Guess update information based on GitHub Actions environment variables

src/appimagetool.c

@@ -502,6 +502,12 @@ main (int argc, char *argv[])
     char* github_token;
     github_token = getenv("GITHUB_TOKEN");
 
+    /* Parse GitHub CI environment variables.
+     * https://docs.github.com/en/actions/configuring-and-managing-workflows/using-environment-variables#default-environment-variables
+     */
+    char* github_repository = getenv("GITHUB_REPOSITORY");
+    char* github_ref = getenv("GITHUB_REF");
+
     /* Parse GitLab CI environment variables.
      * https://docs.gitlab.com/ee/ci/variables/#predefined-variables-environment-variables
      * echo "${CI_PROJECT_URL}/-/jobs/artifacts/${CI_COMMIT_REF_NAME}/raw/QtQuickApp-x86_64.AppImage?job=${CI_JOB_NAME}"
@@ -869,11 +875,10 @@ main (int argc, char *argv[])
                 printf("%s\n", updateinformation);
             }
         }
-
-        /* If the user has not provided update information but we know this is a Travis CI build,
-         * then fill in update information based on TRAVIS_REPO_SLUG */
         if(guess_update_information){
             if(travis_repo_slug){
+                /* If the user has not provided update information but we know this is a Travis CI build,
+                * then fill in update information based on TRAVIS_REPO_SLUG */
                 if(!github_token) {
                     printf("Will not guess update information since $GITHUB_TOKEN is missing,\n");
                     if(0 != strcmp(travis_pull_request, "false")){
@@ -903,6 +908,33 @@ main (int argc, char *argv[])
                         printf("Will not guess update information since zsyncmake is missing\n");
                     }
                 }
+            } else if (github_repository != NULL && github_ref != NULL) {
+                printf("Running on GitHub Actions\n");
+                gchar *zsyncmake_path = g_find_program_in_path ("zsyncmake");
+                if (zsyncmake_path) {
+                    if (strstr(github_ref, "/pull/")) {
+                        printf("Will not calculate update information for GitHub because this is a pull request\n");
+                    } else {
+                        printf("Guessing update information based on $GITHUB_REPOSITORY=%s and $GITHUB_REF=%s\n", github_repository, github_ref);
+                        char buf[1024];
+                        gchar **parts = g_strsplit (github_repository, "/", 2);
+                        char* channel;
+                        if (github_ref != "" && strstr(github_ref, "/continuous/")) {
+                            channel = "latest";
+                        } else {
+                            channel = "continuous";
+                        }
+                        int is_zsync_write_success = snprintf(buf, 1024, "gh-releases-zsync|%s|%s|%s|%s*-%s.AppImage.zsync", parts[0], parts[1], channel, app_name_for_filename, arch);
+                        if (is_zsync_write_success < 0) {
+                            printf("Writing updateinformation failed. zsync information is too long. (> 1024)\n");
+                            exit(is_zsync_write_success);
+                        }
+                        updateinformation = buf;
+                        printf("%s\n", updateinformation);
+                    }
+                } else {
+                    printf("Will not guess update information since zsyncmake is missing\n");
+                }
             } else if(CI_COMMIT_REF_NAME){
                 // ${CI_PROJECT_URL}/-/jobs/artifacts/${CI_COMMIT_REF_NAME}/raw/QtQuickApp-x86_64.AppImage?job=${CI_JOB_NAME}
                 gchar *zsyncmake_path = g_find_program_in_path ("zsyncmake");