From f7bb764909e42d807d3c9c59b439aec773a63554 Mon Sep 17 00:00:00 2001
From: Timothee Cour <timothee.cour2@gmail.com>
Date: Tue, 2 Jun 2020 00:46:51 -0700
Subject: [PATCH] fix https://github.com/timotheecour/Nim/issues/266 retry on
 failure to avoid common 503 github errors

---
 lib/std/private/nimbleutils.nim    | 32 ++++++++++++++++++++++++++++++
 testament/categories.nim           |  7 ++++---
 testament/lib/stdtest/netutils.nim |  4 ++++
 3 files changed, 40 insertions(+), 3 deletions(-)
 create mode 100644 lib/std/private/nimbleutils.nim

diff --git a/lib/std/private/nimbleutils.nim b/lib/std/private/nimbleutils.nim
new file mode 100644
index 0000000000000..297fb96958bbd
--- /dev/null
+++ b/lib/std/private/nimbleutils.nim
@@ -0,0 +1,32 @@
+##[
+internal API for now, API subject to change
+]##
+
+import std/[os,osproc,sugar,strutils]
+
+proc actionRetry*(maxRetry: int, backoffDuration: float, action: proc(): bool): bool =
+  ## retry `action` up to `maxRetry` times with exponential backoff and initial
+  ## duraton of `backoffDuration` seconds
+  var t = backoffDuration
+  for i in 0..<maxRetry:
+    if action(): return true
+    if i == maxRetry - 1: break
+    sleep(int(t * 1000))
+    t = t * 2 # exponential backoff
+  return false
+
+proc nimbleInstall*(name: string, message: var string): bool =
+  let cmd = "nimble install -y " & name
+  let (outp, status) = execCmdEx(cmd)
+  if status != 0:
+    message = "'$1' failed:\n$2" % [cmd, outp]
+    result = false
+  else: result = true
+
+when isMainModule:
+  block:
+    var msg: string
+    let ok = actionRetry(maxRetry = 2, backoffDuration = 0.1):
+      (proc(): bool = nimbleInstall("nonexistant", msg))
+    doAssert "Package not found" in msg
+    doAssert not ok
diff --git a/testament/categories.nim b/testament/categories.nim
index 114949ce8fe0e..88f1686088ddf 100644
--- a/testament/categories.nim
+++ b/testament/categories.nim
@@ -13,6 +13,7 @@
 # included from testament.nim
 
 import important_packages
+import std/private/nimbleutils
 
 const
   specialCategories = [
@@ -501,9 +502,9 @@ proc testNimblePackages(r: var TResults; cat: Category; packageFilter: string, p
       if not existsDir(buildPath):
         if hasDep:
           let installName = if url.len != 0: url else: name
-          let (nimbleCmdLine, nimbleOutput, nimbleStatus) = execCmdEx2("nimble", ["install", "-y", installName])
-          if nimbleStatus != QuitSuccess:
-            let message = "nimble install failed:\n$ " & nimbleCmdLine & "\n" & nimbleOutput
+          var message: string
+          if not actionRetry(maxRetry = 3, backoffDuration = 1.0,
+            (proc(): bool = nimbleInstall(installName, message))):
             r.addResult(test, targetC, "", message, reInstallFailed)
             continue
 
diff --git a/testament/lib/stdtest/netutils.nim b/testament/lib/stdtest/netutils.nim
index eb913a56a93f8..bbf140faeb21f 100644
--- a/testament/lib/stdtest/netutils.nim
+++ b/testament/lib/stdtest/netutils.nim
@@ -1,3 +1,7 @@
+##[
+internal API for now, API subject to change
+]##
+
 import std/[nativesockets, asyncdispatch, os]
 
 proc bindAvailablePort*(handle: SocketHandle, port = Port(0)): Port =