[PATCH] pseudo_db: Flush DB if there is a shutdown request

[PATCH] pseudo_db: Flush DB if there is a shutdown request

[Richard Purdie]

We have some challenges in ensuring the pseudo database is flushed to disk
in things like docker containers since the processes can be killed with no
warning at container termination. Rightly or wrongly, we need to handle this
better.

There is no current way to flush the DB but there is a shutdoen request
mechanism. Whilst we can't force a shutdown from bitbake due to the multiple
connected clients and the existing 3s shutdown isn't enough, we can take the
hint to flush the DB at this time. Further writes are unlikely.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
---
 pseudo_db.c     | 2 +-
 pseudo_db.h     | 1 +
 pseudo_server.c | 1 +
 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/pseudo_db.c b/pseudo_db.c
index 6c48cc8..14bafcb 100644
--- a/pseudo_db.c
+++ b/pseudo_db.c
@@ -399,7 +399,7 @@ signed_ino(ino_t ino) {
 
 #ifdef USE_MEMORY_DB
 
-static void
+void
 pdb_backup() {
         sqlite3_backup *pBackup;
         /* no point in doing this if we don't have a database to back up,
diff --git a/pseudo_db.h b/pseudo_db.h
index 5a4aa59..9d01232 100644
--- a/pseudo_db.h
+++ b/pseudo_db.h
@@ -26,6 +26,7 @@ typedef struct {
 	char *program;
 } log_entry;
 
+extern void pdb_backup(void);
 extern int pdb_maybe_backup(void);
 extern int pdb_cancel_unlink_file(pseudo_msg_t *msg);
 extern int pdb_did_unlink_file(char *path, pseudo_msg_t *msg, int deleting);
diff --git a/pseudo_server.c b/pseudo_server.c
index 84cef05..815c76b 100644
--- a/pseudo_server.c
+++ b/pseudo_server.c
@@ -568,6 +568,7 @@ serve_client(int i) {
 				}
 				in->pathlen = (s - response_path) + 1;
 				/* exit quickly once clients go away, though */
+                               pdb_backup();
 				pseudo_server_timeout = 3;
 			} else {
 				in->type = PSEUDO_MSG_ACK;
-- 
2.32.0

Re: [OE-core] [PATCH] pseudo_db: Flush DB if there is a shutdown request

[Khem Raj]

On 9/25/21 2:35 AM, Richard Purdie wrote:
> We have some challenges in ensuring the pseudo database is flushed to disk
> in things like docker containers since the processes can be killed with no
> warning at container termination. Rightly or wrongly, we need to handle this
> better.
> 
> There is no current way to flush the DB but there is a shutdoen request

typo shutdoen/shutdown

> mechanism. Whilst we can't force a shutdown from bitbake due to the multiple
> connected clients and the existing 3s shutdown isn't enough, we can take the
> hint to flush the DB at this time. Further writes are unlikely.
> 
> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
> ---
>   pseudo_db.c     | 2 +-
>   pseudo_db.h     | 1 +
>   pseudo_server.c | 1 +
>   3 files changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/pseudo_db.c b/pseudo_db.c
> index 6c48cc8..14bafcb 100644
> --- a/pseudo_db.c
> +++ b/pseudo_db.c
> @@ -399,7 +399,7 @@ signed_ino(ino_t ino) {
>   
>   #ifdef USE_MEMORY_DB
>   
> -static void
> +void
>   pdb_backup() {
>           sqlite3_backup *pBackup;
>           /* no point in doing this if we don't have a database to back up,
> diff --git a/pseudo_db.h b/pseudo_db.h
> index 5a4aa59..9d01232 100644
> --- a/pseudo_db.h
> +++ b/pseudo_db.h
> @@ -26,6 +26,7 @@ typedef struct {
>   	char *program;
>   } log_entry;
>   
> +extern void pdb_backup(void);
>   extern int pdb_maybe_backup(void);
>   extern int pdb_cancel_unlink_file(pseudo_msg_t *msg);
>   extern int pdb_did_unlink_file(char *path, pseudo_msg_t *msg, int deleting);
> diff --git a/pseudo_server.c b/pseudo_server.c
> index 84cef05..815c76b 100644
> --- a/pseudo_server.c
> +++ b/pseudo_server.c
> @@ -568,6 +568,7 @@ serve_client(int i) {
>   				}
>   				in->pathlen = (s - response_path) + 1;
>   				/* exit quickly once clients go away, though */
> +                               pdb_backup();
>   				pseudo_server_timeout = 3;
>   			} else {
>   				in->type = PSEUDO_MSG_ACK;
> 
> 
> 
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