Final (?) version of backend API

12 files changed, 386 insertions, 215 deletions

diff --git a/src/crystfel_gui.c b/src/crystfel_gui.c
index d9b9bec1..48c0777a 100644
--- a/src/crystfel_gui.c
+++ b/src/crystfel_gui.c
@@ -45,13 +45,10 @@
 
 #include "crystfelimageview.h"
 #include "crystfelimageview.h"
-#include "crystfel_gui.h"
 #include "gui_peaksearch.h"
 #include "gui_index.h"
 #include "gui_project.h"
 #include "version.h"
-#include "gui_backend_local.h"
-#include "gui_backend_slurm.h"
 
 
 static void show_help(const char *s)
@@ -804,9 +801,6 @@ static void add_gui_message(enum log_msg_type type, const char *msg,
 }
 
 
-const struct crystfel_backend *backends[16];
-
-
 int main(int argc, char *argv[])
 {
 	int c;
@@ -820,11 +814,6 @@ int main(int argc, char *argv[])
 	GtkWidget *toolbar;
 	GtkWidget *button;
 
-	backends[0] = backend_local;
-	backends[1] = backend_slurm;
-	backends[2] = NULL;
-	/* Max 16 */
-
 	/* Long options */
 	const struct option longopts[] = {
 		{"help",               0, NULL,               'h'},
diff --git a/src/crystfel_gui.h b/src/crystfel_gui.h
deleted file mode 100644
index 4d2dcf06..00000000
--- a/src/crystfel_gui.h
+++ /dev/null
@@ -1,45 +0,0 @@
-/*
- * crystfel_gui.h
- *
- * CrystFEL's main graphical user interface
- *
- * Copyright © 2020 Deutsches Elektronen-Synchrotron DESY,
- *                  a research centre of the Helmholtz Association.
- *
- * Authors:
- *   2020 Thomas White <taw@physics.org>
- *
- * This file is part of CrystFEL.
- *
- * CrystFEL is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * CrystFEL is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with CrystFEL.  If not, see <http://www.gnu.org/licenses/>.
- *
- */
-
-#ifndef CRYSTFEL_GUI_H
-#define CRYSTFEL_GUI_H
-
-#include "gui_project.h"
-
-struct crystfel_backend {
-	const char *name;
-	const char *friendly_name;
-	GtkWidget *(*make_parameters)(void);
-	void *(*run_indexing)(struct crystfelproject *proj,
-	                      const char *algo);
-	void (*cancel)(struct crystfelproject *proj);
-};
-
-extern const struct crystfel_backend *backends[];
-
-#endif
diff --git a/src/gui_backend_local.c b/src/gui_backend_local.c
index 2ddf2488..c82e2f2b 100644
--- a/src/gui_backend_local.c
+++ b/src/gui_backend_local.c
@@ -31,16 +31,24 @@
 #include <sys/wait.h>
 #include <gtk/gtk.h>
 
-#include "crystfel_gui.h"
 #include "gui_project.h"
 
 
-struct local_backend_priv
+struct local_indexing_opts
 {
-	struct crystfelproject *proj;  /* FIXME: Once started, the process should
-	                                * be considered detatched.  Therefore, this
-	                                * shouldn't be stored */
+	int n_processes;
+};
+
+
+struct local_indexing_job
+{
+	double frac_complete;
+	int n_frames;
+
+	/* When both these are true, free the job resources */
 	int indexamajig_running;
+	int cancelled;
+
 	guint indexamajig_watch;
 	GPid indexamajig_pid;
 	guint child_watch_source;
@@ -50,12 +58,10 @@ struct local_backend_priv
 
 static void watch_indexamajig(GPid pid, gint status, gpointer vp)
 {
-	struct local_backend_priv *priv = vp;
-	struct crystfelproject *proj = priv->proj;
+	struct local_indexing_job *job = vp;
 	STATUS("Indexamajig exited with status %i\n", status);
-	priv->indexamajig_running = 0;
-	g_spawn_close_pid(priv->indexamajig_pid);
-	remove_infobar(proj);
+	job->indexamajig_running = 0;
+	g_spawn_close_pid(job->indexamajig_pid);
 }
 
 
@@ -64,8 +70,7 @@ static gboolean index_readable(GIOChannel *source, GIOCondition cond,
 {
 	GIOStatus r;
 	GError *err = NULL;
-	struct local_backend_priv *priv = priv;
-	struct crystfelproject *proj = priv->proj;
+	struct local_indexing_job *job = vp;
 	gchar *line;
 
 	r = g_io_channel_read_line(source, &line, NULL, NULL, &err);
@@ -74,7 +79,7 @@ static gboolean index_readable(GIOChannel *source, GIOCondition cond,
 		return FALSE;
 	}
 	if ( r != G_IO_STATUS_NORMAL ) {
-		if ( priv->indexamajig_pid != 0 ) {
+		if ( job->indexamajig_pid != 0 ) {
 			STATUS("Read error?\n");
 		} else {
 			STATUS("End of output (indexamajig exited)\n");
@@ -84,12 +89,9 @@ static gboolean index_readable(GIOChannel *source, GIOCondition cond,
 	chomp(line);
 
 	if ( strstr(line, " images processed, ") != NULL ) {
-		double frac;
 		int n_proc;
 		sscanf(line, "%i ", &n_proc);
-		frac = (double)n_proc/proj->n_frames;
-		gtk_progress_bar_set_fraction(GTK_PROGRESS_BAR(proj->progressbar),
-		                              frac);
+		job->frac_complete = (double)n_proc/job->n_frames;
 	} else {
 		STATUS("%s\n", line);
 	}
@@ -100,7 +102,9 @@ static gboolean index_readable(GIOChannel *source, GIOCondition cond,
 }
 
 
-static int write_file_list(struct crystfelproject *proj)
+static int write_file_list(char **filenames,
+                           char **events,
+                           int n_frames)
 {
 	FILE *fh;
 	int i;
@@ -108,10 +112,10 @@ static int write_file_list(struct crystfelproject *proj)
 	fh = fopen("files.lst", "w");
 	if ( fh == NULL ) return 1;
 
-	for ( i=0; i<proj->n_frames; i++ ) {
-		fprintf(fh, "%s", proj->filenames[i]);
-		if ( proj->events[i] != NULL ) {
-			fprintf(fh, " %s\n", proj->events[i]);
+	for ( i=0; i<n_frames; i++ ) {
+		fprintf(fh, "%s", filenames[i]);
+		if ( events[i] != NULL ) {
+			fprintf(fh, " %s\n", events[i]);
 		} else {
 			fprintf(fh, "\n");
 		}
@@ -143,78 +147,82 @@ void setup_subprocess(gpointer user_data)
 }
 
 
-static void *run_indexing(struct crystfelproject *proj)
+static void *run_indexing(char **filenames,
+                          char **events,
+                          int n_frames,
+                          char *geom_filename,
+                          struct peak_params *peak_search_params,
+                          struct index_params *indexing_params,
+                          void *opts_priv)
 {
+	struct local_indexing_opts *opts = opts_priv;
 	GIOChannel *ioch;
 	char *args[64];
 	char index_str[64];
 	char peaks_str[64];
+	char n_thread_str[64];
 	int n_args;
 	int i;
 	int r;
 	int ch_stderr;
 	GError *error;
-	struct local_backend_priv *priv;
+	struct local_indexing_job *job;
 
-	if ( priv->indexamajig_running != 0 ) {
-		STATUS("Indexamajig already running.\n");
-		return NULL;
-	}
-
-	priv = malloc(sizeof(struct local_backend_priv));
-	if ( priv == NULL ) return NULL;
+	job = malloc(sizeof(struct local_indexing_job));
+	if ( job == NULL ) return NULL;
 
-	priv->proj = proj;
-
-	if ( write_file_list(proj) ) {
+	if ( write_file_list(filenames, events, n_frames) ) {
 		STATUS("Failed to write list\n");
-		free(priv);
+		free(job);
 		return NULL;
 	}
+	job->n_frames = job->n_frames;
 
 	strcpy(index_str, "--indexing=dirax"); /* FIXME */
 
 	strcpy(peaks_str, "--peaks=");
 	strncat(peaks_str,
-	        str_peaksearch(proj->peak_search_params.method), 50);
+	        str_peaksearch(peak_search_params->method), 50);
+
+	snprintf(n_thread_str, 63, "%i", opts->n_processes);
 
 	args[0] = "indexamajig";
 	args[1] = "-i";
 	args[2] = "files.lst";
 	args[3] = "-g";
-	args[4] = proj->geom_filename;
+	args[4] = geom_filename;
 	args[5] = "-o";
 	args[6] = "test.stream";
 	args[7] = index_str;
 	args[8] = "--no-check-cell";
 	args[9] = "-j";
-	args[10] = "1";
+	args[10] = n_thread_str;
 	args[11] = "--integration=none";
 	args[12] = peaks_str;
 	n_args = 13;
 
-	if ( proj->peak_search_params.method == PEAK_ZAEF ) {
+	if ( peak_search_params->method == PEAK_ZAEF ) {
 		add_arg(args, n_args++, "threshold",
-		        proj->peak_search_params.threshold);
+		        peak_search_params->threshold);
 		add_arg(args, n_args++, "min-squared-gradient",
-		        proj->peak_search_params.min_sq_gradient);
+		        peak_search_params->min_sq_gradient);
 		add_arg(args, n_args++, "min-snr",
-		        proj->peak_search_params.min_snr);
-	} else if ( proj->peak_search_params.method == PEAK_PEAKFINDER8 ) {
+		        peak_search_params->min_snr);
+	} else if ( peak_search_params->method == PEAK_PEAKFINDER8 ) {
 		add_arg(args, n_args++, "threshold",
-		        proj->peak_search_params.threshold);
+		        peak_search_params->threshold);
 		add_arg(args, n_args++, "min-snr",
-		        proj->peak_search_params.min_snr);
+		        peak_search_params->min_snr);
 		add_arg(args, n_args++, "min-pix-count",
-		        proj->peak_search_params.min_pix_count);
+		        peak_search_params->min_pix_count);
 		add_arg(args, n_args++, "max-pix-count",
-		        proj->peak_search_params.max_pix_count);
+		        peak_search_params->max_pix_count);
 		add_arg(args, n_args++, "local-bg-radius",
-		        proj->peak_search_params.local_bg_radius);
+		        peak_search_params->local_bg_radius);
 		add_arg(args, n_args++, "min-res",
-		        proj->peak_search_params.min_res);
+		        peak_search_params->min_res);
 		add_arg(args, n_args++, "max-res",
-		        proj->peak_search_params.max_res);
+		        peak_search_params->max_res);
 	}
 
 	args[n_args] = NULL;
@@ -228,55 +236,137 @@ static void *run_indexing(struct crystfelproject *proj)
 	                             G_SPAWN_SEARCH_PATH
 	                           | G_SPAWN_DO_NOT_REAP_CHILD,
 	                             setup_subprocess, NULL,
-	                             &priv->indexamajig_pid,
+	                             &job->indexamajig_pid,
 	                             NULL, NULL, &ch_stderr,
 	                             &error);
 	if ( r == FALSE ) {
 		ERROR("Failed to run indexamajig: %s\n",
 		      error->message);
-		free(priv);
+		free(job);
 		return NULL;
 	}
-	priv->indexamajig_running = 1;
+	job->indexamajig_running = 1;
 
-	priv->child_watch_source = g_child_watch_add(priv->indexamajig_pid,
-	                                             watch_indexamajig,
-	                                             priv);
+	job->child_watch_source = g_child_watch_add(job->indexamajig_pid,
+	                                            watch_indexamajig,
+	                                            job);
 
 	ioch = g_io_channel_unix_new(ch_stderr);
-	priv->index_readable_source = g_io_add_watch(ioch,
-	                                             G_IO_IN | G_IO_ERR | G_IO_HUP,
-	                                             index_readable,
-	                                             priv);
+	job->index_readable_source = g_io_add_watch(ioch,
+	                                            G_IO_IN | G_IO_ERR | G_IO_HUP,
+	                                            index_readable,
+	                                            job);
+
+	return job;
+}
+
+
+static void cancel_indexing(void *job_priv)
+{
+	struct local_indexing_job *job = job_priv;
+
+	if ( !job->indexamajig_running ) return;
+
+	ERROR("Stopping indexamajig (pid %i).\n", job->indexamajig_pid);
+	kill(-job->indexamajig_pid, SIGINT);
+}
+
+
+static int convert_int(const char *str, int *pval)
+{
+	int val;
+	char *rval;
 
-	return priv;
+	val = strtod(str, &rval);
+	if ( *rval != '\0' ) {
+		return 1;
+	} else {
+		*pval = val;
+		return 0;
+	}
 }
 
 
-static void cancel(void *vp)
+static void n_processes_activate_sig(GtkEntry *entry, gpointer data)
 {
-	struct local_backend_priv *priv = vp;
+	struct local_indexing_opts *opts = data;
+	convert_int(gtk_entry_get_text(entry), &opts->n_processes);
+}
 
-	if ( !priv->indexamajig_running ) return;
 
-	ERROR("Stopping indexamajig (pid %i).\n", priv->indexamajig_pid);
-	kill(-priv->indexamajig_pid, SIGINT);
+static GtkWidget *make_indexing_parameters_widget(void *opts_priv)
+{
+	struct local_indexing_opts *opts = opts_priv;
+	GtkWidget *vbox;
+	GtkWidget *hbox;
+	GtkWidget *entry;
+	GtkWidget *label;
+	char tmp[64];
+
+	vbox = gtk_box_new(GTK_ORIENTATION_VERTICAL, 0);
+
+	hbox = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 8);
+	gtk_box_pack_start(GTK_BOX(vbox), GTK_WIDGET(hbox),
+	                   FALSE, FALSE, 0);
+	label = gtk_label_new("Number of threads:");
+	gtk_box_pack_start(GTK_BOX(hbox), GTK_WIDGET(label),
+	                   FALSE, FALSE, 0);
+	entry = gtk_entry_new();
+	snprintf(tmp, 63, "%i", opts->n_processes);
+	gtk_entry_set_width_chars(GTK_ENTRY(entry), 5);
+	gtk_box_pack_start(GTK_BOX(hbox), GTK_WIDGET(entry),
+	                   FALSE, FALSE, 0);
+
+	g_signal_connect(G_OBJECT(entry), "activate",
+	                 G_CALLBACK(n_processes_activate_sig),
+	                 opts);
+	return vbox;
 }
 
 
-static GtkWidget *make_parameters(void)
+static struct local_indexing_opts *make_default_local_opts()
 {
-	return gtk_label_new("Local params");
+	struct local_indexing_opts *opts = malloc(sizeof(struct local_indexing_opts));
+	if ( opts == NULL ) return NULL;
+
+	opts->n_processes = 4;
+
+	return opts;
 }
 
 
-struct crystfel_backend _backend_local =
-	{
-	 .name = "local",
-	 .friendly_name = "Local (run on this computer)",
-	 .make_parameters = make_parameters,
-	 .run_indexing = run_indexing,
-	 .cancel = cancel,
-	};
+static void write_indexing_opts(void *opts_priv, FILE *fh)
+{
+	struct local_indexing_opts *opts = opts_priv;
+
+	fprintf(fh, "indexing.local.n_processes %i\n",
+	        opts->n_processes);
+}
+
 
-const struct crystfel_backend *backend_local = &_backend_local;
+static void read_indexing_opt(void *opts_priv,
+                              const char *key,
+                              const char *val)
+{
+	//struct local_indexing_opts *opts = opts_priv;
+
+	STATUS("Local got %s = '%s'\n", key, val);
+	/* FIXME: Parse and set */
+}
+
+
+int make_local_backend(struct crystfel_backend *be)
+{
+	be->name = "local";
+	be->friendly_name = "Local (run on this computer)";
+
+	be->make_indexing_parameters_widget = make_indexing_parameters_widget;
+	be->run_indexing = run_indexing;
+	be->cancel_indexing = cancel_indexing;
+	be->indexing_opts_priv = make_default_local_opts();
+	if ( be->indexing_opts_priv == NULL ) return 1;
+	be->write_indexing_opts = write_indexing_opts;
+	be->read_indexing_opt = read_indexing_opt;
+
+	return 0;
+};
diff --git a/src/gui_backend_local.h b/src/gui_backend_local.h
index 94724e98..5b3fd7d4 100644
--- a/src/gui_backend_local.h
+++ b/src/gui_backend_local.h
@@ -29,8 +29,8 @@
 #ifndef GUI_BACKEND_LOCAL_H
 #define GUI_BACKEND_LOCAL_H
 
-#include "crystfel_gui.h"
+#include "gui_project.h"
 
-extern const struct crystfel_backend *backend_local;
+extern int make_local_backend(struct crystfel_backend *be);
 
 #endif
diff --git a/src/gui_backend_slurm.c b/src/gui_backend_slurm.c
index b5c75bb5..cb0cee59 100644
--- a/src/gui_backend_slurm.c
+++ b/src/gui_backend_slurm.c
@@ -31,39 +31,101 @@
 #include <sys/wait.h>
 #include <gtk/gtk.h>
 
-#include "crystfel_gui.h"
+#include "gui_project.h"
 
 
-struct slurm_backend_priv
+struct slurm_indexing_opts
 {
-	int dummy;
+	char *partition;
+	int block_size;
+	char *email_address;
 };
 
 
-static void cancel(void *vp)
+struct slurm_indexing_job
 {
+	double frac_complete;
+	/* FIXME: List of SLURM job numbers to track */
+};
+
+
+static void cancel_indexing(void *job_priv)
+{
+	//struct slurm_indexing_job *job = job_priv;
 }
 
 
-static void *run_indexing(struct crystfelproject *proj)
+static void *run_indexing(char **filenames,
+                          char **events,
+                          int n_frames,
+                          char *geom_filename,
+                          struct peak_params *peak_search_params,
+                          struct index_params *indexing_params,
+                          void *opts_priv)
 {
+	//struct slurm_indexing_opts *opts = opts_priv;
 	return NULL;
 }
 
 
-static GtkWidget *make_parameters(void)
+static GtkWidget *make_indexing_parameters_widget(void *opts_priv)
 {
+	//struct slurm_indexing_opts *opts = opts_priv;
+
 	return gtk_label_new("SLURM params");
 }
 
 
-const struct crystfel_backend _backend_slurm =
-	{
-	 .name = "slurm",
-	 .friendly_name = "SLURM",
-	 .make_parameters = make_parameters,
-	 .run_indexing = run_indexing,
-	 .cancel = cancel,
-	};
+static struct slurm_indexing_opts *make_default_slurm_opts()
+{
+	struct slurm_indexing_opts *opts = malloc(sizeof(struct slurm_indexing_opts));
+	if ( opts == NULL ) return NULL;
+
+	opts->partition = NULL;
+	opts->block_size = 1000;
+	opts->email_address = NULL;
 
-const struct crystfel_backend *backend_slurm = &_backend_slurm;
+	return opts;
+}
+
+
+static void write_indexing_opts(void *opts_priv, FILE *fh)
+{
+	struct slurm_indexing_opts *opts = opts_priv;
+
+	fprintf(fh, "indexing.slurm.block_size %i\n",
+	        opts->block_size);
+	fprintf(fh, "indexing.slurm.partition %s\n",
+	        opts->partition);
+	fprintf(fh, "indexing.slurm.email_address %s\n",
+	        opts->email_address);
+}
+
+
+static void read_indexing_opt(void *opts_priv,
+                              const char *key,
+                              const char *val)
+{
+	//struct slurm_indexing_opts *opts = opts_priv;
+
+	STATUS("SLURM got %s = '%s'\n", key, val);
+	/* FIXME: Parse and set */
+}
+
+
+int make_slurm_backend(struct crystfel_backend *be)
+{
+	be->name = "slurm";
+	be->friendly_name = "SLURM";
+
+	be->make_indexing_parameters_widget = make_indexing_parameters_widget;
+	be->run_indexing = run_indexing;
+	be->cancel_indexing = cancel_indexing;
+	be->write_indexing_opts = write_indexing_opts;
+	be->read_indexing_opt = read_indexing_opt;
+
+	be->indexing_opts_priv = make_default_slurm_opts();
+	if ( be->indexing_opts_priv == NULL ) return 1;
+
+	return 0;
+};
diff --git a/src/gui_backend_slurm.h b/src/gui_backend_slurm.h
index 9865aa2a..28eec2e3 100644
--- a/src/gui_backend_slurm.h
+++ b/src/gui_backend_slurm.h
@@ -29,8 +29,8 @@
 #ifndef GUI_BACKEND_SLURM_H
 #define GUI_BACKEND_SLURM_H
 
-#include "crystfel_gui.h"
+#include "gui_project.h"
 
-extern const struct crystfel_backend *backend_slurm;
+extern int make_slurm_backend(struct crystfel_backend *be);
 
 #endif
diff --git a/src/gui_index.c b/src/gui_index.c
index 9fdc0c4e..45ae943b 100644
--- a/src/gui_index.c
+++ b/src/gui_index.c
@@ -46,9 +46,9 @@
 #include <integration.h>
 #include <predict-refine.h>
 
-#include "crystfel_gui.h"
 #include "crystfelimageview.h"
 #include "crystfelindexingopts.h"
+#include "gui_project.h"
 
 void cell_explorer_sig(struct crystfelproject *proj)
 {
@@ -68,11 +68,57 @@ void cell_explorer_sig(struct crystfelproject *proj)
 }
 
 
+static void get_indexing_opts(struct crystfelproject *proj,
+                              CrystFELIndexingOpts *opts)
+{
+	/* Indexing */
+	proj->indexing_params.cell_file = crystfel_indexing_opts_get_cell_file(opts);
+	proj->indexing_params.indexing_methods = crystfel_indexing_opts_get_indexing_method_string(opts);
+	proj->indexing_params.multi = crystfel_indexing_opts_get_multi_lattice(opts);
+	proj->indexing_params.no_refine = !crystfel_indexing_opts_get_refine(opts);
+	proj->indexing_params.no_retry = !crystfel_indexing_opts_get_retry(opts);
+	proj->indexing_params.no_peak_check = !crystfel_indexing_opts_get_peak_check(opts);
+	proj->indexing_params.no_cell_check = !crystfel_indexing_opts_get_cell_check(opts);
+	proj->indexing_params.min_peaks = crystfel_indexing_opts_get_min_peaks(opts);
+
+	/* Integration */
+	proj->indexing_params.integration_method = crystfel_indexing_opts_get_integration_method_string(opts);
+	proj->indexing_params.overpredict = crystfel_indexing_opts_get_overpredict(opts);
+	proj->indexing_params.push_res = crystfel_indexing_opts_get_push_res(opts);
+}
+
+
+static void run_indexing_all(struct crystfelproject *proj)
+{
+	int backend_idx;
+	struct crystfel_backend *be;
+	void *job_priv;
+
+	get_indexing_opts(proj,
+	                  CRYSTFEL_INDEXING_OPTS(proj->indexing_opts));
+
+
+	backend_idx = gtk_combo_box_get_active(GTK_COMBO_BOX(proj->indexing_backend_combo));
+	if ( backend_idx < 0 ) return;
+
+	be = &proj->backends[backend_idx];
+	job_priv = be->run_indexing(proj->filenames,
+	                            proj->events,
+	                            proj->n_frames,
+	                            proj->geom_filename,
+	                            &proj->peak_search_params,
+	                            &proj->indexing_params,
+	                            be->indexing_opts_priv);
+
+	STATUS("Started job %p\n", job_priv);
+}
+
+
 static void index_all_response_sig(GtkWidget *dialog, gint resp,
                                    struct crystfelproject *proj)
 {
 	if ( resp == GTK_RESPONSE_OK ) {
-		STATUS("OK!\n");
+		run_indexing_all(proj);
 	}
 
 	gtk_widget_destroy(dialog);
@@ -80,23 +126,27 @@ static void index_all_response_sig(GtkWidget *dialog, gint resp,
 }
 
 
-static void backend_changed_sig(GtkWidget *combo,
-                                struct crystfelproject *proj)
+static void indexing_backend_changed_sig(GtkWidget *combo,
+                                         struct crystfelproject *proj)
 {
 	int backend_idx;
+	struct crystfel_backend *be;
 
 	backend_idx = gtk_combo_box_get_active(GTK_COMBO_BOX(combo));
 	if ( backend_idx < 0 ) return;
 
-	if ( proj->backend_opts != NULL ) {
-		gtk_widget_destroy(proj->backend_opts);
+	be = &proj->backends[backend_idx];
+
+	if ( proj->indexing_backend_opts_widget != NULL ) {
+		gtk_widget_destroy(proj->indexing_backend_opts_widget);
 	}
-	proj->backend_opts = backends[backend_idx]->make_parameters();
 
-	gtk_box_pack_start(GTK_BOX(proj->backend_opts_box),
-	                   GTK_WIDGET(proj->backend_opts),
+	proj->indexing_backend_opts_widget = be->make_indexing_parameters_widget(be->indexing_opts_priv);
+
+	gtk_box_pack_start(GTK_BOX(proj->indexing_backend_opts_box),
+	                   GTK_WIDGET(proj->indexing_backend_opts_widget),
 	                   FALSE, FALSE, 0);
-	gtk_widget_show_all(proj->backend_opts);
+	gtk_widget_show_all(proj->indexing_backend_opts_widget);
 }
 
 
@@ -105,7 +155,6 @@ static GtkWidget *make_backend_opts(struct crystfelproject *proj)
 	GtkWidget *box;
 	GtkWidget *hbox;
 	GtkWidget *label;
-	GtkWidget *combo;
 	int i;
 
 	box = gtk_box_new(GTK_ORIENTATION_VERTICAL, 8);
@@ -118,28 +167,27 @@ static GtkWidget *make_backend_opts(struct crystfelproject *proj)
 	gtk_box_pack_start(GTK_BOX(hbox), GTK_WIDGET(label),
 	                   FALSE, FALSE, 0);
 
-	combo = gtk_combo_box_text_new();
-	gtk_box_pack_start(GTK_BOX(hbox), GTK_WIDGET(combo),
+	proj->indexing_backend_combo = gtk_combo_box_text_new();
+	gtk_box_pack_start(GTK_BOX(hbox), GTK_WIDGET(proj->indexing_backend_combo),
 	                   FALSE, FALSE, 0);
 
-	i = 0;
-	do {
-		gtk_combo_box_text_append(GTK_COMBO_BOX_TEXT(combo),
-		                          backends[i]->name,
-		                          backends[i]->friendly_name);
-	} while ( backends[++i] != NULL );
+	for ( i=0; i<proj->n_backends; i++ ) {
+		gtk_combo_box_text_append(GTK_COMBO_BOX_TEXT(proj->indexing_backend_combo),
+		                          proj->backends[i].name,
+		                          proj->backends[i].friendly_name);
+	}
 
-	proj->backend_opts_box = gtk_box_new(GTK_ORIENTATION_VERTICAL,
-	                                     0);
+	proj->indexing_backend_opts_box = gtk_box_new(GTK_ORIENTATION_VERTICAL,
+	                                              0);
 	gtk_box_pack_start(GTK_BOX(box),
-	                   GTK_WIDGET(proj->backend_opts_box),
+	                   GTK_WIDGET(proj->indexing_backend_opts_box),
 	                   FALSE, FALSE, 0);
-	proj->backend_opts = NULL;
+	proj->indexing_backend_opts_widget = NULL;
 
-	/* proj->backend_opts{_box} must exist before the following */
-	g_signal_connect(G_OBJECT(combo), "changed",
-	                 G_CALLBACK(backend_changed_sig), proj);
-	gtk_combo_box_set_active(GTK_COMBO_BOX(combo), 0);
+	/* proj->indexing_backend_opts{_box} must exist before the following */
+	g_signal_connect(G_OBJECT(proj->indexing_backend_combo), "changed",
+	                 G_CALLBACK(indexing_backend_changed_sig), proj);
+	gtk_combo_box_set_active(GTK_COMBO_BOX(proj->indexing_backend_combo), 0);
 
 	return box;
 }
@@ -166,26 +214,6 @@ static void set_indexing_opts(struct crystfelproject *proj,
 }
 
 
-static void get_indexing_opts(struct crystfelproject *proj,
-                              CrystFELIndexingOpts *opts)
-{
-	/* Indexing */
-	proj->indexing_params.cell_file = crystfel_indexing_opts_get_cell_file(opts);
-	proj->indexing_params.indexing_methods = crystfel_indexing_opts_get_indexing_method_string(opts);
-	proj->indexing_params.multi = crystfel_indexing_opts_get_multi_lattice(opts);
-	proj->indexing_params.no_refine = !crystfel_indexing_opts_get_refine(opts);
-	proj->indexing_params.no_retry = !crystfel_indexing_opts_get_retry(opts);
-	proj->indexing_params.no_peak_check = !crystfel_indexing_opts_get_peak_check(opts);
-	proj->indexing_params.no_cell_check = !crystfel_indexing_opts_get_cell_check(opts);
-	proj->indexing_params.min_peaks = crystfel_indexing_opts_get_min_peaks(opts);
-
-	/* Integration */
-	proj->indexing_params.integration_method = crystfel_indexing_opts_get_integration_method_string(opts);
-	proj->indexing_params.overpredict = crystfel_indexing_opts_get_overpredict(opts);
-	proj->indexing_params.push_res = crystfel_indexing_opts_get_push_res(opts);
-}
-
-
 gint index_all_sig(GtkWidget *widget, struct crystfelproject *proj)
 {
 	GtkWidget *dialog;
@@ -220,9 +248,9 @@ gint index_all_sig(GtkWidget *widget, struct crystfelproject *proj)
 	gtk_notebook_append_page(GTK_NOTEBOOK(proj->indexing_opts),
 	                         backend_page,
 	                         gtk_label_new("Cluster/batch system"));
-	proj->backend_opts_box = gtk_vbox_new(FALSE, 0.0);
+	proj->indexing_backend_opts_box = gtk_vbox_new(FALSE, 0.0);
 	gtk_box_pack_start(GTK_BOX(backend_page),
-	                   proj->backend_opts_box,
+	                   proj->indexing_backend_opts_box,
 	                   FALSE, FALSE, 8.0);
 
 	gtk_dialog_set_default_response(GTK_DIALOG(dialog),
diff --git a/src/gui_index.h b/src/gui_index.h
index 474e7c0b..991151ef 100644
--- a/src/gui_index.h
+++ b/src/gui_index.h
@@ -31,7 +31,7 @@
 
 #include <gtk/gtk.h>
 
-#include "crystfel_gui.h"
+#include "gui_project.h"
 
 extern gint index_one_sig(GtkWidget *widget,
                           struct crystfelproject *proj);
diff --git a/src/gui_peaksearch.c b/src/gui_peaksearch.c
index fc82ed80..c3444fe4 100644
--- a/src/gui_peaksearch.c
+++ b/src/gui_peaksearch.c
@@ -42,8 +42,8 @@
 #include <datatemplate.h>
 #include <peaks.h>
 
-#include "crystfel_gui.h"
 #include "crystfelimageview.h"
+#include "gui_project.h"
 
 
 void update_peaks(struct crystfelproject *proj)
diff --git a/src/gui_peaksearch.h b/src/gui_peaksearch.h
index 5124acdb..68443d5e 100644
--- a/src/gui_peaksearch.h
+++ b/src/gui_peaksearch.h
@@ -31,7 +31,7 @@
 
 #include <gtk/gtk.h>
 
-#include "crystfel_gui.h"
+#include "gui_project.h"
 
 extern gint peaksearch_sig(GtkWidget *widget,
                            struct crystfelproject *proj);
diff --git a/src/gui_project.c b/src/gui_project.c
index f383f77b..a38cc305 100644
--- a/src/gui_project.c
+++ b/src/gui_project.c
@@ -36,9 +36,9 @@
 #include <string.h>
 #include <assert.h>
 
-#include "crystfel_gui.h"
-#include "gui_backend_local.h"
 #include "gui_project.h"
+#include "gui_backend_local.h"
+#include "gui_backend_slurm.h"
 
 static double parse_float(const char *val)
 {
@@ -262,10 +262,6 @@ static void handle_var(const char *key, const char *val,
 		proj->show_refls = parse_int(val);
 	}
 
-	if ( strcmp(key, "backend") == 0 ) {
-		proj->backend_name = strdup(val);
-	}
-
 	if ( strcmp(key, "geom") == 0 ) {
 		proj->geom_filename = strdup(val);
 	}
@@ -340,6 +336,8 @@ int load_project(struct crystfelproject *proj)
 	fh = fopen("crystfel.project", "r");
 	if ( fh == NULL ) return 1;
 
+	default_project(proj);
+
 	do {
 
 		char *sp;
@@ -474,7 +472,6 @@ int save_project(struct crystfelproject *proj)
 
 	fprintf(fh, "show_peaks %i\n", proj->show_peaks);
 	fprintf(fh, "show_refls %i\n", proj->show_refls);
-	fprintf(fh, "backend %s\n", proj->backend_name);
 
 	fprintf(fh, "-----\n");
 	if ( proj->stream == NULL ) {
@@ -503,7 +500,6 @@ void default_project(struct crystfelproject *proj)
 	proj->events = NULL;
 	proj->peak_params = NULL;
 	proj->info_bar = NULL;
-	proj->backend_name = strdup("local");
 	proj->data_top_folder = NULL;
 	proj->data_search_pattern = 0;
 	proj->stream_filename = NULL;
@@ -512,6 +508,19 @@ void default_project(struct crystfelproject *proj)
 	proj->cur_image = NULL;
 	proj->indexing_opts = NULL;
 
+	/* FIXME: Crappy error handling */
+	proj->n_backends = 2;
+	proj->backends = malloc(proj->n_backends*sizeof(struct crystfel_backend));
+	if ( proj->backends == NULL ) {
+		ERROR("Couldn't allocate space for backends\n");
+	}
+	if ( make_local_backend(&proj->backends[0]) ) {
+		ERROR("Local backend setup failed\n");
+	}
+	if ( make_slurm_backend(&proj->backends[1]) ) {
+		ERROR("SLURM backend setup failed\n");
+	}
+
 	/* Default parameter values */
 	proj->show_peaks = 0;
 	proj->show_refls = 0;
diff --git a/src/gui_project.h b/src/gui_project.h
index 0c7e9616..42ab43f1 100644
--- a/src/gui_project.h
+++ b/src/gui_project.h
@@ -34,6 +34,7 @@
 #include <peaks.h>
 #include <stream.h>
 
+
 enum match_type_id
 {
 	 MATCH_EVERYTHING,
@@ -83,6 +84,40 @@ struct index_params {
 	float push_res;
 };
 
+struct crystfel_backend {
+
+	const char *name;
+	const char *friendly_name;
+
+	/* Backend should provide a GTK widget to set options */
+	GtkWidget *(*make_indexing_parameters_widget)(void *opts_priv);
+
+	/* Called to ask the backend to start indexing frames.
+	 * It should return a void pointer representing this job */
+	void *(*run_indexing)(char **filenames,
+	                      char **events,
+	                      int n_frames,
+	                      char *geom_filename,
+	                      struct peak_params *peak_search_params,
+	                      struct index_params *indexing_params,
+	                      void *opts_priv);
+
+	/* Called to ask the backend to cancel the job */
+	void (*cancel_indexing)(void *job_priv);
+
+	/* Called to ask the backend to write its indexing options */
+	void (*write_indexing_opts)(void *opts_priv, FILE *fh);
+
+	/* Called when reading a project from file */
+	void (*read_indexing_opt)(void *opts_priv,
+	                          const char *key,
+	                          const char *val);
+
+	/* Backend should store options for indexing here */
+	void *indexing_opts_priv;
+
+};
+
 struct crystfelproject {
 
 	GtkWidget *window;
@@ -119,15 +154,18 @@ struct crystfelproject {
 	int show_refls;
 	struct index_params indexing_params;
 	GtkWidget *indexing_opts;
+	GtkWidget *indexing_backend_combo;
+	GtkWidget *indexing_backend_opts_widget;
+	GtkWidget *indexing_backend_opts_box;
 
 	GtkWidget *type_combo;
 	GtkWidget *peak_vbox;     /* Box for peak search parameter widgets */
 	GtkWidget *peak_params;   /* Peak search parameter widgets */
 	struct peak_params original_params;
 
-	char *backend_name;
-	GtkWidget *backend_opts;
-	GtkWidget *backend_opts_box;
+	/* All the backends available in this project */
+	struct crystfel_backend *backends;
+	int n_backends;
 
 	GtkWidget *info_bar;
 	GtkWidget *progressbar;