Add retry to .sh script

Author: bekir-ozturk

src/dotnet-install.sh

@@ -744,13 +744,29 @@ download() {
     fi
 
     local failed=false
-    if machine_has "curl"; then
-        downloadcurl "$remote_path" "$out_path" || failed=true
-    elif machine_has "wget"; then
-        downloadwget "$remote_path" "$out_path" || failed=true
-    else
-        failed=true
-    fi
+    local attempts=0
+    while [ $attempts -lt 3 ]; do
+        attempts=$((attempts+1))
+        failed=false
+        if machine_has "curl"; then
+            downloadcurl "$remote_path" "$out_path" || failed=true
+        elif machine_has "wget"; then
+            downloadwget "$remote_path" "$out_path" || failed=true
+        else
+            failed = true
+        fi
+
+        if [ "$failed" = false ] || [ $attempts -ge 3 ] || { [ ! -z $http_code ] && [ $http_code = "404" ]; }; then
+            break
+        fi
+
+
+        say "Trying for the $((attempts+1))rd time in $((attempts*10)) seconds."
+        sleep $((attempts*20))
+    done
+
+
+
     if [ "$failed" = true ]; then
         say_verbose "Download failed: $remote_path"
         return 1
@@ -761,6 +777,8 @@ download() {
 # Updates global variables $http_code and $download_error_msg
 downloadcurl() {
     eval $invocation
+    unset http_code
+    unset download_error_msg
     local remote_path="$1"
     local out_path="${2:-}"
     # Append feed_credential as late as possible before calling curl to avoid logging feed_credential
@@ -789,6 +807,8 @@ downloadcurl() {
 # Updates global variables $http_code and $download_error_msg
 downloadwget() {
     eval $invocation
+    unset http_code
+    unset download_error_msg
     local remote_path="$1"
     local out_path="${2:-}"
     # Append feed_credential as late as possible before calling wget to avoid logging feed_credential
@@ -882,7 +902,6 @@ install_dotnet() {
     say "Downloading primary link $download_link"
 
     # The download function will set variables $http_code and $download_error_msg in case of failure.
-    http_code=""; download_error_msg=""
     download "$download_link" "$zip_path" 2>&1 || download_failed=true
     primary_path_http_code="$http_code"; primary_path_download_error_msg="$download_error_msg"
 
@@ -906,7 +925,6 @@ install_dotnet() {
             say "Downloading legacy link $download_link"
 
             # The download function will set variables $http_code and $download_error_msg in case of failure.
-            http_code=""; download_error_msg=""
             download "$download_link" "$zip_path" 2>&1 || download_failed=true
             legacy_path_http_code="$http_code";  legacy_path_download_error_msg="$download_error_msg"