grep: add common grep APIs

Signed-off-by: Takahiro Yamashita <[email protected]>

include/fluent-bit/flb_grep.h

@@ -0,0 +1,69 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+
+/*  Fluent Bit
+ *  ==========
+ *  Copyright (C) 2015-2023 The Fluent Bit Authors
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+#ifndef FLB_GREP_H
+#define FLB_GREP_H
+
+#include <fluent-bit/flb_sds.h>
+#include <fluent-bit/flb_regex.h>
+#include <fluent-bit/flb_record_accessor.h>
+
+/* rule types */
+enum flb_grep_rule_type{
+    FLB_GREP_NO_RULE,
+    FLB_GREP_REGEX,
+    FLB_GREP_EXCLUDE
+};
+
+/* actions */
+enum flb_grep_action{
+    FLB_GREP_RET_KEEP,
+    FLB_GREP_RET_EXCLUDE
+};
+
+enum flb_grep_logical_op{
+    FLB_GREP_LOGICAL_OP_LEGACY,
+    FLB_GREP_LOGICAL_OP_OR,
+    FLB_GREP_LOGICAL_OP_AND
+};
+
+struct flb_grep_rule
+{
+    int type;
+    flb_sds_t field;
+    char *regex_pattern;
+    struct flb_regex *regex;
+    struct flb_record_accessor *ra;
+    struct mk_list _head;
+};
+
+
+struct flb_grep {
+    enum flb_grep_rule_type first_rule;
+    enum flb_grep_logical_op op;
+    struct mk_list rules; /* flb_grep_rule list */
+};
+
+
+int flb_grep_filter(msgpack_object map, struct flb_grep *grep_ctx);
+int flb_grep_set_rule_str(struct flb_grep *ctx, enum flb_grep_rule_type type, char *rule_str);
+struct flb_grep *flb_grep_create(enum flb_grep_logical_op op);
+int flb_grep_destroy(struct flb_grep *grep_ctx);
+
+#endif /* FLB_GREP_H */

src/CMakeLists.txt

@@ -77,6 +77,7 @@ set(src
   flb_log_event_encoder_dynamic_field.c
   flb_processor.c
   flb_reload.c
+  flb_grep.c
   )
 
 # Config format

src/flb_grep.c

@@ -0,0 +1,260 @@
+/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+
+/*  Fluent Bit
+ *  ==========
+ *  Copyright (C) 2015-2023 The Fluent Bit Authors
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+#include <fluent-bit/flb_sds.h>
+#include <fluent-bit/flb_str.h>
+#include <fluent-bit/flb_log.h>
+#include <fluent-bit/flb_utils.h>
+#include <fluent-bit/flb_grep.h>
+#include <fluent-bit/flb_mem.h>
+#include <fluent-bit/flb_record_accessor.h>
+
+static int flb_grep_delete_rules(struct mk_list *rules)
+{
+    struct mk_list *tmp;
+    struct mk_list *head;
+    struct flb_grep_rule *rule;
+
+    if (rules == NULL) {
+        return 0;
+    }
+
+    mk_list_foreach_safe(head, tmp, rules) {
+        rule = mk_list_entry(head, struct flb_grep_rule, _head);
+        flb_sds_destroy(rule->field);
+        flb_free(rule->regex_pattern);
+        flb_ra_destroy(rule->ra);
+        flb_regex_destroy(rule->regex);
+        mk_list_del(&rule->_head);
+        flb_free(rule);
+    }
+    return 0;
+}
+
+int flb_grep_destroy(struct flb_grep *grep_ctx)
+{
+    int ret;
+
+    if (grep_ctx == NULL) {
+        return 0;
+    }
+
+    ret = flb_grep_delete_rules(&grep_ctx->rules);
+    flb_free(grep_ctx);
+
+    return ret;
+}
+
+
+static int is_valid_rule_type(struct flb_grep *grep_ctx, enum flb_grep_rule_type type)
+{
+    if (type == FLB_GREP_NO_RULE) {
+        flb_error("%s: invalid type", __FUNCTION__);
+        return -1;
+    }
+
+    if (grep_ctx->op != FLB_GREP_LOGICAL_OP_LEGACY) {
+        /* 'AND'/'OR' case */
+        if (grep_ctx->first_rule != FLB_GREP_NO_RULE /* 2+ rules */ 
+            && grep_ctx->first_rule != type) {
+            flb_error("Both 'regex' and 'exclude' are set.");
+            return FLB_FALSE;
+        }
+    }
+
+    return FLB_TRUE;
+}
+
+/*
+ * rule_str format is "KEY REGEX" .
+ * e.g. hostname *.com
+ */
+int flb_grep_set_rule_str(struct flb_grep *grep_ctx, enum flb_grep_rule_type type, char *rule_str)
+{
+    flb_sds_t tmp;
+    struct mk_list *split;
+    struct flb_split_entry *sentry;
+    struct flb_grep_rule *rule = NULL;
+
+    if (grep_ctx == NULL || rule_str == NULL) {
+        flb_error("%s: input error", __FUNCTION__);
+        return -1;
+    }
+
+    if (is_valid_rule_type(grep_ctx, type) != FLB_TRUE) {
+        return -1;
+    }
+
+    rule = flb_malloc(sizeof(struct flb_grep_rule));
+    if (rule == NULL) {
+        flb_errno();
+        return -1;
+    }
+    rule->type = type;
+    if (grep_ctx->first_rule == FLB_GREP_NO_RULE) {
+        grep_ctx->first_rule = type;
+    }
+
+    /* As a value we expect a pair of field name and a regular expression */
+    split = flb_utils_split(rule_str, ' ', 1);
+    if (mk_list_size(split) != 2) {
+        flb_error("invalid regex, expected field and regular expression");
+        flb_free(rule);
+        flb_utils_split_free(split);
+        return -1;
+    }
+    /* Get first value (field) */
+    sentry = mk_list_entry_first(split, struct flb_split_entry, _head);
+    if (*sentry->value == '$') {
+        rule->field = flb_sds_create_len(sentry->value, sentry->len);
+    }
+    else {
+        rule->field = flb_sds_create_size(sentry->len + 2);
+        tmp = flb_sds_cat(rule->field, "$", 1);
+        rule->field = tmp;
+
+        tmp = flb_sds_cat(rule->field, sentry->value, sentry->len);
+        rule->field = tmp;
+    }
+
+    /* Get remaining content (regular expression) */
+    sentry = mk_list_entry_last(split, struct flb_split_entry, _head);
+    rule->regex_pattern = flb_strndup(sentry->value, sentry->len);
+    if (rule->regex_pattern == NULL) {
+        flb_errno();
+        flb_free(rule);
+        flb_utils_split_free(split);
+        return -1;
+    }
+
+    /* Release split */
+    flb_utils_split_free(split);
+
+    /* Create a record accessor context for this rule */
+    rule->ra = flb_ra_create(rule->field, FLB_FALSE);
+    if (!rule->ra) {
+        flb_error("invalid record accessor? '%s'", rule->field);
+        flb_free(rule);
+        return -1;
+    }
+
+    /* Convert string to regex pattern */
+    rule->regex = flb_regex_create(rule->regex_pattern);
+    if (!rule->regex) {
+        flb_error("could not compile regex pattern '%s'",
+                  rule->regex_pattern);
+        flb_free(rule);
+        return -1;
+    }
+
+    /* Link to parent list */
+    mk_list_add(&rule->_head, &grep_ctx->rules);
+
+    return 0;
+}
+
+struct flb_grep *flb_grep_create(enum flb_grep_logical_op op)
+{
+    struct flb_grep *ctx = NULL;
+
+    ctx = flb_calloc(1, sizeof(struct flb_grep));
+    if (ctx == NULL) {
+        return NULL;
+    }
+
+    ctx->first_rule = FLB_GREP_NO_RULE;
+    ctx->op = op;
+    mk_list_init(&ctx->rules);
+
+    return ctx;
+}
+
+static int flb_grep_filter_legacy(msgpack_object map,
+                                  struct flb_grep *grep_ctx)
+{
+    ssize_t ret;
+    struct mk_list *head;
+    struct flb_grep_rule *rule;
+
+    /* For each rule, validate against map fields */
+    mk_list_foreach(head, &grep_ctx->rules) {
+        rule = mk_list_entry(head, struct flb_grep_rule, _head);
+
+        ret = flb_ra_regex_match(rule->ra, map, rule->regex, NULL);
+        if (ret <= 0) { /* no match */
+            if (rule->type == FLB_GREP_REGEX) {
+                return FLB_GREP_RET_EXCLUDE;
+            }
+        }
+        else {
+            if (rule->type == FLB_GREP_EXCLUDE) {
+                return FLB_GREP_RET_EXCLUDE;
+            }
+            else {
+                return FLB_GREP_RET_KEEP;
+            }
+        }
+    }
+
+    return FLB_GREP_RET_KEEP;
+}
+
+static int flb_grep_filter_data_and_or(msgpack_object map, struct flb_grep *ctx)
+{
+    ssize_t ra_ret;
+    int found = FLB_FALSE;
+    struct mk_list *head;
+    struct flb_grep_rule *rule;
+
+    /* For each rule, validate against map fields */
+    mk_list_foreach(head, &ctx->rules) {
+        found = FLB_FALSE;
+        rule = mk_list_entry(head, struct flb_grep_rule, _head);
+
+        ra_ret = flb_ra_regex_match(rule->ra, map, rule->regex, NULL);
+        if (ra_ret > 0) {
+            found = FLB_TRUE;
+        }
+
+        if (ctx->op == FLB_GREP_LOGICAL_OP_OR && found == FLB_TRUE) {
+            /* OR case: One rule is matched. */
+            goto grep_filter_data_and_or_end;
+        }
+        else if (ctx->op == FLB_GREP_LOGICAL_OP_AND && found == FLB_FALSE) {
+            /* AND case: One rule is not matched */
+            goto grep_filter_data_and_or_end;
+        }
+    }
+
+ grep_filter_data_and_or_end:
+    if (rule->type == FLB_GREP_REGEX) {
+        return found ? FLB_GREP_RET_KEEP : FLB_GREP_RET_EXCLUDE;
+    }
+
+    /* rule is exclude */
+    return found ? FLB_GREP_RET_EXCLUDE : FLB_GREP_RET_KEEP;
+}
+
+int flb_grep_filter(msgpack_object map, struct flb_grep *grep_ctx)
+{
+    if (grep_ctx->op == FLB_GREP_LOGICAL_OP_LEGACY) {
+        return flb_grep_filter_legacy(map, grep_ctx);
+    }
+    return flb_grep_filter_data_and_or(map, grep_ctx);
+}

tests/internal/CMakeLists.txt

@@ -39,6 +39,7 @@ set(UNIT_TESTS_FILES
   env.c
   log.c
   processor.c
+  grep.c
   )
 
 # Config format