Add version_manager for inexorCore versions

[a-teammate]

Currently we have the instancemanager, which is responsible for starting inexorcore instances. We furthermore have the first approach to download InexorCore in InexorFlex from GitHub (#440). Whats missing is a system which tries to do more than "get the one binary folder from GitHub, replace the old one". And its needed; currently all our wikis are broken because make install && cd flex && npm start won't bring you anywhere, as there is no real organisation of the binary dir - an environment var is needed to be set every time before that (or globally) to point to the binary dir you want to start -.

What should this system do?

First of all is the goal to have one (or more, see add_remote) folder for all inexor-core packages (each of them with a bin/ subfolder with included binaries according to #430)

• list_versions(bool local)
  • list all (locally) available inexor-core binary folders
• add_remote(type, url)
  • add a storage where one can find a package with a "bin" subfolder
    • hence a version of inexorcore
  • type is one of LOCAL, FTP, GITHUB or GIT
• get_exact_version_name(semversion_string, remote=all)
  • should allow semversion stuff like "^0.1.2"
  • returns the exact version name
  • allows also names like "a_teammate_little_fix_branch"
    • this way we can just rename the "build" folder, devs build into
  • remote filter could be used to only allow updates from inexor-cores github releases page
• get_version(exact_version_name, bool should_download=false)
  • semversion_string can be available locally or just on a remote
  • if only on remote, we download it according to the flag
• get_local_path(exact_version_name)
  • returns the path to the binary folder on your harddisk

whats missing in here is metainfo bundled with the inexorcore versions: e.g. a specific core version is not ultimately compatible with a media or flex version. but i think that's another improvement for later

---

IMHO we should include this to the 0.9 milestone, as this is currently something broken (in my eyes - since I can't tell new devs how to setup their toolset and others do not provide clear instructions to them either. so why not fix this instead of telling them the nasty workaround?)

[Fohlen]

This needs #430 in order to work

[Fohlen]

Also I disagree with adding this to the milestone. Let's don't blow this up. Nearly zero commits have been going to Inexor during August and we want to add stuff on top? I dislike that idea.

[a-teammate]

This is actually a solution for #419 which exists in the issue tracker for ages. why not add it now? its not too much work and fills exactly the whole we (or more precisely the inexor-core devs) have atm.

I made a pseudocode draft this morning. (pseudo since im a js noob and this is neither tested, nor has the full functionality done)

const fs = require('fs');
const semver = require('semver');

/*
* This is the class responsible for handling different versions of inexor-core.
* It can add different remotes (locally and really on another server).
* If the version is not locally available it can download it from GITHUB/releases or from a prepared server with inexor-core-archives.
* It downloads it to the first remote of type REMOTE_TYPE.LOCAL.
* It reacts on semantic version strings see https://github.com/npm/node-semver
* Note: We do not perform any checks whether the version is really correct (i.e. has a bin subfolder with binaries named correctly). maybe just yet?
* TODO: cache results, async checks?
*/
class VersionManager
{
    const REMOTE_TYPE = {
        LOCAL : 0,  // You can add various local directories, it assumes all subfolders to be versions.
        URL : 1,    // A Server can provide a json with a "os/arch/versions" array field. The remote then points to the json file on the server.
        GITHUB : 2  // A github repository e.g. https://github.com/inexorgame/inexor-core we assume all release folders
    };

    /*   Remotes:
    *    remotes is a map with 3 fields remotes[REMOTE_TYPE.LOCAL], remotes[REMOTE_TYPE.URL], remotes[REMOTE_TYPE.GITHUB],
    *    each of these fields is a list of strings.
    */

    /*
    * list all locally and remotely available inexor-core versions
    * returns a list of objects with .name and .remote_type and .path
    * what is a version? (local: subfolders, url: a field in a json, github: the answer of a GET request for releases)
    */
    list_versions() {
        let versions = _list_local_versions();
        versions += _list_url_versions();
        versions += _list_github_versions();
        // todo: wait here if we do it async?
        return versions;
    }

    /*
    * add a storage where one can find a package with a "bin" subfolder
    * hence a version of inexorcore
    * type is one of REMOTE_TYPE.LOCAL, REMOTE_TYPE.URL or REMOTE_TYPE.GITHUB
    * if insert is true, we add it at the beginning of the list
    */
    add_remote(type, path, insert=false) {
        if(type != REMOTE_TYPE.LOCAL && type != REMOTE_TYPE.URL && type != REMOTE_TYPE.GITHUB)
            /*TODO echo error this is not a valid REMOTE_TYPE*/;
        if(!insert)
            this.remotes[type] += [path];       // ????
        else
            this.remotes[type].insert(0, path); // ???? sth like that probably
    }

    /*
    * Gives back an object of a version fulfilling the semversion (the best).
    * Allows semversion stuff like "^0.1.2", see https://github.com/npm/node-semver.
    * returns a node with .name and .remote_type and .path
    * allows also names like "a_teammate_little_fix_branch"
    * this way we can just rename the "build" folder in which devs build into.
    */
    get_exact_version(semversion_string, nodownload = false) {
        let out = { name:"", remote_type:-1, path:"" };
        for(let version in (nodownload ? _list_local_versions() : list_versions()))
                if out.name is not set
                //    if semversion fulfilled: set out
                // if out.name is set:
                if(semver.satisfies(version.name, semversion_string))
                {
                    if(out.name == "") // first entry
                        out = version;
                    else // out is already set
                    {
                        if(semver.gt(out.name, version.name)                                    // better fulfills semversion (i.e. newer version)
                            || (semver.eq(version.name, out.name) && version.type == REMOTE_TYPE.LOCAL)) // already downloaded
                            out = version;
                    }
                }
        return out;
    }

    /*
    * semversion_string can be available locally or just on a non-local remote.
    * if only on non-local remote, we download it according to the flag
    * @returns the path to the binary folder on your harddisk.
    */
    aquire_version(semversion_string, nodownload = false) {
        const version = get_exact_version_name(semversion_string, nodownload);
        if(version.name == "")
            /* error no version found */;
        switch(version.remote_type)
        {
            case REMOTE_TYPE.LOCAL:
                return version.path;
            case REMOTE_TYPE.URL:
            case REMOTE_TYPE.GITHUB:
                // pseudocode:

                const first_local_remote = remotes[REMOTE_TYPE.LOCAL][0];
                // TODO: check if we have a local remote
                // const download_folder = first_local_remote; // i.e. "C://inexor/inexor-core-versions"
                // const temparchivefile = tempfolder + version.name;
                // const output_folder = download_folder + version.name; // i.e. C://inexor/inexor-core-versions/0.9.2-alpha
                // download(version.path, temparchivefile).then(
                //    decompress(temparchivefile, output_folder)
                // });
                return downloaded_folder;
        }
    }

    /*
    * list all locally available inexor-core binary folders
    * returns a list of nodes with .name, .remote_type and .path
    * TODO: make that object maybe a class?
    */
    _list_local_versions() {
        // for(let remote in this.remotes[REMOTE_TYPE.LOCAL])
            // check if remote is a directory
            // if yes: returns list of subfolders
            // optional maybe check for validity of the folder
    }

    /*
    * list all files in a specific remotely available url.
    * returns a list of nodes with .name, .remote_type and .path
    */
    _list_url_versions() {
        // for(let remote in this.remotes[REMOTE_TYPE.URL])
            // download json at the remote url
            // extract the correct "os/arch/versions" array field
    }

    /*
    * list all files in a specific remotely available url.
    * returns a list of nodes with .name, .remote_type and .path
    */
    _list_github_versions() {
        // for(let remote in this.remotes[REMOTE_TYPE.GITHUB])
            // use github api to check for versions for our os and arch.
    }
}

module.exports = VersionManager;

I understand that we still need to

• [ ] add the functionality to download
• [ ] add the functionality to list github versions
• [ ] add a switch for the arch maybe?
• [ ] test it (i've no real clue how lists and maps work in js)
• [ ] couple it with the instance-manager
• [ ] add a page which lists all versions in the ui-flex

[Fohlen]

This will at least require some serious changes on the instances code base to handle different binary types, I think

[a-teammate]

"to handle different binary types"? plz elaborate

The instance manager has a version_name field, e.g. "0.8.1". It asks the version manager for the bin folder of "0.8.1". It gets the bin folder. It starts the stuff in there. (Or e.g. `""` for the latest version)*

[a-teammate]

This is done with the providers of the ReleaseManager