Added self-update command

install.sh

@@ -225,6 +225,9 @@ wasmer_install() {
   magenta2="${reset}\033[34m"
   magenta3="${reset}\033[34;2m"
 
+  if which wasmer >/dev/null; then
+    printf "${reset}Updating wasmer$reset\n"
+  else
     printf "${reset}Installing Wasmer!$reset\n"
     printf "
   ${magenta1}      ${magenta2}        ${magenta3}###${reset}                                 
@@ -245,6 +248,7 @@ wasmer_install() {
             ${magenta1}####${reset}                                    
 
 "
+  fi
 #   if [ -d "$HOME/.wasmer" ]; then
 #     if which wasmer; then
 #       local latest_url
@@ -290,9 +294,41 @@ wasmer_install() {
 
 
 wasmer_reset() {
-  unset -f wasmer_install wasmer_reset wasmer_download_json wasmer_link wasmer_detect_profile wasmer_download_file wasmer_download wasmer_verify_or_quit
+  unset -f wasmer_install wasmer_compareversions wasmer_reset wasmer_download_json wasmer_link wasmer_detect_profile wasmer_download_file wasmer_download wasmer_verify_or_quit
 }
 
+# Example taken from
+# https://stackoverflow.com/questions/4023830/how-to-compare-two-strings-in-dot-separated-version-format-in-bash
+wasmer_compareversions () {
+    if [[ $1 == $2 ]]
+    then
+        return 0
+    fi
+    local IFS=.
+    local i ver1=($1) ver2=($2)
+    # fill empty fields in ver1 with zeros
+    for ((i=${#ver1[@]}; i<${#ver2[@]}; i++))
+    do
+        ver1[i]=0
+    done
+    for ((i=0; i<${#ver1[@]}; i++))
+    do
+        if [[ -z ${ver2[i]} ]]
+        then
+            # fill empty fields in ver2 with zeros
+            ver2[i]=0
+        fi
+        if ((10#${ver1[i]} > 10#${ver2[i]}))
+        then
+            return 1
+        fi
+        if ((10#${ver1[i]} < 10#${ver2[i]}))
+        then
+            return 2
+        fi
+    done
+    return 0
+}
 
 wasmer_download() {
   # identify platform based on uname output
@@ -322,6 +358,25 @@ wasmer_download() {
       printf "\033[1A$cyan> Getting wasmer releases... ✓$reset\n"
   fi
 
+  if which wasmer >/dev/null; then
+    WASMER_VERSION=$(wasmer --version | sed 's/[a-z[:blank:]]//g')
+    wasmer_compareversions "$WASMER_VERSION" "$WASMER_RELEASE_TAG"
+    case $? in
+      # WASMER_VERSION = WASMER_RELEASE_TAG
+      0)
+        printf "You are already on the latest wasmer: ${WASMER_RELEASE_TAG}\n";
+        exit 0
+        ;;
+      # WASMER_VERSION > WASMER_RELEASE_TAG
+      1)
+        printf "You are already on a more recent version than the published one: ${WASMER_RELEASE_TAG}.\nExiting\n";
+        exit 0
+        ;;
+      # WASMER_VERSION < WASMER_RELEASE_TAG (we continue)
+      2)
+      ;;
+    esac
+  fi
   # fetch the real release data to make sure it exists before we attempt a download
   wasmer_download_json RELEASE_DATA "$RELEASES_URL/tag/$WASMER_RELEASE_TAG"
 

src/main.rs

@@ -29,6 +29,7 @@ mod macros;
 mod recovery;
 pub mod apis;
 pub mod common;
+mod update;
 pub mod sighandler;
 #[cfg(test)]
 mod spectests;
@@ -41,6 +42,10 @@ enum CLIOptions {
     /// Run a WebAssembly file. Formats accepted: wasm, wast
     #[structopt(name = "run")]
     Run(Run),
+
+    /// Update wasmer to the latest version
+    #[structopt(name = "self-update")]
+    SelfUpdate,
 }
 
 #[derive(Debug, StructOpt)]
@@ -117,5 +122,6 @@ fn main() {
     let options = CLIOptions::from_args();
     match options {
         CLIOptions::Run(options) => run(options),
+        CLIOptions::SelfUpdate => update::self_update(),
     }
 }

src/update.rs

@@ -0,0 +1,17 @@
+//! When wasmer self-update is executed, this is what gets executed
+use std::process::{Command, Stdio};
+use std::io;
+
+pub fn self_update() {
+    println!("Fetching latest installer");
+    let cmd = Command::new("curl").arg("https://get.wasmer.io").arg("-sSfL")
+            .stdout(Stdio::piped()).spawn().unwrap();
+
+    let mut the_process =  Command::new("sh")
+            .stdin(cmd.stdout.unwrap())
+            .stdout(Stdio::inherit())
+            .spawn()
+            .ok().expect("Failed to execute.");
+
+    the_process.wait();
+}