Fixes #138 #158. Pull image before building image (#159)

* Fixes #138 #158. Pull image before building image

This commit fixes error in case of e.g. Fedora registry is not
accessible for temporary reason like HTTP 503.
Second pulling should work usually.

Signed-off-by: Petr "Stone" Hracek <phracek@redhat.com>

* Check if docker image is not already pulled.

Signed-off-by: Petr "Stone" Hracek <phracek@redhat.com>

* remove duplicate code and check docker images for already pulled image

Signed-off-by: Petr "Stone" Hracek <phracek@redhat.com>

* Move image_name definition and check if equals to scratch

Signed-off-by: Petr "Stone" Hracek <phracek@redhat.com>

build.sh

@@ -76,6 +76,39 @@ function clean_image {
   fi
 }
 
+# Pull image based on FROM, before we build our own.
+function pull_image {
+  local dockerfile="$1"
+
+  # Get image_name from Dockerfile before pulling.
+  while read -r line; do
+    if ! grep -q "^FROM" <<< "$line"; then
+      continue
+    fi
+
+    image_name=$(echo "$line" | cut -d ' ' -f2)
+
+    # In case FROM scratch is defined, skip it
+    if [[ x"$image_name" == "xscratch" ]]; then
+      continue
+    fi
+    echo "-> Pulling image $image_name before building image from $dockerfile."
+    # Sometimes in Fedora case it fails with HTTP 50X
+    # Check if the image is available locally and try to pull it if it is not
+    if [[ "$(docker images -q "$image_name" 2>/dev/null)" != "" ]]; then
+      echo "The image $image_name is already pulled."
+      continue
+    fi
+    # Try pulling the image to see if it is accessible
+    if ! docker pull "$image_name"; then
+      echo "Pulling image $image_name failed. Let's wait 2 seconds and try one more time."
+      sleep 2
+      docker pull "$image_name"
+    fi
+
+  done < "$dockerfile"
+}
+
 # Perform docker build but append the LABEL with GIT commit id at the end
 function docker_build_with_version {
   local dockerfile="$1"
@@ -107,6 +140,8 @@ function docker_build_with_version {
     fi
   fi
 
+  pull_image "$dockerfile"
+
   # shellcheck disable=SC2016
   parse_output 'docker build '"$BUILD_OPTIONS"' -f "$dockerfile" "${DOCKER_BUILD_CONTEXT}"' \
                "tail -n 1 | awk '/Successfully built|(^--> )?(Using cache )?[a-fA-F0-9]+$/{print \$NF}'" \