Handle SSL proxying and other fixes

Enable mod_ssl and enable proxying to ssl-terminated endpoints.

In the case where the artifact is not found, return NULL instead
of the bogus "Artifact_not_found" url, otherwise we can end up in
a loop where we continuously append that to the url.

Strip trailing slashes from the returned proxy target.  We can't
guarantee that folks won't have a '/' at the end of the artifact
url they return to Zuul (and in fact, it's probably more correct
that they do).  But our regex in mod_rewrite guarantees that we
will add a slash to it.  One sure way to handle this is just to
strip it from the data returned from Zuul if present.

Add a .dockerignore file with both itself and the Dockerfile
added, so that docker won't rebuild extra layers (like the C++
compile layer) if we just change the Dockerfile.

Change-Id: I00dfd0b6842abedf938702a816698d1c6526974d

.dockerignore

@@ -0,0 +1,2 @@
+.dockerignore
+Dockerfile

Dockerfile

@@ -34,7 +34,7 @@ RUN apt-get update \
   && apt-get install -y dumb-init apache2 $(cat /run.txt) \
   && apt-get clean \
   && rm -rf /var/lib/apt/lists/* /run.txt \
-  && a2enmod rewrite proxy proxy_http
+  && a2enmod rewrite proxy proxy_http ssl
 COPY ./vhost.conf /etc/apache2/sites-available/000-default.conf
 COPY --from=builder /usr/local /usr/local
 

vhost.conf

@@ -9,4 +9,5 @@
         RewriteMap preview "prg://usr/local/bin/zuul-preview"
         RewriteRule "^/notfound" "-" [F]
         RewriteRule "^/?(.*)$" "${preview:%{ENV:ZUUL_API_URL} %{HTTP_HOST}|http://localhost/notfound}/$1" [P]
+        SSLProxyEngine on
 </VirtualHost>

zuul-preview/main.cc

@@ -165,7 +165,7 @@ int main(int, char**)
       auto body = response.extract_json().get();
       auto artifacts = body["artifacts"].as_array();
 
-      string artifact_url = "Artifact_not_found";
+      string artifact_url = "NULL";
       for (uint i = 0; i < artifacts.size(); i++) {
         if (artifacts[i].has_field("metadata") &&
             artifacts[i]["metadata"].has_field("type") &&
@@ -174,6 +174,11 @@ int main(int, char**)
         }
       }
 
+      // The apache config is guaranteed to add a / to this, so avoid
+      // double slashes on the end.
+      if (artifact_url.back() == '/') {
+        artifact_url.pop_back();
+      }
       cout << artifact_url << endl;
 
       cache.put(hostname, artifact_url);