MEDIUM: stats: Add JSON output option to show (info|stat)
Add a json parameter to show (info|stat) which will output information
in JSON format. A follow-up patch will add a JSON schema which describes
the format of the JSON output of these commands.
The JSON output is without any extra whitespace in order to reduce the
volume of output. For human consumption passing the output through a
pretty printer may be helpful.
e.g.:
$ echo "show info json" | socat /var/run/haproxy.stat stdio | \
python -m json.tool
STAT_STARTED has bee added in order to track if show output has begun or
not. This is used in order to allow the JSON output routines to only insert
a "," between elements when needed. I would value any feedback on how this
might be done better.
Signed-off-by: Simon Horman <horms@verge.net.au>
diff --git a/src/stats.c b/src/stats.c
index 6bb33e8..66ab8d8 100644
--- a/src/stats.c
+++ b/src/stats.c
@@ -229,6 +229,7 @@
* http_stats_io_handler()
* -> stats_dump_stat_to_buffer() // same as above, but used for CSV or HTML
* -> stats_dump_csv_header() // emits the CSV headers (same as above)
+ * -> stats_dump_json_header() // emits the JSON headers (same as above)
* -> stats_dump_html_head() // emits the HTML headers
* -> stats_dump_html_info() // emits the equivalent of "show info" at the top
* -> stats_dump_proxy_to_buffer() // same as above, valid for CSV and HTML
@@ -239,6 +240,7 @@
* -> stats_dump_be_stats()
* -> stats_dump_html_px_end()
* -> stats_dump_html_end() // emits HTML trailer
+ * -> stats_dump_json_end() // emits JSON trailer
*/
@@ -294,6 +296,58 @@
}
}
+/* Limit JSON integer values to the range [-(2**53)+1, (2**53)-1] as per
+ * the recommendation for interoperable integers in section 6 of RFC 7159.
+ */
+#define JSON_INT_MAX ((1ULL << 53) - 1)
+#define JSON_INT_MIN (0 - JSON_INT_MAX)
+
+/* Emits a stats field value and its type in JSON.
+ * Returns non-zero on success, 0 on error.
+ */
+int stats_emit_json_data_field(struct chunk *out, const struct field *f)
+{
+ int old_len;
+ char buf[20];
+ const char *type, *value = buf, *quote = "";
+
+ switch (field_format(f, 0)) {
+ case FF_EMPTY: return 1;
+ case FF_S32: type = "\"s32\"";
+ snprintf(buf, sizeof(buf), "%d", f->u.s32);
+ break;
+ case FF_U32: type = "\"u32\"";
+ snprintf(buf, sizeof(buf), "%u", f->u.u32);
+ break;
+ case FF_S64: type = "\"s64\"";
+ if (f->u.s64 < JSON_INT_MIN || f->u.s64 > JSON_INT_MAX)
+ return 0;
+ type = "\"s64\"";
+ snprintf(buf, sizeof(buf), "%lld", (long long)f->u.s64);
+ break;
+ case FF_U64: if (f->u.u64 > JSON_INT_MAX)
+ return 0;
+ type = "\"u64\"";
+ snprintf(buf, sizeof(buf), "%llu",
+ (unsigned long long) f->u.u64);
+ break;
+ case FF_STR: type = "\"str\"";
+ value = field_str(f, 0);
+ quote = "\"";
+ break;
+ default: snprintf(buf, sizeof(buf), "%u", f->type);
+ type = buf;
+ value = "unknown";
+ quote = "\"";
+ break;
+ }
+
+ old_len = out->len;
+ chunk_appendf(out, ",\"value\":{\"type\":%s,\"value\":%s%s%s}",
+ type, quote, value, quote);
+ return !(old_len == out->len);
+}
+
/* Emits an encoding of the field type on 3 characters followed by a delimiter.
* Returns non-zero on success, 0 if the buffer is full.
*/
@@ -337,6 +391,55 @@
return chunk_appendf(out, "%c%c%c%c", origin, nature, scope, delim);
}
+/* Emits an encoding of the field type as JSON.
+ * Returns non-zero on success, 0 if the buffer is full.
+ */
+int stats_emit_json_field_tags(struct chunk *out, const struct field *f)
+{
+ const char *origin, *nature, *scope;
+ int old_len;
+
+ switch (field_origin(f, 0)) {
+ case FO_METRIC: origin = "Metric"; break;
+ case FO_STATUS: origin = "Status"; break;
+ case FO_KEY: origin = "Key"; break;
+ case FO_CONFIG: origin = "Config"; break;
+ case FO_PRODUCT: origin = "Product"; break;
+ default: origin = "Unknown"; break;
+ }
+
+ switch (field_nature(f, 0)) {
+ case FN_GAUGE: nature = "Gauge"; break;
+ case FN_LIMIT: nature = "Limit"; break;
+ case FN_MIN: nature = "Min"; break;
+ case FN_MAX: nature = "Max"; break;
+ case FN_RATE: nature = "Rate"; break;
+ case FN_COUNTER: nature = "Counter"; break;
+ case FN_DURATION: nature = "Duration"; break;
+ case FN_AGE: nature = "Age"; break;
+ case FN_TIME: nature = "Time"; break;
+ case FN_NAME: nature = "Name"; break;
+ case FN_OUTPUT: nature = "Output"; break;
+ case FN_AVG: nature = "Avg"; break;
+ default: nature = "Unknown"; break;
+ }
+
+ switch (field_scope(f, 0)) {
+ case FS_PROCESS: scope = "Process"; break;
+ case FS_SERVICE: scope = "Service"; break;
+ case FS_SYSTEM: scope = "System"; break;
+ case FS_CLUSTER: scope = "Cluster"; break;
+ default: scope = "Unknown"; break;
+ }
+
+ old_len = out->len;
+ chunk_appendf(out, "\"tags\":{"
+ "\"origin\":\"%s\","
+ "\"nature\":\"%s\","
+ "\"scope\":\"%s\""
+ "}", origin, nature, scope);
+ return !(old_len == out->len);
+}
/* Dump all fields from <stats> into <out> using CSV format */
static int stats_dump_fields_csv(struct chunk *out, const struct field *stats)
@@ -381,6 +484,123 @@
return 1;
}
+/* Dump all fields from <stats> into <out> using the "show info json" format */
+static int stats_dump_json_info_fields(struct chunk *out,
+ const struct field *info)
+{
+ int field;
+ int started = 0;
+
+ if (!chunk_strcat(out, "["))
+ return 0;
+
+ for (field = 0; field < INF_TOTAL_FIELDS; field++) {
+ int old_len;
+
+ if (!field_format(info, field))
+ continue;
+
+ if (started && !chunk_strcat(out, ","))
+ goto err;
+ started = 1;
+
+ old_len = out->len;
+ chunk_appendf(out,
+ "{\"field\":{\"pos\":%d,\"name\":\"%s\"},"
+ "\"processNum\":%u,",
+ field, info_field_names[field],
+ info[INF_PROCESS_NUM].u.u32);
+ if (old_len == out->len)
+ goto err;
+
+ if (!stats_emit_json_field_tags(out, &info[field]))
+ goto err;
+
+ if (!stats_emit_json_data_field(out, &info[field]))
+ goto err;
+
+ if (!chunk_strcat(out, "}"))
+ goto err;
+ }
+
+ if (!chunk_strcat(out, "]"))
+ goto err;
+ return 1;
+
+err:
+ chunk_reset(out);
+ chunk_appendf(out, "{\"errorStr\":\"output buffer too short\"}");
+ return 0;
+}
+
+/* Dump all fields from <stats> into <out> using a typed "field:desc:type:value" format */
+static int stats_dump_fields_json(struct chunk *out, const struct field *stats,
+ int first_stat)
+{
+ int field;
+ int started = 0;
+
+ if (!first_stat && !chunk_strcat(out, ","))
+ return 0;
+ if (!chunk_strcat(out, "["))
+ return 0;
+
+ for (field = 0; field < ST_F_TOTAL_FIELDS; field++) {
+ const char *obj_type;
+ int old_len;
+
+ if (!stats[field].type)
+ continue;
+
+ if (started && !chunk_strcat(out, ","))
+ goto err;
+ started = 1;
+
+ switch (stats[ST_F_TYPE].u.u32) {
+ case STATS_TYPE_FE: obj_type = "Frontend"; break;
+ case STATS_TYPE_BE: obj_type = "Backend"; break;
+ case STATS_TYPE_SO: obj_type = "Listener"; break;
+ case STATS_TYPE_SV: obj_type = "Server"; break;
+ default: obj_type = "Unknown"; break;
+ }
+
+ old_len = out->len;
+ chunk_appendf(out,
+ "{"
+ "\"objType\":\"%s\","
+ "\"proxyId\":%d,"
+ "\"id\":%d,"
+ "\"field\":{\"pos\":%d,\"name\":\"%s\"},"
+ "\"processNum\":%u,",
+ obj_type, stats[ST_F_IID].u.u32,
+ stats[ST_F_SID].u.u32, field,
+ stat_field_names[field], stats[ST_F_PID].u.u32);
+ if (old_len == out->len)
+ goto err;
+
+ if (!stats_emit_json_field_tags(out, &stats[field]))
+ goto err;
+
+ if (!stats_emit_json_data_field(out, &stats[field]))
+ goto err;
+
+ if (!chunk_strcat(out, "}"))
+ goto err;
+ }
+
+ if (!chunk_strcat(out, "]"))
+ goto err;
+
+ return 1;
+
+err:
+ chunk_reset(out);
+ if (!first_stat)
+ chunk_strcat(out, ",");
+ chunk_appendf(out, "{\"errorStr\":\"output buffer too short\"}");
+ return 0;
+}
+
/* Dump all fields from <stats> into <out> using the HTML format. A column is
* reserved for the checkbox is ST_SHOWADMIN is set in <flags>. Some extra info
* are provided if ST_SHLGNDS is present in <flags>.
@@ -1022,15 +1242,26 @@
int stats_dump_one_line(const struct field *stats, unsigned int flags, struct proxy *px, struct appctx *appctx)
{
+ int ret;
+
if ((px->cap & PR_CAP_BE) && px->srv && (appctx->ctx.stats.flags & STAT_ADMIN))
flags |= ST_SHOWADMIN;
if (appctx->ctx.stats.flags & STAT_FMT_HTML)
- return stats_dump_fields_html(&trash, stats, flags);
+ ret = stats_dump_fields_html(&trash, stats, flags);
else if (appctx->ctx.stats.flags & STAT_FMT_TYPED)
- return stats_dump_fields_typed(&trash, stats);
+ ret = stats_dump_fields_typed(&trash, stats);
+ else if (appctx->ctx.stats.flags & STAT_FMT_JSON)
+ ret = stats_dump_fields_json(&trash, stats,
+ !(appctx->ctx.stats.flags &
+ STAT_STARTED));
else
- return stats_dump_fields_csv(&trash, stats);
+ ret = stats_dump_fields_csv(&trash, stats);
+
+ if (ret)
+ appctx->ctx.stats.flags |= STAT_STARTED;
+
+ return ret;
}
/* Fill <stats> with the frontend statistics. <stats> is
@@ -2258,6 +2489,23 @@
chunk_appendf(&trash, "</body></html>\n");
}
+/* Dumps the stats JSON header to the trash buffer which. The caller is responsible
+ * for clearing it if needed.
+ */
+static void stats_dump_json_header()
+{
+ chunk_strcat(&trash, "[");
+}
+
+
+/* Dumps the JSON stats trailer block to the trash. The caller is responsible
+ * for clearing the trash if needed.
+ */
+static void stats_dump_json_end()
+{
+ chunk_strcat(&trash, "]");
+}
+
/* This function dumps statistics onto the stream interface's read buffer in
* either CSV or HTML format. <uri> contains some HTML-specific parameters that
* are ignored for CSV format (hence <uri> may be NULL there). It returns 0 if
@@ -2281,6 +2529,8 @@
case STAT_ST_HEAD:
if (appctx->ctx.stats.flags & STAT_FMT_HTML)
stats_dump_html_head(uri);
+ else if (appctx->ctx.stats.flags & STAT_FMT_JSON)
+ stats_dump_json_header(uri);
else if (!(appctx->ctx.stats.flags & STAT_FMT_TYPED))
stats_dump_csv_header();
@@ -2329,8 +2579,11 @@
/* fall through */
case STAT_ST_END:
- if (appctx->ctx.stats.flags & STAT_FMT_HTML) {
- stats_dump_html_end();
+ if (appctx->ctx.stats.flags & (STAT_FMT_HTML|STAT_FMT_JSON)) {
+ if (appctx->ctx.stats.flags & STAT_FMT_HTML)
+ stats_dump_html_end();
+ else
+ stats_dump_json_end();
if (bi_putchk(rep, &trash) == -1) {
si_applet_cant_put(si);
return 0;
@@ -2757,6 +3010,7 @@
return 1;
}
+
/* This I/O handler runs as an applet embedded in a stream interface. It is
* used to send HTTP stats over a TCP socket. The mechanism is very simple.
* appctx->st0 contains the operation in progress (dump, done). The handler
@@ -3032,6 +3286,8 @@
if (appctx->ctx.stats.flags & STAT_FMT_TYPED)
stats_dump_typed_info_fields(&trash, info);
+ else if (appctx->ctx.stats.flags & STAT_FMT_JSON)
+ stats_dump_json_info_fields(&trash, info);
else
stats_dump_info_fields(&trash, info);
@@ -3108,6 +3364,8 @@
if (strcmp(args[2], "typed") == 0)
appctx->ctx.stats.flags |= STAT_FMT_TYPED;
+ else if (strcmp(args[2], "json") == 0)
+ appctx->ctx.stats.flags |= STAT_FMT_JSON;
return 0;
}
@@ -3138,9 +3396,13 @@
appctx->ctx.stats.sid = atoi(args[4]);
if (strcmp(args[5], "typed") == 0)
appctx->ctx.stats.flags |= STAT_FMT_TYPED;
+ else if (strcmp(args[5], "json") == 0)
+ appctx->ctx.stats.flags |= STAT_FMT_JSON;
}
else if (strcmp(args[2], "typed") == 0)
appctx->ctx.stats.flags |= STAT_FMT_TYPED;
+ else if (strcmp(args[2], "json") == 0)
+ appctx->ctx.stats.flags |= STAT_FMT_JSON;
return 0;
}