win-service-updater

README

win-service-updater

Implementation of "core" wyUpdate functionality. wyUpdate is a utility written in C# for updating Windows applications. We used wyUpdate dependably for years, but couldn't rely on a standard version of .NET across our customer install base. Ultimately we decided to reimplement the wyUpdate functionality we used in GoLang.

Goals

• Support for TLS1.3 (default with GoLang 1.13 and main reason for creating this updater)
• Drop in replacement for use in existing service update commands (should work for any update, there is just no GUI)
• Compatibility with existing wyUpdate binary files

Features Implemented

Basic update functionality works.

• Check for update only (/justcheck /quickcheck arguments)
• Replacement of %urlargs% in URLs when -urlargs argument is provided
• Update file signature verification
• Full file update with ability to stop/start services before/after the update
• Rollback on failure
• Logging (-logging and /outputinfo arguments)

Current Limitations/Differences

• Support only for A.B.C.D (or A.B.C) version numbering; No "alpha", "beta", "pre", etc.
• No GUI component, created to be run from a service or command-line
• Only full binary replacement (no diff)
• Only supports stopping/starting services before/after update
  • No registry updates, COM updates, etc.
• No functionality to elevate privileges (need admin to install a service anyway)
• Only "installs" files to the "base directory" (directory the updater is run from)
• No FTP support
• Does not self-update
• No uninstall

Arguments supported

• "/debug"
• "/quickcheck"
• "/justcheck"
• "/noerr",
• "-urlargs=args"
• "/outputinfo=out"
• "/fromservice" (normal operation, but added so the argument parser doesn't error)
• "-logfile=log"
• "-cdata=file"
• "-wysserver=url"
• "-wyuserver=url"

Commands

• Run go build in cmd/updater for main updater executable
  • Run go generate first to embed version info into .exe (requires you to go install github.com/josephspurrier/goversioninfo/cmd/goversioninfo@latest)
• Run go build in cmd/wycparser for WYC parser executable (specifically the iuclient.iuc inside the archive)
• Run go build in cmd/wysparser for WYS parser executable
• Run go build in cmd/wyuparser for WYU parser executable (specifically the updtdetails.udt inside the archive)

General Operation

• To check if an update is available:
  • Download the .wys file (URL specified in client.wyc)
  • Compare the available update (specified in the .wys file) with the version currently installed
• If an update is required:
  • Download the .wyu file (URL specified in the .wys file)
  • If the update is signed, verify the signature of the update otherwise verify the checksum
  • Apply the update
  • Update the version number contained within the client.wyc