nix(loadtest): group results by status, method and URL

Different requests hit different code paths and perform very
differently. By looking at each request type separately, we should be
able to get a much better idea of what kind of change in performance
we're looking at and where the root cause might be.

It will hopefully also allow us to migrate some of the other test-cases
into the main loadtest.

nix/tools/loadtest.nix

@@ -267,7 +267,8 @@ let
         workingDir = "/";
       }
       ''
-        ${vegeta}/bin/vegeta report -type=json "$_arg_file" \
+        ${vegeta}/bin/vegeta encode "$_arg_file" \
+          | ${jq}/bin/jq --slurp 'map(select(.url != "")) | group_by("\(.code) \(.method) \(.url)") | map({("\(.[0].code) \(.[0].method) \(.[0].url)" | sub("http://postgrest";"")): add | .latency / length | 10e6 / . }) | .[]' \
           | ${jq}/bin/jq --arg branch "$(basename "$_arg_file" .bin)" '. + {branch: $branch}'
       '';
 
@@ -281,10 +282,10 @@ let
         import pandas as pd
 
         pd.read_json(sys.stdin) \
-          .set_index('param') \
+          .set_index('rate') \
-          .loc['rate'] \
+          .drop(['branch']) \
           .convert_dtypes() \
-          .to_markdown(sys.stdout, floatfmt='.0f')
+          .to_markdown(sys.stdout, floatfmt='.1f')
       '';
 
 
@@ -304,8 +305,8 @@ let
         echo -e "## Loadtest results $marker\n"
 
         find loadtest -type f -iname '*.bin' -exec ${reporter} {} \; \
-          | ${jq}/bin/jq '[paths(scalars) as $path | {param: $path | join("."), (.branch): getpath($path)}]' \
+          | ${jq}/bin/jq '[paths(scalars) as $path | {rate: $path | join("."), (.branch): getpath($path)}]' \
-          | ${jq}/bin/jq --slurp 'flatten | group_by(.param) | map(add)' \
+          | ${jq}/bin/jq --slurp 'flatten | group_by(.rate) | map(add)' \
           | ${toMarkdown}
 
         echo -e "\n\n## Loadtest elapsed seconds vs CPU/MEM usage $marker\n"