test(observability-proxy): preserve JSON seed request bodies

Send JSON seeds with their content type so VictoriaLogs does not consume
log records while parsing form parameters before ingestion.

Fixes: ebb5a9cec4 ("test(observability-proxy): cover the namespace logs scope end to end")
Assisted-by: LLM
Signed-off-by: Aleksei Sviridkin <f@lex.la>

hack/e2e-chainsaw/observability-proxy/lib.sh

@@ -25,7 +25,7 @@ forward() {
 ingest() {
   printf '{"kubernetes_namespace_name":"%s","log":"%s"}\n' "$1" "$2" |
     timeout 15 curl --silent --show-error --fail --data-binary @- \
-      --header "AccountID: ${3:-0}" --header "ProjectID: 0" \
+      --header 'Content-Type: application/json' --header "AccountID: ${3:-0}" --header "ProjectID: 0" \
       "$STORE/insert/jsonline?_stream_fields=kubernetes_namespace_name&_msg_field=log"
 }
 

hack/observability-proxy-seed.bats

@@ -0,0 +1,51 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+REPO_ROOT="$(cd "$(dirname "${BATS_TEST_FILENAME:-$0}")/.." && pwd)"
+
+setup() {
+    strict_setup
+    mkdir -p "$BATS_TEST_TMPDIR/bin"
+    export SEED_CAPTURE="$BATS_TEST_TMPDIR/seed"
+    export TMPDIR="$BATS_TEST_TMPDIR"
+    export PATH="$BATS_TEST_TMPDIR/bin:$PATH"
+    cat > "$BATS_TEST_TMPDIR/bin/curl" <<'EOF'
+#!/usr/bin/env bash
+set -eu
+printf '%s\n' "$@" > "$SEED_CAPTURE.args"
+cat > "$SEED_CAPTURE.body"
+if ! grep --fixed-strings --line-regexp --quiet 'Content-Type: application/json' "$SEED_CAPTURE.args"; then
+    echo 'seed request is missing its JSON content type' >&2
+    exit 22
+fi
+EOF
+    chmod +x "$BATS_TEST_TMPDIR/bin/curl"
+}
+
+assert_seed_request() {
+    local account=$1
+    # shellcheck source=e2e-chainsaw/observability-proxy/lib.sh
+    . "$REPO_ROOT/hack/e2e-chainsaw/observability-proxy/lib.sh"
+    if [ "$account" = 0 ]; then
+        ingest tenant-test-logsa e2e-marker-a
+    else
+        ingest tenant-test-logsa e2e-marker-a "$account"
+    fi
+    grep --fixed-strings --line-regexp --quiet "AccountID: $account" "$SEED_CAPTURE.args"
+    grep --fixed-strings --line-regexp --quiet 'ProjectID: 0' "$SEED_CAPTURE.args"
+    grep --fixed-strings --line-regexp --quiet 'http://localhost:19471/insert/jsonline?_stream_fields=kubernetes_namespace_name&_msg_field=log' "$SEED_CAPTURE.args"
+    grep --fixed-strings --line-regexp --quiet -- '--data-binary' "$SEED_CAPTURE.args"
+    grep --fixed-strings --line-regexp --quiet '@-' "$SEED_CAPTURE.args"
+    printf '%s\n' '{"kubernetes_namespace_name":"tenant-test-logsa","log":"e2e-marker-a"}' > "$SEED_CAPTURE.expected"
+    cmp "$SEED_CAPTURE.expected" "$SEED_CAPTURE.body"
+    rm "$body"
+}
+
+@test "observability seeds send JSON without consuming the body as form data" {
+    assert_seed_request 0
+}
+
+@test "observability seeds preserve an explicit VictoriaLogs account" {
+    assert_seed_request 7
+}