Crontab

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mongoose-os-libs/crontab mgos_crontab.h    

Crontab wraps cron core and maintains a persisted set of cron jobs. Crontab file is simply a JSON file (actually managed by jstore) which looks like this:

{"items":[
  ["1", {
    "at": "0 0 7 * * MON-FRI",
    "enable": true,
    "action": "foo",
    "payload": {"a": 1, "b": 2}
  }],
  ["2", {
    "at": "0 */2 1-4 * * *",
    "enable": true,
    "action": "bar"
  }]
]}

For the cron expression syntax, see cron core docs.


Crontab wraps cron core and maintains a persisted set of cron jobs. Crontab file is simply a JSON file (actually managed by jstore) which looks like this:

{"items":[
  ["1", {
    "at": "0 0 7 * * MON-FRI",
    "enable": true,
    "action": "foo",
    "payload": {"a": 1, "b": 2}
  }],
  ["2", {
    "at": "0 30 23 30 * *",
    "enable": true,
    "action": "bar"
  }]
]}

This file is maintained by a set of API functions (see below).

Obviously, crontab file contains a set of cron jobs, each of which consists, at least, of the cron expression like 0 0 7 * * MON-FRI (refer to the cron core for the expression syntax docs) and an action to be taken. Action is just a string, in the example above there are two actions: foo and bar. Additionally, there can be a payload, which is an arbitrary JSON. Payload is just a set of parameters for the action.

Obviously, there should be a mapping between those string actions and the corresponding functions to be called; this is what mgos_crontab_register_handler() is for.

Example:

static void my_foo_cb(struct mg_str action,
                      struct mg_str payload, void *userdata) {
  LOG(LL_INFO, ("Crontab foo job fired! Payload: %.*s", payload.len,
payload.p));
  (void) action;
  (void) userdata;
}

// Somewhere else:
mgos_crontab_register_handler("foo", my_foo_cb, NULL);

The code above maps action foo in the JSON to the callback my_foo_cb.


(

#define MGOS_CRONTAB_INVALID_JOB_ID ((mgos_crontab_job_id_t) 0)

Invalid value for the crontab job id.

(*mgos_crontab_iterate_cb)

typedef void (*mgos_crontab_iterate_cb)(mgos_crontab_job_id_t id,
                                        struct mg_str at, bool enable,
                                        struct mg_str action,
                                        struct mg_str payload, void *userdata);

Callback for mgos_crontab_iterate(); all string data is invalidated when the callback returns.

(*mgos_crontab_cb)

typedef void (*mgos_crontab_cb)(struct mg_str action, struct mg_str payload,
                                void *userdata);

Prototype for a job handler to be registered with mgos_crontab_register_handler().

mgos_crontab_job_add

bool mgos_crontab_job_add(struct mg_str at, bool enable, struct mg_str action,
                          struct mg_str payload, mgos_crontab_job_id_t *pid,
                          char **perr);

Add a new job. Passed string data is not retained. If pid is not NULL, resulting job id is written there.

Returns true in case of success, false otherwise.

If perr is not NULL, the error message will be written there (or NULL in case of success). The caller should free the error message.

mgos_crontab_job_edit

bool mgos_crontab_job_edit(mgos_crontab_job_id_t id, struct mg_str at,
                           bool enable, struct mg_str action,
                           struct mg_str payload, char **perr);

Edit a job by its id. Passed string data is not retained.

Returns true in case of success, false otherwise.

If perr is not NULL, the error message will be written there (or NULL in case of success). The caller should free the error message.

mgos_crontab_job_remove

bool mgos_crontab_job_remove(mgos_crontab_job_id_t id, char **perr);

Remove a job by its id.

Returns true in case of success, false otherwise.

If perr is not NULL, the error message will be written there (or NULL in case of success). The caller should free the error message.

mgos_crontab_job_get

bool mgos_crontab_job_get(mgos_crontab_job_id_t id, struct mg_str *at,
                          bool *enable, struct mg_str *action,
                          struct mg_str *payload, char **perr);

Get job details by the job id. All output pointers (at, enable, action, payload) are optional (allowed to be NULL). For non-NULL string outputs (at, action and payload), the memory is allocated separately and the caller should free it.

Returns true in case of success, false otherwise.

If perr is not NULL, the error message will be written there (or NULL in case of success). The caller should free the error message.

mgos_crontab_iterate

bool mgos_crontab_iterate(mgos_crontab_iterate_cb cb, void *userdata,
                          char **perr);

Iterate over all jobs in crontab, see mgos_crontab_iterate_cb for details.

Returns true in case of success, false otherwise.

If perr is not NULL, the error message will be written there (or NULL in case of success). The caller should free the error message.

mgos_crontab_register_handler

void mgos_crontab_register_handler(struct mg_str action, mgos_crontab_cb cb,
                                   void *userdata);

Add a handler for the given string action

Example:

static void my_foo_cb(struct mg_str action,
                      struct mg_str payload, void *userdata) {
  LOG(LL_INFO, ("Crontab foo job fired! Payload: %.*s", payload.len,
payload.p));
  (void) action;
  (void) userdata;
}

// Somewhere else:
mgos_crontab_register_handler("foo", my_foo_cb, NULL);

The code above maps action foo in the JSON to the callback my_foo_cb.

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