feat: Add get_proxy_host_logs tool for reading nginx proxy host logs

Reads nginx access/error logs directly from a mounted NPM log directory,
enabling agents to debug proxy issues without SSH access. Requires mounting
NPM's /data/logs volume and setting NPM_LOG_DIR.

Also includes a feature request PRD for proposing a native log API upstream.

tests/test_logs.py

@@ -0,0 +1,146 @@
+"""Tests for the log reader module."""
+
+import pytest
+
+from npm_mcp.exceptions import NpmLogError
+from npm_mcp.logs import (
+    is_log_dir_configured,
+    list_available_logs,
+    read_log_lines,
+)
+
+SAMPLE_ACCESS_LOG = (
+    '[22/May/2025:10:00:01 +0000] - 200 200 - GET https app.example.com'
+    ' "/" [Client 10.0.0.1] [Length 1542] "Mozilla/5.0" "-"\n'
+    '[22/May/2025:10:00:02 +0000] - 301 301 - GET http app.example.com'
+    ' "/old-path" [Client 10.0.0.2] [Length 0] "curl/7.88" "-"\n'
+    '[22/May/2025:10:00:03 +0000] - 404 404 - GET https app.example.com'
+    ' "/missing" [Client 10.0.0.1] [Length 548] "Mozilla/5.0" "-"\n'
+    '[22/May/2025:10:00:04 +0000] - 200 200 - POST https app.example.com'
+    ' "/api/data" [Client 10.0.0.3] [Length 256] "python-requests/2.31" "-"\n'
+    '[22/May/2025:10:00:05 +0000] - 502 502 - GET https app.example.com'
+    ' "/health" [Client 10.0.0.1] [Length 166] "kube-probe/1.28" "-"\n'
+)
+
+SAMPLE_ERROR_LOG = (
+    "2025/05/22 10:00:05 [error] 42#42: *123 connect() failed"
+    " (111: Connection refused) while connecting to upstream,"
+    " client: 10.0.0.1, server: app.example.com\n"
+)
+
+
+@pytest.fixture
+def log_dir(tmp_path, monkeypatch):
+    """Create a temp log directory with sample log files."""
+    logs = tmp_path / "logs"
+    logs.mkdir()
+
+    (logs / "proxy-host-5_access.log").write_text(SAMPLE_ACCESS_LOG)
+    (logs / "proxy-host-5_error.log").write_text(SAMPLE_ERROR_LOG)
+    (logs / "proxy-host-12_access.log").write_text("")
+    (logs / "fallback_error.log").write_text("global error\n")
+
+    monkeypatch.setattr("npm_mcp.logs.settings.log_dir", str(logs))
+    return logs
+
+
+@pytest.fixture
+def no_log_dir(monkeypatch):
+    """Ensure log_dir is unconfigured."""
+    monkeypatch.setattr("npm_mcp.logs.settings.log_dir", "")
+
+
+class TestReadLogLines:
+    def test_read_access_log(self, log_dir):
+        result = read_log_lines(host_id=5, log_type="access")
+        assert result["host_id"] == 5
+        assert result["log_type"] == "access"
+        assert result["file"] == "proxy-host-5_access.log"
+        assert result["returned_lines"] == 5
+        assert result["total_lines_in_file"] == 5
+        assert "app.example.com" in result["lines"][0]
+
+    def test_read_error_log(self, log_dir):
+        result = read_log_lines(host_id=5, log_type="error")
+        assert result["log_type"] == "error"
+        assert result["returned_lines"] == 1
+        assert "Connection refused" in result["lines"][0]
+
+    def test_lines_limit(self, log_dir):
+        result = read_log_lines(host_id=5, log_type="access", lines=2)
+        assert result["returned_lines"] == 2
+        assert "10:00:04" in result["lines"][0]
+        assert "10:00:05" in result["lines"][1]
+
+    def test_lines_capped_at_max(self, log_dir):
+        result = read_log_lines(host_id=5, log_type="access", lines=9999)
+        assert result["returned_lines"] == 5
+
+    def test_search_filter(self, log_dir):
+        result = read_log_lines(host_id=5, log_type="access", search="404")
+        assert result["returned_lines"] == 1
+        assert result["matched_lines"] == 1
+        assert result["total_lines_in_file"] is None
+        assert "/missing" in result["lines"][0]
+
+    def test_search_case_insensitive(self, log_dir):
+        result = read_log_lines(host_id=5, log_type="access", search="MOZILLA")
+        assert result["returned_lines"] == 2
+
+    def test_search_by_ip(self, log_dir):
+        result = read_log_lines(host_id=5, log_type="access", search="10.0.0.1")
+        assert result["returned_lines"] == 3
+
+    def test_nonexistent_host(self, log_dir):
+        with pytest.raises(NpmLogError, match="Log file not found"):
+            read_log_lines(host_id=999, log_type="access")
+
+    def test_empty_log_file(self, log_dir):
+        with pytest.raises(NpmLogError, match="Log file not found"):
+            read_log_lines(host_id=12, log_type="error")
+
+    def test_invalid_log_type(self, log_dir):
+        with pytest.raises(NpmLogError, match="Invalid log type"):
+            read_log_lines(host_id=5, log_type="combined")
+
+    def test_no_log_dir_configured(self, no_log_dir):
+        with pytest.raises(NpmLogError, match="NPM_LOG_DIR is not configured"):
+            read_log_lines(host_id=5, log_type="access")
+
+    def test_nonexistent_log_dir(self, monkeypatch):
+        monkeypatch.setattr("npm_mcp.logs.settings.log_dir", "/nonexistent/path")
+        with pytest.raises(NpmLogError, match="does not exist"):
+            read_log_lines(host_id=5, log_type="access")
+
+
+class TestIsLogDirConfigured:
+    def test_configured(self, log_dir):
+        assert is_log_dir_configured() is True
+
+    def test_not_configured(self, no_log_dir):
+        assert is_log_dir_configured() is False
+
+    def test_configured_but_missing(self, monkeypatch):
+        monkeypatch.setattr("npm_mcp.logs.settings.log_dir", "/nonexistent")
+        assert is_log_dir_configured() is False
+
+
+class TestListAvailableLogs:
+    def test_lists_proxy_host_logs_only(self, log_dir):
+        results = list_available_logs()
+        files = {r["file"] for r in results}
+        assert "proxy-host-5_access.log" in files
+        assert "proxy-host-5_error.log" in files
+        assert "proxy-host-12_access.log" in files
+        assert "fallback_error.log" not in files
+
+    def test_correct_metadata(self, log_dir):
+        results = list_available_logs()
+        access_5 = next(r for r in results if r["file"] == "proxy-host-5_access.log")
+        assert access_5["host_id"] == 5
+        assert access_5["log_type"] == "access"
+        assert access_5["size_bytes"] > 0
+
+    def test_not_configured(self, no_log_dir):
+        with pytest.raises(NpmLogError, match="NPM_LOG_DIR is not configured"):
+            list_available_logs()