# If filename does not contain slash, it is looked up in each (or all,
# based on strategy--see saturnin__conf() doc) path in this list. The
# list is colon-separated and non-dirs as well as empty strings are
# silently ignored.
#
SATURNIN_CONF_PATH="${SATURNIN_CONF_PATH:-}"

#
# Expected config filename extension (for guessing from path head)
#
# If no filename to read is given, saturnin__conf() will guess filename
# as the path head plus this suffix (e.g. `foo.ini` for `saturnin__conf
# foo.bar.baz`)
#
SATURNIN_CONF_SUFFIX="${SATURNIN_CONF_SUFFIX:-.ini}"

#
# Directory where to look for subcommands
#
# Files here starting with $SATURNIN_LIBEXEC_PREFIX are considered
# subcommands
#
SATURNIN_LIBEXEC="${SATURNIN_LIBEXEC:-}"

#
# Subcommand file prefix
#
# This is recommended to be set to meta-command name plus dash.  For
# example, if your meta-command is `mykit`, this should be set to
# `mykit-`.
#
SATURNIN_LIBEXEC_PREFIX="${SATURNIN_LIBEXEC_PREFIX:-}"

#
# Meta-command help mode
#
# This controls what is displayed when user calls meta-command with --help
# argument.  Following formats are supported:
#
#     +HELPFILE
#     =HELPFILE
#
# In both cases, HELPFILE must be absolute path to a file containing
# human-readable description of the meta-command, which will be directly
# presented to user.
#
# If the leading character is '=' (equal sign), the help text consists of,
# and only of the HELPFILE.  If the character is '+' (plus sign), the help
# text is pre-pended with auto-generated usage message.
#
# If the value is empty, only the auto-generated usage message is printed.
#
SATURNIN_META_HELP="${SATURNIN_META_HELP:-}"

#
# Current running subcommand
#
# The value is set and exported into sub-command binary at moment of
# saturnin__main() call.Z
#
SATURNIN_SUBCOMMAND="${SATURNIN_SUBCOMMAND:-}"

saturnin__bug() {
    #
    # Warn about bug in your software
    #
    # Issue warning using warn() from pretty but also add application
    # version.  This is useful when an assertion in your application fails
    # such that it is certain that there is a bug inside it.
    #
    # In such cases, it makes sense to print also version information to
    # help users with reporting.
    #
    local msg           # message core
    for msg in "$@";
    do
        warn "bug: $msg"
    done
    warn "bug in $(basename "$0") version: $SATURNIN_APP_VERSION"
}

saturnin__conf() {
    #
    # inigrep smart loader
    #
    # Usage:
    #   saturnin__conf [-j] [inigrep-query] [-- [file]..]
    #
    #
    # File arguments
    # ==============
    #
    # If omitted, *file* argument is inferred by taking part of kpath name
    # before first dot and appending value of `$SATURNIN_CONF_SUFFIX`,
    # (".ini" by default).
    #
    # Each *file* argument is then processed as follows:
    #
    #  *  `-` (single dash) is interpreted as reading from standard input.
    #
    #  *  If argument contains slash, it is expanded as a regular path
    #     (relative or absolute).
    #
    #  *  Otherwise, it is taken as filename and searched for in directories
    #     given in `$SATURNIN_CONF_PATH`.  (This can yield more than one
    #     path, which is equivalent as if all paths were provided.)
    #
    #     Not all files expanded based on `$SATURNIN_CONF_PATH` are read by
    #     default; reading is governed by "merge strategy": the default
    #     strategy "first" reads only the first existing file.
    #
    #     "join" strategy on the other hand, means that any files are simply
    #     concatenated and prefixed with comment (visible only in raw mode)
    #     containing path to the file.
    #
    #     This means that if a section is queried that is present in both
    #     files, it is effectively concatenated as well.
    #
    # Following calls are equivalent
    #
    #     saturnin__conf foo.bar.baz
    #     saturnin__conf foo.bar.baz foo.ini
    #
    # and both result in reading of key *baz* from section *foo.bar* in file
    # *foo.ini*, which is selected from *SATURNIN_CONF_PATH*.  Should there
    # be more foo.ini's, the first is selected.  Using `-j` switch
    #
    #     saturnin__conf -j foo.bar.baz
    #
    # would cause all foo.ini's on *SATURNIN_CONF_PATH* be concatenated
    # instead.
    #
    local ig_mode               # retrieval mode
    local ig_query              # keypath or section name (when listing keys)
    local ig_limit              # line limit
    local files=()              # file specification
    local Strategy=first        # merge strategy
    while true; do case $1:$2 in
        "":*)   break ;;
        -j:*)   Strategy=join;           shift 1        ;;
        -1:*)   ig_limit=$1;             shift 1        ;;
        -e:*.*) ig_mode=$1; ig_query=$2; shift 2; break ;;
        -r:*.*) ig_mode=$1; ig_query=$2; shift 2; break ;;
        -K:*)   ig_mode=$1; ig_query=$2; shift 2; break ;;
        -S:*)   ig_mode=$1; ig_query=""; shift 1; break ;;
        -P:*)   ig_mode=$1; ig_query=""; shift 1; break ;;
        .*:*)   _saturnin__conf_usage -w "bad syntax: $*" ;;
        *.*:*)  ig_mode=-e; ig_query=$1; shift 1; break ;;
        --help:*) _saturnin__conf_usage -e 0            ;;
        *)      _saturnin__conf_usage -w "bad syntax: $*" ;;
    esac done
    test -n "$ig_mode" || _saturnin__conf_usage -w "could not determine inigrep mode"
    debug -v ig_limit ig_query ig_mode Strategy
    if test -n "$*";
    then
        files=("$@")
    elif test -n "$ig_query";
    then
        files=("${ig_query%%.*}$SATURNIN_CONF_SUFFIX")
    else
        _saturnin__conf_usage -w "dunno what to load"
    fi
    debug -v files
    #shellcheck disable=SC2086
    _saturnin__conf__load "${files[@]}" | inigrep $ig_limit $ig_mode "$ig_query"
    return "${PIPESTATUS[0]}"
}

saturnin__conf_find() {
    #
    # Find all existing instances of sub-path $1 on $SATURNIN_CONF_PATH
    #
    # Usage:
    #
    #     saturnin__conf_find SUBPATH
    #
    # Go through all elements of $SATURNIN_CONF_PATH, looking for file or
    # directory, whose path is formed by joining SUBPATH to element of
    # $SATURNIN_CONF_PATH.  Print each existing path, ignore rest.
    #
    # For example, with following setup:
    #
    #     SATURNIN_CONF_PATH=foo:bar:baz
    #     mkdir -p foo/one bar/one
    #     mkdir -p bar/two/slashes
    #
    # call
    #
    #     saturnin__conf_find one
    #
    # would print `foo/one` and `bar/one`, while
    #
    #     saturnin__conf_find two/slashes
    #
    # would print `bar/two/slashes`.
    #
    # If at least one path was found, return zero.  Otherwise, return one,
    # or more in case of error.
    #
    local file=$1       # sub-path to find
    local trydir        # each item of $SATURNIN_CONF_PATH
    local trypath       # each combined path
    debug -v SATURNIN_CONF_PATH
    echos "$SATURNIN_CONF_PATH" \
      | tr ':' '\n' \
      | while read -r trydir;
        do
            test -n "$trydir" || continue
            trypath="$trydir/$file"
            test -e "$trypath" || continue
            echos "$trypath"
        done \
      | grep .
}

saturnin__get() {
    #
    # Show Saturnin internal info by key $1 and exit
    #
    # Key $1 can be whole `--saturnin-get-stuff` argument or just the part
    # after `--saturnin-get-`.
    #
    # This is aimed to help debugging and testing the app (or Saturnin
    # itself) by showing packaging and deployment related info.
    #
    local key=${1#--saturnin-get-}      # internal info key
    case "$key" in
        saturnin-conf-path) echo "$SATURNIN_CONF_PATH"      ;;
        saturnin-version)   echo "__MKIT_PROJ_VERSION__"    ;;
        app-git-hash)   echo "$SATURNIN_APP_GIT_HASH"       ;;
        app-version)    echo "$SATURNIN_APP_VERSION"        ;;
        cache-home)     echo "$SATURNIN_CACHE_HOME"         ;;
        libexec)        echo "$SATURNIN_LIBEXEC"            ;;
        libexec-prefix) echo "$SATURNIN_LIBEXEC_PREFIX"     ;;
        subcommands)    saturnin__lssc                      ;;
        *)              warn "unknown devel key: $key"
                        exit "$EXIT_USAGE" ;;
    esac
    exit "$EXIT_OK"
}

saturnin__lssc() {
    #
    # List subcommands
    #
    find "$SATURNIN_LIBEXEC" \
        -mindepth 1 \
        -maxdepth 1 \
        -executable \
        -name "$SATURNIN_LIBEXEC_PREFIX*" \
      | sed -e "s|^.*/||; s|^$SATURNIN_LIBEXEC_PREFIX||" \
      | sort
}

saturnin__main() {
    #
    # Main meta-command entry function
    #
    # After setting all mandatory environment variables, call this from your
    # main meta-command script.
    #
    local subcommand    # subcommand to execute (first non-option)
    test -n "$SATURNIN_CACHE_HOME"     || die "SATURNIN_CACHE_HOME is not set"
    test -n "$SATURNIN_LIBEXEC"        || die "SATURNIN_LIBEXEC is not set"
    test -n "$SATURNIN_LIBEXEC_PREFIX" || die "SATURNIN_LIBEXEC_PREFIX is not set"
    while true; do case $1 in
        -D|--full-debug) export PRETTY_DEBUG=true
                        export PRETTY_DEBUG_EXCLUDE=""
                                                    shift ;;
        -d|--debug)     export PRETTY_DEBUG=true;   shift ;;
        -v|--verbose)   export PRETTY_VERBOSE=true; shift ;;
        -h|--help)      saturnin__help;             exit  ;;
        --version)      saturnin__version;          exit  ;;
        -V|--version-semver) saturnin__get app-version ;;
        --saturnin-get-*) saturnin__get "$1"        ;;
        -*)             saturnin__usage -w "unknown argument: $1" ;;
        --*)            saturnin__usage -w "unknown argument: $1" ;;
        --)             shift; break                ;;
        "")             saturnin__usage -w "too few arguments" ;;
        *)              break;                      ;;
    esac done
    subcommand="$1"; shift
    PRETTY_DEBUG_EXCLUDE="" debug -v SATURNIN_APP_VERSION BASH_VERSION
    debug -v SATURNIN_CONF_PATH
    case "$subcommand" in
        conf)    saturnin__conf "$@"                ;;
        *)       saturnin__runsc "$subcommand" "$@" ;;
    esac
}

saturnin__help() {
    #
    # Print meta-command help text
    #
    # See $SATURNIN_META_HELP for details.
    #
    local introline     # introduction line
    introline=$(basename "$0")
    test -n "$SATURNIN_APP_TAGLINE" \
     && introline+=" - $SATURNIN_APP_TAGLINE"
    case "$SATURNIN_META_HELP" in
        "")
            echo "$introline"$'\n' >&2
            saturnin__usage -E -e 0
            ;;
        +/*)
            echo "$introline"$'\n' >&2
            saturnin__usage -E
            echo >&2
            _saturnin__cat_helpfile "${SATURNIN_META_HELP:1}"
            ;;
        =/*)
            _saturnin__cat_helpfile "${SATURNIN_META_HELP:1}"
            ;;
        *)
            echo "$introline"$'\n' >&2
            saturnin__usage -E
            saturnin__bug "malformed SATURNIN_META_HELP: $SATURNIN_META_HELP"
            return 3
            ;;
    esac
}

saturnin__conf_mkpath() {
    #
    # Compose new value for $SATURNIN_CONF_PATH from locations $@
    #
    # Usage:
    #
    #     saturnin__conf_mkpath DIR [DIR..]
    #
    # Go through each DIR and print it, unless it ends with "/ini.d",
    # in which case list its subdirectories, sorted by C locale (this allows
    # for modular configuration).
    #
    # Non-existent or non-directory items are silently ignored.
    #
    local location      # one location argument
    local path          # one path listed
    for location in "$@";
    do
        test -d "$location" || continue
        case "$location" in
            */ini.d)    # modular location--sort subfolders
                find -L "$location" -mindepth 1 -maxdepth 1 -type d \
                  | LC_ALL=C sort
                ;;
            *)
                echo "$location"
                ;;
        esac
    done \
      | _saturnin__nl2colon
}

saturnin__runhook() {
    #
    # Run custom hook named $1 from respective configuration section
    #
    # Will load joined multi-line key "hook.$SATURNIN_SUBCOMMAND.$1" and
    # unless syntax check fails, execute it as Bash code (in separate
    # process).
    #
    local name="$1"     # hook name
    local code          # ... code
    test -n "$SATURNIN_SUBCOMMAND" || {
        warn "unknown subcommand, ignoring hook: $name"
        return 0
    }
    code="$(saturnin__conf -j "hook.$SATURNIN_SUBCOMMAND.$name")"
    debug -v SATURNIN_SUBCOMMAND code name
    bash -n <<<"$code" || {
        warn "syntax errors, ignoring hook: $name"
        return 0
    }
    bash <<<"$code"
}

saturnin__runsc() {
    #
    # Run subcommand $1 with arguments $2..
    #
    local subcommand="$1"; shift    # subcommand to run
    local binpath                   # path to subcommand's binary
    binpath+="$SATURNIN_LIBEXEC/"
    binpath+="$SATURNIN_LIBEXEC_PREFIX$subcommand"
    debug -v binpath
    debug "\$*='$*'"
    test -x "$binpath" \
     || saturnin__usage "invalid sub-command: $subcommand"
    SATURNIN_SUBCOMMAND="$subcommand" "$binpath" "$@"
}

saturnin__usage() {
    #
    # Show usage message and exit
    #
    #shellcheck disable=SC2046
    mkusage "$@"                                            \
            "[options] COMMAND [ARG...]"                    \
        -o                                                  \
            "-D, --full-debug   turn on gory debugging"     \
            "-V, --version  show version and exit"          \
            "-d, --debug    turn on debugging"              \
            "-h, --help     show this help message and exit"\
            "-v, --verbose  turn on verbosity"              \
        -c                                                  \
            $(saturnin__lssc)
}

saturnin__version() {
    #
    # Print human-readable version info
    #
    # Basic version info is already stored in $SATURNIN_APP_VERSION,
    # this function prints more descriptive paragraph including Saturnin's
    # own version.
    #
    echo -n "$(basename "$0")"
    test -n "$SATURNIN_APP_TAGLINE" \
     && echo -n " ($SATURNIN_APP_TAGLINE)"
    echo -n " $SATURNIN_APP_VERSION"
    test -n "$SATURNIN_APP_CODENAME" \
     && echo -n " - $SATURNIN_APP_CODENAME"
    echo
    echo -n "Powered by Saturnin (__MKIT_PROJ_TAGLINE__)"
    echo -n " __MKIT_PROJ_VERSION__"
    echo -n " - __MKIT_PROJ_CODENAME__"
    echo
    return "$EXIT_OK"
}

saturnin__wraphook() {
    #
    # Wrap command $@ in hooks 'pre' and 'post'
    #
    # Run pre hook, then command $@, then post hook.  Always exit with
    # status of the payload command, even if hooks fail.  Ignore post-hook
    # if payload command failed.
    #
    local es=0      # exit status of this function
    saturnin__runhook pre
    "$@" || return $?
    es=$?
    saturnin__runhook post
    return $es
}


#          #                           that what you see below this line #
# INTERNAL # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ #
#          #                        use in your code to anger the divine #

_saturnin__cat_helpfile() {
    #
    # Print helpfile $1
    #
    local helpfile=$1   # path to help file
    cat "$helpfile" >&2 && return 0
    saturnin__bug "cannot print help file: $helpfile"
    return 3
}

_saturnin__conf__merge() {
    #
    # Take paths and applying merge strategy, load file(s)
    #
    local path          # every path
    local found=false   # 'true' if we got any path
    while read -r path;
    do
        found=true
        case $Strategy in
            first)
                debug "winner: $path"
                cat "$path"
                cat >/dev/null  # throw away rest of paths
                ;;
            join)
                echo "# file: ${path/$HOME/~}"
                cat "$path" 2>/dev/null
                ;;
        esac
    done
    $found
}

_saturnin__conf__load() {
    #
    # Print contents of files specified in $@
    #
    # Each argument means possible file candidate.  If candidate contains
    # slash, it's treated as file path and is printed directly.  If it's
    # single dash, standard input is copied.
    #
    # In all other cases, filename is searched in all elements of variable
    # SATURNIN_CONF_PATH; output then depends on chosen $Strategy: with
    # 'first' strategy, first existing file is printed, with 'join'
    # strategy, all existing files are printed.
    #
    local arg       # each passed argument
    local es=0      # exit status of this function
    for arg in "$@";
    do
        case $arg in
            -|*/*)      # stdin, or path (with slash)
                cat "$arg" || es=3
                ;;
            *)          # name given, find all its incarnations
                saturnin__conf_find "$arg" \
                  | _saturnin__conf__merge; es=$?
                ;;
        esac
    done
    return $es
}

_saturnin__conf_usage() {
    #
    # Show usage message, passing $@ to mkusage() and exit
    #
    PRETTY_USAGE="self=${0##*/} conf" \
    mkusage "$@"                                                              \
            "[options] [-e] SECTION.KEY [FNAME]"                              \
            "[options] -r SECTION.KEY [FNAME]"                                \
            "[options] -K SECTION [FNAME]"                                    \
            "[options] -P FNAME"                                              \
            "[options] -S FNAME"                                              \
        --                                                                    \
            "Use inigrep to query config files."                              \
        -o                                                                    \
            "-j     join all files before applying query"                     \
            "-1     ensure single line is returned"                           \
        -c                                                                    \
            "-e     use normal mode (default)"                                \
            "-r     use raw mode (preserves RHS whitespace and some comments)"\
            "-K     list available keys in SECTION"                           \
            "-S     list available sections in FNAME"                         \
            "-P     list available keypaths (SECTION.KEY) in FNAME"           \
        --                                                                    \
            "FNAME is filename, which is then searched on all paths specified"\
            "in SATURNIN_CONF_PATH and depending on -j parameter, first one"  \
            "wins or all are joined.  If FNAME contains slash, this search is"\
            "not done and FNAME is taken as path to file that is then"        \
            "queried."                                                        \
            ""                                                                \
            "If FNAME is omitted, it is inferred from SECTION (e.g. 'foo.ini'"\
            "if 'foo.bar' was section name; note that section name itself may"\
            "contain dot)."
}

_saturnin__nl2colon() {
    #
    # Convert newline-based list of paths to colon:based:list
    #
    # Empty paths must not be included in the resulting list, so we need to
    # drop them and also get the colons right.
    #
    local idx=0     # current item index (zero-based)
    local path      # each path on stdin
    while read -r path;
    do
        test -z "$path" && continue
        test $idx -gt 0 && echo -n ':'
        echo -n "$path"
        ((idx++))
    done
}

#shellfu module-version=__MKIT_PROJ_VERSION__